CA1117588A - Prime mover, method of operating such and circuit - Google Patents
Prime mover, method of operating such and circuitInfo
- Publication number
- CA1117588A CA1117588A CA000312801A CA312801A CA1117588A CA 1117588 A CA1117588 A CA 1117588A CA 000312801 A CA000312801 A CA 000312801A CA 312801 A CA312801 A CA 312801A CA 1117588 A CA1117588 A CA 1117588A
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- Prior art keywords
- prime mover
- ptcr
- generally
- circuit
- winding means
- Prior art date
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Abstract
Abstract of the Disclosure A prime move adapted for energization to a preselected speed therefor across a power source. The prime mover has a pair of winding means for excitation so as to effect the energization of the prime mover generally to the preselected speed when it is energized across the power source. Means is provided in circuit relation with one of the winding means and the power source for inhibiting the excitation of the one winding means generally as the prime mover attains its preselected speed, and means is operable generally in response to the occurrence of a preselected condition with respect to the excitation of the other of the winding means for placing the inhibiting means in open circuit relation with the power source generally as the prime mover attains preselected speed.
A method of operating a prime mover, a method of interrupting the operation of means for inhibiting current flow therethrough, and a circuit are also disclosed.
A method of operating a prime mover, a method of interrupting the operation of means for inhibiting current flow therethrough, and a circuit are also disclosed.
Description
~7~ 3D-AC-5010 This invention relates yenerally to prime movers and in particular to such prime movers having auxiliary skarting devices, a method of operating a prime mover, and a circuit.
In the past, various types of prime movers, such as dynamoelectric machines or electric motors for instance, were provided with a winding circuit in a stationary assembly, such as a stator or the like, having parallel connected main or run winding means and an auxiliary or start winding means. During a starting mode of these past types of prime movers, the winding circuit thereof was initially connected across a power source or line by suitable operator operated switching means to effect the generally conjoint excitation of the main winding means and the start winding means at least until a rotatable assembly magnetically associated with the main winding means and the auxiliary winding means of the stationary assembly was energized generally to a preselected speed.
Of course, various prior art mechanisms or devices were utilized to render the auxiliary winding means ineffective in the winding circuit generally when the preselected speed of the prime mover, i.e~, the rotatable assembly thereof, was attained.
Some of these prior art devices for controlling the excitation of the auxiliary winding means were mechanical speed responsive devices. For instance, when the rotatable assembly attained the preselected speed, a centrifugal mechanism carried on the rotatable assembly was actuated to move an associated collar generally axially on the rotatable assembly ~ 03-AC-5010 ~;
.. , ~
from an at-re3t po3ition ~oward another position, and upon such axial movement to itg another position, the aollar drove linkage means for operating a switch which efected the de- ~, excitation of the auxiliAry winding means by disconnecting it from the power source. Thug~ with the auxiliary winding means rendered ineffective in the winding circuit, the prime mover then was energized generally at the preselected speed thereof in response to the continued excita~i~n of the main winding means.
Of course, at least one of the disadvantageous or undesirable ' features of the aforementioned centrifugal mechanism and associated linkage means is believed to be those well-known limitations attributable to most all mechanical devices, such as tolerance problems, wear problems, noise problems and, in sQme instances reliability problems.
In other types of these prior art prime movers, a current relay was employed for controlling the excitation of the auxiliary winding means. For instance, a coil of the current relay was serially connected in the winding circuit with the main winding means thereof, and contact means of the current relay was serially ~onnected in the winding circuit with the auxiliary winding means thereof. When the prime mover was energized across the line, as previously mentioned, the coil of the current relay and the main winding means were excited, and the excitation of the relay coil effected the ~ 25 magnetlc closure of the contact means of the relay so as to ; effect the excitation of the auxiliary winding means; therefore, in this manner, the main winding means and the auxiliary winding means were conjointly excited to energize the prime mover to generally its preselected speed during a starting mode thereof.
- 30 Of course, when the prime mover was so energized generally '
In the past, various types of prime movers, such as dynamoelectric machines or electric motors for instance, were provided with a winding circuit in a stationary assembly, such as a stator or the like, having parallel connected main or run winding means and an auxiliary or start winding means. During a starting mode of these past types of prime movers, the winding circuit thereof was initially connected across a power source or line by suitable operator operated switching means to effect the generally conjoint excitation of the main winding means and the start winding means at least until a rotatable assembly magnetically associated with the main winding means and the auxiliary winding means of the stationary assembly was energized generally to a preselected speed.
Of course, various prior art mechanisms or devices were utilized to render the auxiliary winding means ineffective in the winding circuit generally when the preselected speed of the prime mover, i.e~, the rotatable assembly thereof, was attained.
Some of these prior art devices for controlling the excitation of the auxiliary winding means were mechanical speed responsive devices. For instance, when the rotatable assembly attained the preselected speed, a centrifugal mechanism carried on the rotatable assembly was actuated to move an associated collar generally axially on the rotatable assembly ~ 03-AC-5010 ~;
.. , ~
from an at-re3t po3ition ~oward another position, and upon such axial movement to itg another position, the aollar drove linkage means for operating a switch which efected the de- ~, excitation of the auxiliAry winding means by disconnecting it from the power source. Thug~ with the auxiliary winding means rendered ineffective in the winding circuit, the prime mover then was energized generally at the preselected speed thereof in response to the continued excita~i~n of the main winding means.
Of course, at least one of the disadvantageous or undesirable ' features of the aforementioned centrifugal mechanism and associated linkage means is believed to be those well-known limitations attributable to most all mechanical devices, such as tolerance problems, wear problems, noise problems and, in sQme instances reliability problems.
In other types of these prior art prime movers, a current relay was employed for controlling the excitation of the auxiliary winding means. For instance, a coil of the current relay was serially connected in the winding circuit with the main winding means thereof, and contact means of the current relay was serially ~onnected in the winding circuit with the auxiliary winding means thereof. When the prime mover was energized across the line, as previously mentioned, the coil of the current relay and the main winding means were excited, and the excitation of the relay coil effected the ~ 25 magnetlc closure of the contact means of the relay so as to ; effect the excitation of the auxiliary winding means; therefore, in this manner, the main winding means and the auxiliary winding means were conjointly excited to energize the prime mover to generally its preselected speed during a starting mode thereof.
- 30 Of course, when the prime mover was so energized generally '
2--0~-~C-501~
to its preselected speed, ~he current d~aw of the main winding means was appreciably reduc~d, an~ such reduction of current caused the relay coil to weaken its magnetic affect thereby to permit the contact means of the current relay to return to their at-rest or open position. Thus, with the relay contacts so opened to interrupt current flow to the auxiliary winding means, the auxiliary winding means were rendered ineffective generally at the time the prime mover attains its preselected speed, and the prime mover - lO remained energized generally at the preselected speed thereof during its~running mode in response to the continued excitation of the main winding means. At least one of the disadvantageous or undesirabIe features of such past prime movers utilizing a current relay for controlling excitation of the auxiliary winding means is believed to be that the contact means of the current relay had a tendency to weld in response to the'generally large current draw by the auxiliary windings during the starting operation of the prime mover.
Another disadvantageous or undesirable feature is believed to be'that the'current reIay generated radio and television interference at the instant of make and break due to arcing of the contact means.
In the event a capacitor was utilizecl in series circuit relation with'the''auxiliary winding of the aforementioned prime mover utilizing the current relay, the starting torque of the such'prime mover may be'increased wherein the capacitor may limit the'amount of current in the auxiliary winding ~ 03-AC-5010 ,' ,,.
to a safe value while electr1cally shiting its phase, l;
Again, however, the aforementloned disadvantage or undesirable feature is bel,ieved to be that the allowable magnitude of the "
current drawn by the auxiliary winding ls limited by the relay contact means to resist welding which may occur when the ~' capacitor is discharged directly through the relay contact ,, means during the starting operation of the prime mover. For instance, if the relay contact means make, break and remake '' during the starting operation of the prime mover, the capacitor may be charged to a peak voltage value, disconnected, and then ' reconnected one hun~red eighty electrical degrees (180) later to a peak opposite polarity line. Thus, the resultant discharge is at double peak value. It is also believed that the use of ' a relatively large capacitor, for maximum starting torque of the aforementioned prime mover utilizing a current relay, may also be impracticable generally for the same reasons as discussed above.
Another one of the prior art devices for controlling the excitation of the auxiliary winding means was a positive temperature coeff.icient resistor (PTCR) which was connected in series with the auxiliary winding of the prime mover. When the prime mover was energized across the line, the main winding means and auxiliary winding means were initially conjointly excited since the PTCR exhibited little initial resistance to ~~ 25 current flow to the auxiliary winding means. The PTCR acts generally as a low value resistor until its internal temperature reaches its "Curie" point or an anomaly temperature at which time its resistance increases abruptly along with an increase of its temperature. Therefore, the temperature of the PTCR was increased in response to current flow therethrough to the ~3-~C-5010 1, auxiliary winding means duxing the startiny operation of the ,, prime mover, and generally at th~ time the prlme mover attained its preselected speed, the registance of the PTCR abruptly increased to a valu~ appreciably limltlng current flow there-through Thua, the auxiLiary winding means was, in effect, rendered generally ineffective in the winding aircuit generally at the time the prime mover attained its preselected speed, and the prime mover remained eneryized generally at the preselected speed thereof in response to the continued excitation of the main winding means. Of course, so long as the PTCR is energized, it will remain "hot" exhibiting a high resistance to current flow, and it is believed that, under certain conditions, this may be a disadvantageous or undesirable feature.
For instance, if for some reason the prime mover had not been energized to the preselected speed so that the torque of the ~
main winding means alone would sustain such preselected speed, `
then the prime mover would stall to zero speed and remain there since the PTCR would, in effect, block current flow to the auxiliary winding means. If an overload protection system of the prime mover did not alleviate the aforementioned stalled condition or locked rotor condition of the prime mover or if such overload protection system did not reset itself before the PTCR had time to cool, this stalled condition of the prime mover would be perpetuated.
In the event the winding circuit of the prime mover was provided with run and/or start capacitors so that the PTCR
was subjected to continuous voltage stress, it is believed that at least one disadvantageous or undesirable feature of this arrangement i5 that the PTCR may be subjected to voltage stress which may exceed the oversurface break down characteristic ,' 0~-~C-501~ ' . .
of the PTCR; there~ore~ ~8 a re9ult of this situatlon, it t~
may have been necessary ~o provide the PTCR with a rather ,' complicated and expensi~e external lnsulation syskem to inhiblt such oversurface break down character~stics which, of course, is also believea to be a disadvantageous ox undesirable feature.
In addition to the foregoing, if "heat sinks", such as metallic fins or other metal masses or the like, were emplo~ed in conjunction with the PTCR to hasten its recovery after it has been deenergized, it is believed that the PTCR
was subjected to thermal stressing having a capacity to physic-ally deteriorate or destroy the PTCR which is, of course, also believed to be a disadvantageous or undesirable eature.
Summary of the Invention ' Among the several objects of the present invention may be noted the provision of an improved prime mover, an improved circuit, an improved method of operating a prime mover, and an improved method of interrupting the operation of means - 20 for inhibiting current flow which overcome at least some of the above discussed disadvantageous or undesirable features, as well as others, of the prior art; the provision of such improved prime mover, circuit and methods in which desirable starting characteristics of the prime mover may be attained along with maximum running eff~ciency thereor~ the provision of such improved prime mover, circuit and methods in which ., , 1 ', 7~B
optimum sized capacitors may be employed with the prime mover; the provision oE such improved prime mover, circuit and methods in which eneryy losses are consèrved; the provision of such improved prime mover, circuit and methods in which a current relay and a PTCR are combined in such a manner as to overcome at least some of the inherent limitations of both such devices; and the provision of such improved prime mover, circuit and methods in which the components thereof are simpIistic, easily assembled or connected, and economically manufactured. These as well as other objects and advantageous features of the present invention will be in part apparent and in part pointed out hereinafter.
In general, a prime mover in one form of the invention is adapted for energization to a preselected speed therefor across a power source, and the prime mover has at least a pair of winding means for excitation to effect the energization of the prime mover generally to the preselected speed when it is energized across the power source. Means is associated with one of the winding means and energized with the prime mover across the power source for inhibiting the excitation of the one winding means generally as the prime mover attains its preselected speed, and means is operable generally in response to a preselected condition associated ~ith the excitation of the other of the winding means and indicative of the occurrence of the preselected speed of the prime mover for effecting the deenergization of the inhibiting means generally as the prime mover attains its preselected speed.
Also in general and in one form of the invention, a circuit is provided for effecting the energization of a prime mover to a preselected speed therefor across a power source.
In this circuit, a pair of parallel circuit branches are adapted for connection across the power source, and the prime mover includes main winding means and auxi~ary winding means respectivel~
connected in the circuit branches for excitation to effect the ~ 03-~C~5010 energization of the prime mover to its preselected sp~ed. Means associated with one of the circuit branches is operable. Generall~
for inhibitiny current flow therethrough to the auxiliary winding means generally as the prime mover attains its preselec-ted speed, and means is operable generally in response to a preselected condition occurring in the other of the circuit branches when the prime mover attains its preselected speed for opening the one circuit branch across the power source to interrupt the operation of the inhibiting means.
Further in general, a method is provided on one form of the invention for operating a prime mover having at least a pair of winding means adapted for excitation across a power source during a starting mode energization of the prime mover and with at least one of the windin~ means of the at least winding means pair adapted for excitation across the power source during a running mode energization of the prime mover.
In this method, a means for inhibiting current flow therethrough to the other of the winding means of the at least winding means pair is energized so as to terminate the starting mode energization of the prime mover, and the continued excitation of the at least one winding means is effected across the power source during the running mode energization of the prime mover. The inhibiting means is placed in open circuit relation with respect to the power source during the running mode energization of the prime mover to effect the deenergization of the inhibition means.
Still in general and in one form of the invention, there is provided a method of interrupting the operation of means for inhibiting current flow therethrough to one of at least a pair of winding means of a winding circuit in a prime mover generally upon the energization thereof to a preselected speed in response to the excitation of the winding ~ 03-~C~5~10 circuit across the power source. This method comprises sensing a preselected con~ition in the win~iny circuit generally - indicative of the occurrence of the preselected speed of the prime mover and opening a circuit between the prime mover and the one winding means to effect the interruption of the operation of the inhibiting means generally as the prime mover is energized to its preselected speed.
FIGS. 1-8 are schematic diagrams respectively showing a prime mover and a circuit therefor each in one form of the invention and illustrating principles which may ~e employed in practicing a method of operating a prime mover and a method of interrupting the operation of means for inhibiting current flow also in one form of the invention, respectively.
Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.
The exemplifications set out herein illustrate the preferred embodiments of the present invention in one form thereof, and such exemplifications are not to be construed as limiting in any manner the scope of the invention or the disclosure thereof.
Referring now to the drawings in general, there is illustrated in one form of the invention a method of operating a prime mover, such as a dynamoelectric machine or electric motor indicated at 11, 13, 15, 17 respectively, having at least a pair parallel connected winding means, such as main winding means 27 and auxiliary winding means 29, adapted for excitation in circuit relation across a pGwer source, such as line terminals _ g _ . ~
Ll, L2, during a startlny mode operatlon of the prime mover to ;s eEfect the energiza~ion ~ the prime mover to a preselected speed therefor (FXGS, 1-8~. In this mekhod, excitation of auxiliary winding means 29 is inhibit~d or ~
otherwise interrupted or terminated generally as prime mover ', 11-17 attains its pxeselected speed when it is energized ' across power source Ll, L2. Then, auxiliary wlnding means f' 29 is placed in open circuit relation with respect to power ,, source Ll, L2 so that prime mover 11-17 is energized ln a running mode with at least main winding means 27 excited to continue the energization of prime mover 11-17 in the running mode thereof across the power source.
More particularly and with specific reference to FIG.
1, an on-off type switch 31 is connected in a circuit, indicated generally at 33 for placing or connecting prime mover 11, such as a resistance start induction run type electric motor for instance, across power source Ll, L2. When switch 31 is moved to its closed or on position by an operator to ' effect the starting operation t mode or time period of prime mover 11, main winding means 27 and auxiliary winding means 29 ' thereof are excited in circuit relation with the power source.
When prime mover 11 is so energized across power source Ll, L2 so as to initiate the starting mode of the prime mover, a - ' ~ rather high current i5 initially drawn ~hcr-efrom through one of a pair of parallel connected branches 35, 37 of circuit 33 in response to the excitation of main winding means 27, and the circuit branches are respectively associated or connected with main windin~ ~e~ns 27 and auxiliary winding means 29. A
coil 39 o a curren~ relay device 41 is sensitive or responsive ~' to the, initial rather high current draw by main winding means 27 ()3-~C-501~ I
, ~, to magnetically e~ect the alosure o contact means, siuch as ~;
contact p~irs 43 o~ the relay d~vice, in circuit branch 37 ~', to effect the flow ~r draw oP current therethrough ko auxiliary ,;~
windiny means 29 so aS to excite it generally sirnultane~usly with the excitation of the main wlnding means.
A solid state means, such as a positive temperature coefficient resistor 45 (hereinafter referred to as a PTCR) has a characteris~ic o~ increasing its temperature in response to current flow therethrough, and when the temperature attains a "Curie" point or anomaly point, the resistance of the PTCR
increases abruptly from a generally low value to a value which, in effect, throttles or inhibits the flow of current through the PTCR. Of course, the current flow inhibiting or throttling effect of PTCR 45 may be timed so as -to generally coincide with the attainment of the preselected speed by prime mover 11 upon the initiation of the starting mode or operation thereof, as described above. Therefore, when relay contact means 43 are closed, PTCR 45 is energized in response to current drawn through circuit branch 37 in response to the excitation of auxiliary winding means 29, and upon such energization, `
the resistance of the PTCR is increased to a value great ::
enough to inhibit, i.e. in effect to-reduce to a generally insignificant value, the current flow therethrough to the auxiliary winding means generally when prime mover 11 is energized to its preselected speed. In this manner, the current flow inhibiting action of PTCR 45 renders auxiliary winding means 29 generally ineffective or unexaited when prime mover 11 attains its pxeselected speed generally at the end of the starting period or operation thereof, and when the auxiliary winding means is thus rendered generally ~neffective, main , winding means 27 remains ~xcit~d in circuit relation with power source Ll, L2 so as to contl~u~ the energization of prime s mover 11 at its pregelected speed cluriny ~he running op ration, ~' mode, or period thereo~
When the running mode o prime mo~er 11 is thus effected at the preselected gpeed thereof, the current draw by the excitation of main winding means 27 i.s, of course, appreciably reduced, and relay device 41 or coil 39 thereof senses or is respongive to such reduction of current draw or current flow in circuit branch 35. Upon sensing the reduced current flow, relay device 41 drops out, i.e. acts to effect the opening o~ its contact means 43 in circuit branch ~., 50 as to place auxiliary winding means 29 in open circuit relation with respect to power source Ll, L2. Further, the afore- :
mentioned opening of relay contact means 43 also effects the deenergization of PTCR 45 thereby to permit the cooling thereof in anticipation of a subsequent starting operation of prime mover 11. Of course, in order to effect the deenergization of prime mover 11 so as to terminate the running mode thereof, switch 31 may be manually moved to its open position thereby to break circuit 33 across power source Ll, L2.
Referring again to the drawings in general and re- !
capitulating at least in part with respect to the ~oregoing, prime mover 11-17 in one form of the inventio~ is adapted for energization to at least the preselected speed across power source Ll, L2 during a starting mode and thereafter in a running mode, and main winding means 27 and auxiliary winding ~ 03-~C~50~0 means 29 of the prime mover are adapted for excitation so as to effect the energization of the prime mover (FIGS. 1-8).
In combination with prime mover 11-17, means, such as a starting device 51 or the like including PTC~ 45, is operable generally during the starting mode operation of the prime mover 11, 13, 15, 17, means, such as a starting device 51 or the like including PTCR 45, is operable generally during the starting mode operation of the prime mover 11, 13, 15, 17 for inhibiting the excitation of auxiliary winding means 29 generally when the preselected speed of prime mover 11, 13, 15, 17 is attained, and means, such as relay device 41 is operable generall~ or actuated upon the occurrence of a preselected condition associated with main winding means 27 for rendering the inhibiting means or starting device deenergized or disabled, i.e. for effecting the deenergization of PTCR 45, when the preselected speed of the prime mover is attained so that excitation of at least the main winding means is continued during the running mode of the prime mover (FIGS. l-8~.
More particularly and with specific reference to FIG. 1, prime mover 11 has a stationary assembly, such as at least a stator 47, and a rotatable assembly, such as at least a rotor 49, adapted to be rotatably mounted in the stationary assembly. ~ain winding means 27 and auxiliary winding means 29 are wound or otherwise disposed on stationary assembly 47 in phase relation, i.e. spaced apart a predetermined number of electrical degrees for starting torque purposes, so as to define a winding circuit 53 for the prime mover, and rotatable assembly 47 is rotatably driven in the stationary assembly in magnetic coupling relation with the main winding means and the auxiliary winding means upon the excitation thereof when prime mover 11 is energized across power source Ll, L2. One of a pair of opposite lead out or terminal connection ends or end portions of main winding means 27 and auxiliary winding , 03~C-5010 I' me~ns 29 are respectively connected together,in parallel circuit relation with a pr~me mover terminal 55, and the other of the opposite lead out ~nd portion pairs o~ the main winding ~,, means and the auxillary winding means are respectfully ,~
connected with another pair of prime mover terminals 57, 59.
Of course, prime mover terminals 55, 57, 59 may be disposed for external connection across power source Ll, ~ ,.
L2 in any one of a plurality of constructions. For instance, terminals 55, 57, 59 may be mounted to a terminal board ':
(not shown)-either interiorly of prime mover 11, or may be :
accessible through a conduit box, or the like, or .in the ,-case of an "open" motor or the like, such terminals are xeadily accessible. Further, if prime mover 11 is a hermetic- . .
, type which may be hermetically sealed within a casing or jacket , .-of a prime mover driven mechanism, such as a compressor or the like for instance, then prime mover terminals 55, 57, 59 may be male terminals clustered together in a Fus.ite plug or the like (not shown) mounted in such jacket so as to be accessible exteriorly thereof. Depending upon the type and arrangement of terminals 55, 57, 59 utilized in prime mover 11, relay device .
41 and starting device 51 may be electricalIy interconnected with each other and terminals 57, 59 by a plurality of leads . having quick connect or disconnect fittings (not shown) so as to be "hung" from prime mover 11 on such lead plurality.
Alternatively, relay device 41 and starting device 51 may be plugged into each other in a so-called "piggyback" mounting arrangement with one of the relay device and starting device being plugged onto terminals 57, 59. Of course~ this ,, "piggyback" mounting arrangemen,t of relay device 41 and starting device 51 may also ~e "h~ng" onto prime mover 11 by the electrlcal - , , , ' , ~ ~~4~ ~.
~ ~ * ~ 03~AC-5010 ',, leads havin7 ~uick connect ~tt~ng~ a~ ~reviously mentioned.
It is contemplated that ~arious other moun~ing arrangementS
may be utilized to mount relay device 41 and starting device h 51 to prime mover terminals 57, 59 within the scope of the '~
invention so as to meet the objects thereof.
Relay device 41 may be a current relay, such as model !~
3ARR12 available from the General Electric Company, Morrison, Illinois. Coil 39 of relay device l!s serially connected between line terminal Ll and prime mover terminal 59, and upon energization of prime mover 11 across power source Ll, - L2 upon the manual closure of switch 31, as previously discussed, the relay coil senses or is operated or energized in response - to the current draw of main winding means 27 to magnetically effect the movement of contact means 43 of the relay device - 15 to their closed position in circuit branch 37. Since relay contact means 43 are serially connected between line terminal Ll of power source Ll, L2 and starting device 51, the actuation ;-or operation of relay device 41 to effect the closure of its contact means 43 in response to current draw through relay coil 39 effects the energization of starting device 51 which is seriaLly connected between the relay contact means and prime mover terminal 57. Of course, the excitation of relay coil 39 when prime mover 11 is initially placed across power source Ll, L2 is in response to a preselected current draw ~- 25 referred to as the pick-up calibration o~ relay device .
~ 03~AC-5010 and the rela~ coil is, of course, deeneryized in response to a preselected low current draw referred to as the drop-out calibration of the relay device. Of course, the low current draw or drop-out current which relay coil 39 senses or is operated in response to generally defines the afore-mentioned preselected condition, as discussed in greater detail hereinafter. If greater details of the operation and/or construction of relay device 41 is desired, reference may be had to U.S. Patent No. 3,130,284 issued to Lee O. Woods on April 21, 1964. Of course, it is contemplated that devices other than relay device 41 may be utilized in the present invention so as to meet at least some of the objects and advantageous features thereof.
Starting device 51 connects its PTCR 45 is series circuit relation between contact means 43 of relay device 41 and prime mover terminal 57; therefore, as previously mentioned, ~e resistance of PTCR in response to the current applied thereto from power source Ll, L2 through the closed relay contact means 43 causes the PTCR to heat during the initial stages of the current flow therethrough, i.e., during the starting operation or period of prime mover 11. When PTCR 45 is so heated to its "Curie" point temperature or anomaly temperature, its resistance abruptly increases in opposition to current flow therethrough. Of course, upon attaining the anomoly temperature, the high resistance of PTCR 45 does not block further current flow but instead limits it to a value which is low enough to, in effect, render auxiliary winding means 29 ineffective or disabled in winding circuit 53 of prime mover 11. If greater details of the operation and/or construction of starting device 51 ~ 3-AC~501r) is desired, reference may be had to the Lee o. Woods et al U.S. Patent No. ~ / dated ~J~Ce~;r,~
Of course, it is contemplated that devices other than starting device 51 may be u-tilized in the present invention so as to meet at least some of the objects and advantageous features thereof.
To complete the description of prime mover 11 and its associated components, an overload protector device 60 which includes a current carrying thermal responsive switch or switch means 61, such as a bimetal element for instance, may be connected in series relation between circuit branches 35, 37 and line terminal L. In the event of a current over-load situation in the operation of prime mover 11, protector device 61 is responsive to a preselected thermal condition which accompanies such current overload to open circuit means 33 thereby to interrupt the energization of prime mover 11 across the line. Upon cooling, protector device 61 will effect the reenergization of prime mover 11 across power source Ll, L2 assuming, of course, that the overload situation has been alleviated. Overload protector 60 may be a model 3ARGll available from the General Electric Company, Morrison, Illinois. If greater details of the operation and/or construction of protector device 60 is desired, reference may be had to U.S. Patent No.3,361,890 issued on January 2, 1968 to Donald H. Stoll. Further, it may be noted that because PTCR 45 provides protection for auxiliary winding means 29 by limiting the current flow to it, overload protector device 60 may be designed or rated specifically for the protection of only main 03 -AC-501a ~7~815 ~;
;, "
~inding meins 27; ~exe~ore, in this m~nner~.the applicat.ion o~ the protector dev.~ae i3 belteverl to be ~impl~fied so as to eliminate compromlses wh~ch miyht otherwise be made in order ~' to provide current overload protection for the auxiliary winding ,.
means as well as the main windlng means, In the operation of prime mover 11, switch 31 is manually closed thereby to make circuit means 33 across the :
prime mover placing it in its starting mode so that main winding means 27 and auxiliary winding means 29 may be initially excited. Current flows in circuit rneans 33 from line terminal Ll to parallel circuit branches 35, 37, and with respect to circuit branch 35, current passes through coil 39 of relay device 41, terminal 59 of prime mover 11, its main winding means 27 and terminal 55 to line terminal L2. Of course, upon the initial exci~ation of main winding means 27, a generally high current draw is occasioned through circuit branch 35, and when such current draw excites coil 39 of relay .
device to the predetermined pick-up value therefor, the coil magnetically effects the movement of its associated contact means 43 from its at-rest or open position thereof to its closed position in making engagement so as to compleke or make circuit ::
branch 37 across line terminals.Ll, L2 generally simultaneously with the completion of branch circuit 35 across the line terminals, as previously described. When relay device 41 is ~o energized to effect the closure of its contact means 43, ' .
. -18- ,.
~ 03-~C-5010 current flows in circuit branch 37 through the closed relay con~act means 43, PTCR 45 of startiny device 51, terminal 57 of prime mover 11, its auxiliary winding mean~ 29 and terminal 55 to line terminal L2. In this manner, prime mover 11 is energized in its starting mode across line terminals Ll, L2 so as to initially effect the generally simultaneous excitation of both main winding means 27 and auxiliary windiny means 29 of the prime mover, and upon such energization of the prime mover, rotatable assembly 49 is rotatably driven in stationary assembly 47 due to the magnetic coupling relation between the rotatable assembly and both the main winding means and the auxiliary winding means.
During the starting time period of prime mover 11, i.e. the period o~ time consumed in bringing rotatable assembly 49 from a stand-still position to its preselected speed, PTCR 45 is energized by the current draw of auxiliary winding means 29 through circuit branch 37, and generally about the time rotatable assembly 49 attains its preselected speed, i.e., generally at the end of the starting time period of the prime mover, the PTCR becomes heated to its anomaly temperature with the accompanying increase in the resistance thereof so as to inhibit current flow to auxiliary winding means 29 of the prime mover. In this manner, the inhibition of current flow by PTCR
45 generally as rotatable assembly 49 attains its preselected speed renders auxiliary winding means 29 generally ineffective in winding circuit 53 of prime mover 11. Thereafter, prime mover 11 is energized in its running mode generally at the preselected speed across the line terminals Ll, L2 in response to the continued excitation of main winding means 27 in circuit relation with the line terminals.
~ - 19 -03~AC-501(J ~, IL75~8 "!
As xotatable asser~ly 49 attains.. its preselected j, speed so that prime mo~er 11 i6 transl~ted from its starting ~,, mod~ to ~ts running mode, as described above, an appreciable i~
reduction of the current draw by main winding means 27 is ~
occasioned. Of course, the occurrence of this current draw reduction, i.e. the a~orementioned pxeselected condition, r'' in circuit branch 35 is, in effect, sensed by coil 39 of relay ~3vice 41, and when the current draw is so reduced to the predetermined drop-out value o~ the relay device, the magne~ic affect and excitation of the coil is correspondingly reduced so as to permit the reopening of its associated .. contact means 43. Upon ~he reopening of relay contact means 43, branch circuit 37 is placed in open circuit relation with respect to line terminals Ll, L2, i.e., interrupted or opened thereacross, so as to obviate current flow through branch circuit 37 to starting device 51 and deenergize PTCR 45.
Of course, this deenergization of PTCR 45 not only alleviates any voltage drop across it but also permits it to cool in anitcipation of a subsequent starting operation of prime mover 11.
With reference again in general to the drawings and recapitulating at least in part with respect to the fore~
going, circuit means 33 in one fo~m of the invent.ion is adapted for connection across power source Ll~ L2 so as to control the energization of prime mover 11 having main winding means 27 .
and auxiliary winding means 29 adapted for excitation in parallel circuit relation with each other (.FIGS, 1~8). Means, such.~s starting device 51 including PTCR 45, is coupled in serieg ctrcu~t relation with auxiliary winding means 29 for inhibiting the excitation thereof generally at a preselected : ' .' . '.' ~~~ ;, . 03~AC-SOL7 7~,~
t speed prime mover 11~ an~ me~n~, suc~ a~S rela~ device 41, is r~
operahle generally ~n resporr~e to a pregelected condition ~
associated with the exaltation o~ main winding means 27 ~:
for disassociatiny the inhibiting means or start~ng device S from circuit relation with power source Ll, L2 (FIGS. 1-8).
Referrinsg now to FIG. 2, prime mover 13 is shown functioning in circuit means 33 and operated by the above described method generally in the same manner as the previously described prime mover 11 with the exceptions discussed hereinafter, and it is believed that prime mover 13 functioning in combination with ~he components of circuit means 33 attains indigenous objects and advantageous features as well as meeting at least some of those set out hereinbefore.
Prime mover 13 is a capacitor start induction run type, and a start capacitor 63 is illustrated as being serially connected in circuit relation between auxiliary winding means 29 and starting device 4~. If desired, start capacitor 63 may be an integral or permanent part of winding circuit 53 of prime mover 13, or alternatively the starting capacitor may be "hung" or electrically connected between prime mover terminal 57 and starting device 51 by the use of a plurality of leads having quick connect fittings, as previously mentioned.
Start capacitor 63 is utilized in prime mover 13 to improve the starting torque thereof, as is known in the art, and since . 25 circuit branch 37 is opened by relay device 41 generally as :.
'.
-21- '~
' 03-AC~5010 ' ;~
'7~ 3 "t';~
~', prime mover 13 attains its pre~elected 3,peed generally at the '"', end of its~startlng mode or period, as previously discussed, ~,, the start capacitor will digcharge through auxlliary winding means 2~. Thus, it may be noted that the si~e of start capacitor 63 may be opt,imized with respect to prime mover 13 so as to provide maximum starting torque values therefor.
In FIG. 3, prime mover 15 is shown functioning in circuit means 33 and operated by the above described method generally in the same manner as the previously described prime mover 11 with the exceptions discussed below, and it is ; believed that prime mover 15 functioning in combination with components of circuit means 33 attains indigenous objects and advantageous features as well as meeting at least some of those set out hereinbefore. ', Prime mover l5 is a resistance start capacitor run type, and a run capacitor 65 i5 connected in winding circuit 53 '' of the prime mover between terminals 51, 59 thereof. Of ~ course, run capacitor 65 is provided to improve the efficiency ; of prime mouer 15 by effecting the utilization of auxiliary winding means 27 during the running mode operation of the prime mover, as isknown in the art, and since circuit branch 37 is opened by relay device 41 generally as prime mover 15 attains its preselected speed generally at the end of its starting mode or period, as previously discussed, the run -, 25 capacitor,will discharge through winding circuit 53 o the prime mover. Thus~ it may be noted that the size of run :
capacitor 65 may be optimized with respect to prime mover 15 ';-, so as to provide maximum running efficiency therefor.
In FIG. 4, prime mover 17 is shown functioning in circuit means 33 and operating in accordance with the above 03-~C-501 ~L~3L7'58~3 described method generally in the ~ame manner as previously '' described pr~me mover 11 wlth the exaeptions d~5cussed below, and it is belleved that prime maver ~ fanationing in com~in~ '' ation with components o circuit meang 33 atta~ns indigenous ~, objects and advantayeous features as well as meetiny at least - some o~ those set out hereinbefore.
Prime mover 17 is a capacitor start capacitor run type. Run capacitor 65 is connected between prime mover ;
terminals 57, 59 t and start capacitor 63 is serially connected in circuit relation between starting device 51 and prime mover terminal 57. As previously mentioned, start capacit:or 63 may either be an integral part or component of prime mover 17 or may be "hung" thereon by suitable electrical leads having ;
qui~k connect fittings. As well known in the art, run capac~
itor 65 is utilized to improve running efficiency of prime mover 17 by effecting the utilization of auxiliary winding ,~
means 27 during the running mode of the prime mo~ér, and start capacitor 63 provides increased starting torque during the starting mode of t~e prime mover. Of course, circuit branch 37 is opened by relay device 41 generally as prime mover 17 attains its preselected speed generally at the end of its starting mode or period, as previously discussed and continued excitation of main winding means 27 along with ~ auxiliary winding means 29 through capacitor 65 energizes ^ 25 the prime mover in its running mode. In this particular prime mover construc~ion, start capacitor 63 will either discharge internally or through PTCR 45 when relay contact means 43 axe closed in branch circuit 37, and run capacitor 65 will discharge through wind~ng circuit 53 of prime mover 17. Thus~ it may be noted that tne s~zes o~ capacitors 63, 65 may be optimized with -23- :
~,
to its preselected speed, ~he current d~aw of the main winding means was appreciably reduc~d, an~ such reduction of current caused the relay coil to weaken its magnetic affect thereby to permit the contact means of the current relay to return to their at-rest or open position. Thus, with the relay contacts so opened to interrupt current flow to the auxiliary winding means, the auxiliary winding means were rendered ineffective generally at the time the prime mover attains its preselected speed, and the prime mover - lO remained energized generally at the preselected speed thereof during its~running mode in response to the continued excitation of the main winding means. At least one of the disadvantageous or undesirabIe features of such past prime movers utilizing a current relay for controlling excitation of the auxiliary winding means is believed to be that the contact means of the current relay had a tendency to weld in response to the'generally large current draw by the auxiliary windings during the starting operation of the prime mover.
Another disadvantageous or undesirable feature is believed to be'that the'current reIay generated radio and television interference at the instant of make and break due to arcing of the contact means.
In the event a capacitor was utilizecl in series circuit relation with'the''auxiliary winding of the aforementioned prime mover utilizing the current relay, the starting torque of the such'prime mover may be'increased wherein the capacitor may limit the'amount of current in the auxiliary winding ~ 03-AC-5010 ,' ,,.
to a safe value while electr1cally shiting its phase, l;
Again, however, the aforementloned disadvantage or undesirable feature is bel,ieved to be that the allowable magnitude of the "
current drawn by the auxiliary winding ls limited by the relay contact means to resist welding which may occur when the ~' capacitor is discharged directly through the relay contact ,, means during the starting operation of the prime mover. For instance, if the relay contact means make, break and remake '' during the starting operation of the prime mover, the capacitor may be charged to a peak voltage value, disconnected, and then ' reconnected one hun~red eighty electrical degrees (180) later to a peak opposite polarity line. Thus, the resultant discharge is at double peak value. It is also believed that the use of ' a relatively large capacitor, for maximum starting torque of the aforementioned prime mover utilizing a current relay, may also be impracticable generally for the same reasons as discussed above.
Another one of the prior art devices for controlling the excitation of the auxiliary winding means was a positive temperature coeff.icient resistor (PTCR) which was connected in series with the auxiliary winding of the prime mover. When the prime mover was energized across the line, the main winding means and auxiliary winding means were initially conjointly excited since the PTCR exhibited little initial resistance to ~~ 25 current flow to the auxiliary winding means. The PTCR acts generally as a low value resistor until its internal temperature reaches its "Curie" point or an anomaly temperature at which time its resistance increases abruptly along with an increase of its temperature. Therefore, the temperature of the PTCR was increased in response to current flow therethrough to the ~3-~C-5010 1, auxiliary winding means duxing the startiny operation of the ,, prime mover, and generally at th~ time the prlme mover attained its preselected speed, the registance of the PTCR abruptly increased to a valu~ appreciably limltlng current flow there-through Thua, the auxiLiary winding means was, in effect, rendered generally ineffective in the winding aircuit generally at the time the prime mover attained its preselected speed, and the prime mover remained eneryized generally at the preselected speed thereof in response to the continued excitation of the main winding means. Of course, so long as the PTCR is energized, it will remain "hot" exhibiting a high resistance to current flow, and it is believed that, under certain conditions, this may be a disadvantageous or undesirable feature.
For instance, if for some reason the prime mover had not been energized to the preselected speed so that the torque of the ~
main winding means alone would sustain such preselected speed, `
then the prime mover would stall to zero speed and remain there since the PTCR would, in effect, block current flow to the auxiliary winding means. If an overload protection system of the prime mover did not alleviate the aforementioned stalled condition or locked rotor condition of the prime mover or if such overload protection system did not reset itself before the PTCR had time to cool, this stalled condition of the prime mover would be perpetuated.
In the event the winding circuit of the prime mover was provided with run and/or start capacitors so that the PTCR
was subjected to continuous voltage stress, it is believed that at least one disadvantageous or undesirable feature of this arrangement i5 that the PTCR may be subjected to voltage stress which may exceed the oversurface break down characteristic ,' 0~-~C-501~ ' . .
of the PTCR; there~ore~ ~8 a re9ult of this situatlon, it t~
may have been necessary ~o provide the PTCR with a rather ,' complicated and expensi~e external lnsulation syskem to inhiblt such oversurface break down character~stics which, of course, is also believea to be a disadvantageous ox undesirable feature.
In addition to the foregoing, if "heat sinks", such as metallic fins or other metal masses or the like, were emplo~ed in conjunction with the PTCR to hasten its recovery after it has been deenergized, it is believed that the PTCR
was subjected to thermal stressing having a capacity to physic-ally deteriorate or destroy the PTCR which is, of course, also believed to be a disadvantageous or undesirable eature.
Summary of the Invention ' Among the several objects of the present invention may be noted the provision of an improved prime mover, an improved circuit, an improved method of operating a prime mover, and an improved method of interrupting the operation of means - 20 for inhibiting current flow which overcome at least some of the above discussed disadvantageous or undesirable features, as well as others, of the prior art; the provision of such improved prime mover, circuit and methods in which desirable starting characteristics of the prime mover may be attained along with maximum running eff~ciency thereor~ the provision of such improved prime mover, circuit and methods in which ., , 1 ', 7~B
optimum sized capacitors may be employed with the prime mover; the provision oE such improved prime mover, circuit and methods in which eneryy losses are consèrved; the provision of such improved prime mover, circuit and methods in which a current relay and a PTCR are combined in such a manner as to overcome at least some of the inherent limitations of both such devices; and the provision of such improved prime mover, circuit and methods in which the components thereof are simpIistic, easily assembled or connected, and economically manufactured. These as well as other objects and advantageous features of the present invention will be in part apparent and in part pointed out hereinafter.
In general, a prime mover in one form of the invention is adapted for energization to a preselected speed therefor across a power source, and the prime mover has at least a pair of winding means for excitation to effect the energization of the prime mover generally to the preselected speed when it is energized across the power source. Means is associated with one of the winding means and energized with the prime mover across the power source for inhibiting the excitation of the one winding means generally as the prime mover attains its preselected speed, and means is operable generally in response to a preselected condition associated ~ith the excitation of the other of the winding means and indicative of the occurrence of the preselected speed of the prime mover for effecting the deenergization of the inhibiting means generally as the prime mover attains its preselected speed.
Also in general and in one form of the invention, a circuit is provided for effecting the energization of a prime mover to a preselected speed therefor across a power source.
In this circuit, a pair of parallel circuit branches are adapted for connection across the power source, and the prime mover includes main winding means and auxi~ary winding means respectivel~
connected in the circuit branches for excitation to effect the ~ 03-~C~5010 energization of the prime mover to its preselected sp~ed. Means associated with one of the circuit branches is operable. Generall~
for inhibitiny current flow therethrough to the auxiliary winding means generally as the prime mover attains its preselec-ted speed, and means is operable generally in response to a preselected condition occurring in the other of the circuit branches when the prime mover attains its preselected speed for opening the one circuit branch across the power source to interrupt the operation of the inhibiting means.
Further in general, a method is provided on one form of the invention for operating a prime mover having at least a pair of winding means adapted for excitation across a power source during a starting mode energization of the prime mover and with at least one of the windin~ means of the at least winding means pair adapted for excitation across the power source during a running mode energization of the prime mover.
In this method, a means for inhibiting current flow therethrough to the other of the winding means of the at least winding means pair is energized so as to terminate the starting mode energization of the prime mover, and the continued excitation of the at least one winding means is effected across the power source during the running mode energization of the prime mover. The inhibiting means is placed in open circuit relation with respect to the power source during the running mode energization of the prime mover to effect the deenergization of the inhibition means.
Still in general and in one form of the invention, there is provided a method of interrupting the operation of means for inhibiting current flow therethrough to one of at least a pair of winding means of a winding circuit in a prime mover generally upon the energization thereof to a preselected speed in response to the excitation of the winding ~ 03-~C~5~10 circuit across the power source. This method comprises sensing a preselected con~ition in the win~iny circuit generally - indicative of the occurrence of the preselected speed of the prime mover and opening a circuit between the prime mover and the one winding means to effect the interruption of the operation of the inhibiting means generally as the prime mover is energized to its preselected speed.
FIGS. 1-8 are schematic diagrams respectively showing a prime mover and a circuit therefor each in one form of the invention and illustrating principles which may ~e employed in practicing a method of operating a prime mover and a method of interrupting the operation of means for inhibiting current flow also in one form of the invention, respectively.
Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.
The exemplifications set out herein illustrate the preferred embodiments of the present invention in one form thereof, and such exemplifications are not to be construed as limiting in any manner the scope of the invention or the disclosure thereof.
Referring now to the drawings in general, there is illustrated in one form of the invention a method of operating a prime mover, such as a dynamoelectric machine or electric motor indicated at 11, 13, 15, 17 respectively, having at least a pair parallel connected winding means, such as main winding means 27 and auxiliary winding means 29, adapted for excitation in circuit relation across a pGwer source, such as line terminals _ g _ . ~
Ll, L2, during a startlny mode operatlon of the prime mover to ;s eEfect the energiza~ion ~ the prime mover to a preselected speed therefor (FXGS, 1-8~. In this mekhod, excitation of auxiliary winding means 29 is inhibit~d or ~
otherwise interrupted or terminated generally as prime mover ', 11-17 attains its pxeselected speed when it is energized ' across power source Ll, L2. Then, auxiliary wlnding means f' 29 is placed in open circuit relation with respect to power ,, source Ll, L2 so that prime mover 11-17 is energized ln a running mode with at least main winding means 27 excited to continue the energization of prime mover 11-17 in the running mode thereof across the power source.
More particularly and with specific reference to FIG.
1, an on-off type switch 31 is connected in a circuit, indicated generally at 33 for placing or connecting prime mover 11, such as a resistance start induction run type electric motor for instance, across power source Ll, L2. When switch 31 is moved to its closed or on position by an operator to ' effect the starting operation t mode or time period of prime mover 11, main winding means 27 and auxiliary winding means 29 ' thereof are excited in circuit relation with the power source.
When prime mover 11 is so energized across power source Ll, L2 so as to initiate the starting mode of the prime mover, a - ' ~ rather high current i5 initially drawn ~hcr-efrom through one of a pair of parallel connected branches 35, 37 of circuit 33 in response to the excitation of main winding means 27, and the circuit branches are respectively associated or connected with main windin~ ~e~ns 27 and auxiliary winding means 29. A
coil 39 o a curren~ relay device 41 is sensitive or responsive ~' to the, initial rather high current draw by main winding means 27 ()3-~C-501~ I
, ~, to magnetically e~ect the alosure o contact means, siuch as ~;
contact p~irs 43 o~ the relay d~vice, in circuit branch 37 ~', to effect the flow ~r draw oP current therethrough ko auxiliary ,;~
windiny means 29 so aS to excite it generally sirnultane~usly with the excitation of the main wlnding means.
A solid state means, such as a positive temperature coefficient resistor 45 (hereinafter referred to as a PTCR) has a characteris~ic o~ increasing its temperature in response to current flow therethrough, and when the temperature attains a "Curie" point or anomaly point, the resistance of the PTCR
increases abruptly from a generally low value to a value which, in effect, throttles or inhibits the flow of current through the PTCR. Of course, the current flow inhibiting or throttling effect of PTCR 45 may be timed so as -to generally coincide with the attainment of the preselected speed by prime mover 11 upon the initiation of the starting mode or operation thereof, as described above. Therefore, when relay contact means 43 are closed, PTCR 45 is energized in response to current drawn through circuit branch 37 in response to the excitation of auxiliary winding means 29, and upon such energization, `
the resistance of the PTCR is increased to a value great ::
enough to inhibit, i.e. in effect to-reduce to a generally insignificant value, the current flow therethrough to the auxiliary winding means generally when prime mover 11 is energized to its preselected speed. In this manner, the current flow inhibiting action of PTCR 45 renders auxiliary winding means 29 generally ineffective or unexaited when prime mover 11 attains its pxeselected speed generally at the end of the starting period or operation thereof, and when the auxiliary winding means is thus rendered generally ~neffective, main , winding means 27 remains ~xcit~d in circuit relation with power source Ll, L2 so as to contl~u~ the energization of prime s mover 11 at its pregelected speed cluriny ~he running op ration, ~' mode, or period thereo~
When the running mode o prime mo~er 11 is thus effected at the preselected gpeed thereof, the current draw by the excitation of main winding means 27 i.s, of course, appreciably reduced, and relay device 41 or coil 39 thereof senses or is respongive to such reduction of current draw or current flow in circuit branch 35. Upon sensing the reduced current flow, relay device 41 drops out, i.e. acts to effect the opening o~ its contact means 43 in circuit branch ~., 50 as to place auxiliary winding means 29 in open circuit relation with respect to power source Ll, L2. Further, the afore- :
mentioned opening of relay contact means 43 also effects the deenergization of PTCR 45 thereby to permit the cooling thereof in anticipation of a subsequent starting operation of prime mover 11. Of course, in order to effect the deenergization of prime mover 11 so as to terminate the running mode thereof, switch 31 may be manually moved to its open position thereby to break circuit 33 across power source Ll, L2.
Referring again to the drawings in general and re- !
capitulating at least in part with respect to the ~oregoing, prime mover 11-17 in one form of the inventio~ is adapted for energization to at least the preselected speed across power source Ll, L2 during a starting mode and thereafter in a running mode, and main winding means 27 and auxiliary winding ~ 03-~C~50~0 means 29 of the prime mover are adapted for excitation so as to effect the energization of the prime mover (FIGS. 1-8).
In combination with prime mover 11-17, means, such as a starting device 51 or the like including PTC~ 45, is operable generally during the starting mode operation of the prime mover 11, 13, 15, 17, means, such as a starting device 51 or the like including PTCR 45, is operable generally during the starting mode operation of the prime mover 11, 13, 15, 17 for inhibiting the excitation of auxiliary winding means 29 generally when the preselected speed of prime mover 11, 13, 15, 17 is attained, and means, such as relay device 41 is operable generall~ or actuated upon the occurrence of a preselected condition associated with main winding means 27 for rendering the inhibiting means or starting device deenergized or disabled, i.e. for effecting the deenergization of PTCR 45, when the preselected speed of the prime mover is attained so that excitation of at least the main winding means is continued during the running mode of the prime mover (FIGS. l-8~.
More particularly and with specific reference to FIG. 1, prime mover 11 has a stationary assembly, such as at least a stator 47, and a rotatable assembly, such as at least a rotor 49, adapted to be rotatably mounted in the stationary assembly. ~ain winding means 27 and auxiliary winding means 29 are wound or otherwise disposed on stationary assembly 47 in phase relation, i.e. spaced apart a predetermined number of electrical degrees for starting torque purposes, so as to define a winding circuit 53 for the prime mover, and rotatable assembly 47 is rotatably driven in the stationary assembly in magnetic coupling relation with the main winding means and the auxiliary winding means upon the excitation thereof when prime mover 11 is energized across power source Ll, L2. One of a pair of opposite lead out or terminal connection ends or end portions of main winding means 27 and auxiliary winding , 03~C-5010 I' me~ns 29 are respectively connected together,in parallel circuit relation with a pr~me mover terminal 55, and the other of the opposite lead out ~nd portion pairs o~ the main winding ~,, means and the auxillary winding means are respectfully ,~
connected with another pair of prime mover terminals 57, 59.
Of course, prime mover terminals 55, 57, 59 may be disposed for external connection across power source Ll, ~ ,.
L2 in any one of a plurality of constructions. For instance, terminals 55, 57, 59 may be mounted to a terminal board ':
(not shown)-either interiorly of prime mover 11, or may be :
accessible through a conduit box, or the like, or .in the ,-case of an "open" motor or the like, such terminals are xeadily accessible. Further, if prime mover 11 is a hermetic- . .
, type which may be hermetically sealed within a casing or jacket , .-of a prime mover driven mechanism, such as a compressor or the like for instance, then prime mover terminals 55, 57, 59 may be male terminals clustered together in a Fus.ite plug or the like (not shown) mounted in such jacket so as to be accessible exteriorly thereof. Depending upon the type and arrangement of terminals 55, 57, 59 utilized in prime mover 11, relay device .
41 and starting device 51 may be electricalIy interconnected with each other and terminals 57, 59 by a plurality of leads . having quick connect or disconnect fittings (not shown) so as to be "hung" from prime mover 11 on such lead plurality.
Alternatively, relay device 41 and starting device 51 may be plugged into each other in a so-called "piggyback" mounting arrangement with one of the relay device and starting device being plugged onto terminals 57, 59. Of course~ this ,, "piggyback" mounting arrangemen,t of relay device 41 and starting device 51 may also ~e "h~ng" onto prime mover 11 by the electrlcal - , , , ' , ~ ~~4~ ~.
~ ~ * ~ 03~AC-5010 ',, leads havin7 ~uick connect ~tt~ng~ a~ ~reviously mentioned.
It is contemplated that ~arious other moun~ing arrangementS
may be utilized to mount relay device 41 and starting device h 51 to prime mover terminals 57, 59 within the scope of the '~
invention so as to meet the objects thereof.
Relay device 41 may be a current relay, such as model !~
3ARR12 available from the General Electric Company, Morrison, Illinois. Coil 39 of relay device l!s serially connected between line terminal Ll and prime mover terminal 59, and upon energization of prime mover 11 across power source Ll, - L2 upon the manual closure of switch 31, as previously discussed, the relay coil senses or is operated or energized in response - to the current draw of main winding means 27 to magnetically effect the movement of contact means 43 of the relay device - 15 to their closed position in circuit branch 37. Since relay contact means 43 are serially connected between line terminal Ll of power source Ll, L2 and starting device 51, the actuation ;-or operation of relay device 41 to effect the closure of its contact means 43 in response to current draw through relay coil 39 effects the energization of starting device 51 which is seriaLly connected between the relay contact means and prime mover terminal 57. Of course, the excitation of relay coil 39 when prime mover 11 is initially placed across power source Ll, L2 is in response to a preselected current draw ~- 25 referred to as the pick-up calibration o~ relay device .
~ 03~AC-5010 and the rela~ coil is, of course, deeneryized in response to a preselected low current draw referred to as the drop-out calibration of the relay device. Of course, the low current draw or drop-out current which relay coil 39 senses or is operated in response to generally defines the afore-mentioned preselected condition, as discussed in greater detail hereinafter. If greater details of the operation and/or construction of relay device 41 is desired, reference may be had to U.S. Patent No. 3,130,284 issued to Lee O. Woods on April 21, 1964. Of course, it is contemplated that devices other than relay device 41 may be utilized in the present invention so as to meet at least some of the objects and advantageous features thereof.
Starting device 51 connects its PTCR 45 is series circuit relation between contact means 43 of relay device 41 and prime mover terminal 57; therefore, as previously mentioned, ~e resistance of PTCR in response to the current applied thereto from power source Ll, L2 through the closed relay contact means 43 causes the PTCR to heat during the initial stages of the current flow therethrough, i.e., during the starting operation or period of prime mover 11. When PTCR 45 is so heated to its "Curie" point temperature or anomaly temperature, its resistance abruptly increases in opposition to current flow therethrough. Of course, upon attaining the anomoly temperature, the high resistance of PTCR 45 does not block further current flow but instead limits it to a value which is low enough to, in effect, render auxiliary winding means 29 ineffective or disabled in winding circuit 53 of prime mover 11. If greater details of the operation and/or construction of starting device 51 ~ 3-AC~501r) is desired, reference may be had to the Lee o. Woods et al U.S. Patent No. ~ / dated ~J~Ce~;r,~
Of course, it is contemplated that devices other than starting device 51 may be u-tilized in the present invention so as to meet at least some of the objects and advantageous features thereof.
To complete the description of prime mover 11 and its associated components, an overload protector device 60 which includes a current carrying thermal responsive switch or switch means 61, such as a bimetal element for instance, may be connected in series relation between circuit branches 35, 37 and line terminal L. In the event of a current over-load situation in the operation of prime mover 11, protector device 61 is responsive to a preselected thermal condition which accompanies such current overload to open circuit means 33 thereby to interrupt the energization of prime mover 11 across the line. Upon cooling, protector device 61 will effect the reenergization of prime mover 11 across power source Ll, L2 assuming, of course, that the overload situation has been alleviated. Overload protector 60 may be a model 3ARGll available from the General Electric Company, Morrison, Illinois. If greater details of the operation and/or construction of protector device 60 is desired, reference may be had to U.S. Patent No.3,361,890 issued on January 2, 1968 to Donald H. Stoll. Further, it may be noted that because PTCR 45 provides protection for auxiliary winding means 29 by limiting the current flow to it, overload protector device 60 may be designed or rated specifically for the protection of only main 03 -AC-501a ~7~815 ~;
;, "
~inding meins 27; ~exe~ore, in this m~nner~.the applicat.ion o~ the protector dev.~ae i3 belteverl to be ~impl~fied so as to eliminate compromlses wh~ch miyht otherwise be made in order ~' to provide current overload protection for the auxiliary winding ,.
means as well as the main windlng means, In the operation of prime mover 11, switch 31 is manually closed thereby to make circuit means 33 across the :
prime mover placing it in its starting mode so that main winding means 27 and auxiliary winding means 29 may be initially excited. Current flows in circuit rneans 33 from line terminal Ll to parallel circuit branches 35, 37, and with respect to circuit branch 35, current passes through coil 39 of relay device 41, terminal 59 of prime mover 11, its main winding means 27 and terminal 55 to line terminal L2. Of course, upon the initial exci~ation of main winding means 27, a generally high current draw is occasioned through circuit branch 35, and when such current draw excites coil 39 of relay .
device to the predetermined pick-up value therefor, the coil magnetically effects the movement of its associated contact means 43 from its at-rest or open position thereof to its closed position in making engagement so as to compleke or make circuit ::
branch 37 across line terminals.Ll, L2 generally simultaneously with the completion of branch circuit 35 across the line terminals, as previously described. When relay device 41 is ~o energized to effect the closure of its contact means 43, ' .
. -18- ,.
~ 03-~C-5010 current flows in circuit branch 37 through the closed relay con~act means 43, PTCR 45 of startiny device 51, terminal 57 of prime mover 11, its auxiliary winding mean~ 29 and terminal 55 to line terminal L2. In this manner, prime mover 11 is energized in its starting mode across line terminals Ll, L2 so as to initially effect the generally simultaneous excitation of both main winding means 27 and auxiliary windiny means 29 of the prime mover, and upon such energization of the prime mover, rotatable assembly 49 is rotatably driven in stationary assembly 47 due to the magnetic coupling relation between the rotatable assembly and both the main winding means and the auxiliary winding means.
During the starting time period of prime mover 11, i.e. the period o~ time consumed in bringing rotatable assembly 49 from a stand-still position to its preselected speed, PTCR 45 is energized by the current draw of auxiliary winding means 29 through circuit branch 37, and generally about the time rotatable assembly 49 attains its preselected speed, i.e., generally at the end of the starting time period of the prime mover, the PTCR becomes heated to its anomaly temperature with the accompanying increase in the resistance thereof so as to inhibit current flow to auxiliary winding means 29 of the prime mover. In this manner, the inhibition of current flow by PTCR
45 generally as rotatable assembly 49 attains its preselected speed renders auxiliary winding means 29 generally ineffective in winding circuit 53 of prime mover 11. Thereafter, prime mover 11 is energized in its running mode generally at the preselected speed across the line terminals Ll, L2 in response to the continued excitation of main winding means 27 in circuit relation with the line terminals.
~ - 19 -03~AC-501(J ~, IL75~8 "!
As xotatable asser~ly 49 attains.. its preselected j, speed so that prime mo~er 11 i6 transl~ted from its starting ~,, mod~ to ~ts running mode, as described above, an appreciable i~
reduction of the current draw by main winding means 27 is ~
occasioned. Of course, the occurrence of this current draw reduction, i.e. the a~orementioned pxeselected condition, r'' in circuit branch 35 is, in effect, sensed by coil 39 of relay ~3vice 41, and when the current draw is so reduced to the predetermined drop-out value o~ the relay device, the magne~ic affect and excitation of the coil is correspondingly reduced so as to permit the reopening of its associated .. contact means 43. Upon ~he reopening of relay contact means 43, branch circuit 37 is placed in open circuit relation with respect to line terminals Ll, L2, i.e., interrupted or opened thereacross, so as to obviate current flow through branch circuit 37 to starting device 51 and deenergize PTCR 45.
Of course, this deenergization of PTCR 45 not only alleviates any voltage drop across it but also permits it to cool in anitcipation of a subsequent starting operation of prime mover 11.
With reference again in general to the drawings and recapitulating at least in part with respect to the fore~
going, circuit means 33 in one fo~m of the invent.ion is adapted for connection across power source Ll~ L2 so as to control the energization of prime mover 11 having main winding means 27 .
and auxiliary winding means 29 adapted for excitation in parallel circuit relation with each other (.FIGS, 1~8). Means, such.~s starting device 51 including PTCR 45, is coupled in serieg ctrcu~t relation with auxiliary winding means 29 for inhibiting the excitation thereof generally at a preselected : ' .' . '.' ~~~ ;, . 03~AC-SOL7 7~,~
t speed prime mover 11~ an~ me~n~, suc~ a~S rela~ device 41, is r~
operahle generally ~n resporr~e to a pregelected condition ~
associated with the exaltation o~ main winding means 27 ~:
for disassociatiny the inhibiting means or start~ng device S from circuit relation with power source Ll, L2 (FIGS. 1-8).
Referrinsg now to FIG. 2, prime mover 13 is shown functioning in circuit means 33 and operated by the above described method generally in the same manner as the previously described prime mover 11 with the exceptions discussed hereinafter, and it is believed that prime mover 13 functioning in combination with ~he components of circuit means 33 attains indigenous objects and advantageous features as well as meeting at least some of those set out hereinbefore.
Prime mover 13 is a capacitor start induction run type, and a start capacitor 63 is illustrated as being serially connected in circuit relation between auxiliary winding means 29 and starting device 4~. If desired, start capacitor 63 may be an integral or permanent part of winding circuit 53 of prime mover 13, or alternatively the starting capacitor may be "hung" or electrically connected between prime mover terminal 57 and starting device 51 by the use of a plurality of leads having quick connect fittings, as previously mentioned.
Start capacitor 63 is utilized in prime mover 13 to improve the starting torque thereof, as is known in the art, and since . 25 circuit branch 37 is opened by relay device 41 generally as :.
'.
-21- '~
' 03-AC~5010 ' ;~
'7~ 3 "t';~
~', prime mover 13 attains its pre~elected 3,peed generally at the '"', end of its~startlng mode or period, as previously discussed, ~,, the start capacitor will digcharge through auxlliary winding means 2~. Thus, it may be noted that the si~e of start capacitor 63 may be opt,imized with respect to prime mover 13 so as to provide maximum starting torque values therefor.
In FIG. 3, prime mover 15 is shown functioning in circuit means 33 and operated by the above described method generally in the same manner as the previously described prime mover 11 with the exceptions discussed below, and it is ; believed that prime mover 15 functioning in combination with components of circuit means 33 attains indigenous objects and advantageous features as well as meeting at least some of those set out hereinbefore. ', Prime mover l5 is a resistance start capacitor run type, and a run capacitor 65 i5 connected in winding circuit 53 '' of the prime mover between terminals 51, 59 thereof. Of ~ course, run capacitor 65 is provided to improve the efficiency ; of prime mouer 15 by effecting the utilization of auxiliary winding means 27 during the running mode operation of the prime mover, as isknown in the art, and since circuit branch 37 is opened by relay device 41 generally as prime mover 15 attains its preselected speed generally at the end of its starting mode or period, as previously discussed, the run -, 25 capacitor,will discharge through winding circuit 53 o the prime mover. Thus~ it may be noted that the size of run :
capacitor 65 may be optimized with respect to prime mover 15 ';-, so as to provide maximum running efficiency therefor.
In FIG. 4, prime mover 17 is shown functioning in circuit means 33 and operating in accordance with the above 03-~C-501 ~L~3L7'58~3 described method generally in the ~ame manner as previously '' described pr~me mover 11 wlth the exaeptions d~5cussed below, and it is belleved that prime maver ~ fanationing in com~in~ '' ation with components o circuit meang 33 atta~ns indigenous ~, objects and advantayeous features as well as meetiny at least - some o~ those set out hereinbefore.
Prime mover 17 is a capacitor start capacitor run type. Run capacitor 65 is connected between prime mover ;
terminals 57, 59 t and start capacitor 63 is serially connected in circuit relation between starting device 51 and prime mover terminal 57. As previously mentioned, start capacit:or 63 may either be an integral part or component of prime mover 17 or may be "hung" thereon by suitable electrical leads having ;
qui~k connect fittings. As well known in the art, run capac~
itor 65 is utilized to improve running efficiency of prime mover 17 by effecting the utilization of auxiliary winding ,~
means 27 during the running mode of the prime mo~ér, and start capacitor 63 provides increased starting torque during the starting mode of t~e prime mover. Of course, circuit branch 37 is opened by relay device 41 generally as prime mover 17 attains its preselected speed generally at the end of its starting mode or period, as previously discussed and continued excitation of main winding means 27 along with ~ auxiliary winding means 29 through capacitor 65 energizes ^ 25 the prime mover in its running mode. In this particular prime mover construc~ion, start capacitor 63 will either discharge internally or through PTCR 45 when relay contact means 43 axe closed in branch circuit 37, and run capacitor 65 will discharge through wind~ng circuit 53 of prime mover 17. Thus~ it may be noted that tne s~zes o~ capacitors 63, 65 may be optimized with -23- :
~,
3~ 7~8~ ~
"
respect to prime mover 17 not only to provide maximum starting torque but also maximum running ef~iciency.
Referring now to FIGS. 5-8~ prime movers 11~17 are shown func~ioning in another c~ rculk or clrcuit means 67 and js operating in accordance with the above described method with ,~
the exceptions discussed below, and it is believed that prime movers 11-17 functioning in combination with components of , circuit means 67 attain indigenous objscts and advantageous features as well as meeting at least some of those set out hereinbef~re, respectively.
Circuit means 67 in one form of the invention is provided for controlling current flow to the above discussed prime movers 11-17 and operates generally in the same manner as the previously described clrcuit means 33; however, in circuit means 67 a combination starter-protector device 69 is employed including an overload protector or current carrying thermal responsive switch means 71 and a PTCR 73 disposed generally closely adjacent each other in heat transfer relation. Combination starter-protector device 69 may be a model 3ARR32 available from General Electric Company, Morrison, Illinois. Overload protector 71 is generally the same as the previously discussed overload protector 60 and is serially ' interconnectsd between power terminal Ll and circuit branches 35, 37 of circuit means 67. PTCR 73 is generally the same as the previously discussed PTCR 45 and is serially connected in circuit branch 37 with contact means 43 of relay device 41.
In the event of the occurrence of a current overload condition in circuit means 67 which may have a deleterious 03-~C-5~10 t,~8~
affect on prime movers 11-17, overload prokector 71 senses such overload conditions and opens the circuit means across line terminal Ll, L2 which, of course, effects -the de-energization of the components of -the circuit means. After a preselected period o time, overload protector 71 cools and replaces circuit means 67 across line terminals Ll, L2 which, of course, reenergizes the components of the circuit means; however, if the overload condition still exists in the circult means, then the overload protector again senses the overload condition and acts to again open the circuit means across the line terminals. So long as the overload condition exists, overload protector 71 will be thermally cycled to open and close circuit means 67, but the length of time the thermal protector cyclically closes the circuit means is predeterminately of a generally short duration wherein the components of the circuit means are not deIeteriously affected. Of course, PTCR 73 is energized during the cyclical closure of the circuit means 67 by overload protector 71 under the aforementioned overl~ad conditions, and the heat generated by the PTCR
upon its energization is transferred to the thermal prot-ector so as to increase the "off" time thereof, i.e. increase the time the thermal protector cycles the circuit means open across line terminals Ll, L2 during the period of time the overload condition exists. If a more detailed discussion of the operation and/or construction of com-bination starter-protector device 69 is desired, reference may be had to the Lee O. Woods et al. U,S. Patent No.
"
respect to prime mover 17 not only to provide maximum starting torque but also maximum running ef~iciency.
Referring now to FIGS. 5-8~ prime movers 11~17 are shown func~ioning in another c~ rculk or clrcuit means 67 and js operating in accordance with the above described method with ,~
the exceptions discussed below, and it is believed that prime movers 11-17 functioning in combination with components of , circuit means 67 attain indigenous objscts and advantageous features as well as meeting at least some of those set out hereinbef~re, respectively.
Circuit means 67 in one form of the invention is provided for controlling current flow to the above discussed prime movers 11-17 and operates generally in the same manner as the previously described clrcuit means 33; however, in circuit means 67 a combination starter-protector device 69 is employed including an overload protector or current carrying thermal responsive switch means 71 and a PTCR 73 disposed generally closely adjacent each other in heat transfer relation. Combination starter-protector device 69 may be a model 3ARR32 available from General Electric Company, Morrison, Illinois. Overload protector 71 is generally the same as the previously discussed overload protector 60 and is serially ' interconnectsd between power terminal Ll and circuit branches 35, 37 of circuit means 67. PTCR 73 is generally the same as the previously discussed PTCR 45 and is serially connected in circuit branch 37 with contact means 43 of relay device 41.
In the event of the occurrence of a current overload condition in circuit means 67 which may have a deleterious 03-~C-5~10 t,~8~
affect on prime movers 11-17, overload prokector 71 senses such overload conditions and opens the circuit means across line terminal Ll, L2 which, of course, effects -the de-energization of the components of -the circuit means. After a preselected period o time, overload protector 71 cools and replaces circuit means 67 across line terminals Ll, L2 which, of course, reenergizes the components of the circuit means; however, if the overload condition still exists in the circult means, then the overload protector again senses the overload condition and acts to again open the circuit means across the line terminals. So long as the overload condition exists, overload protector 71 will be thermally cycled to open and close circuit means 67, but the length of time the thermal protector cyclically closes the circuit means is predeterminately of a generally short duration wherein the components of the circuit means are not deIeteriously affected. Of course, PTCR 73 is energized during the cyclical closure of the circuit means 67 by overload protector 71 under the aforementioned overl~ad conditions, and the heat generated by the PTCR
upon its energization is transferred to the thermal prot-ector so as to increase the "off" time thereof, i.e. increase the time the thermal protector cycles the circuit means open across line terminals Ll, L2 during the period of time the overload condition exists. If a more detailed discussion of the operation and/or construction of com-bination starter-protector device 69 is desired, reference may be had to the Lee O. Woods et al. U,S. Patent No.
4,042,86Q dated August 16, 1977 and the Donald H. Stoll 3Q Canadian application Serial No. 234,115 dated August 21, 1975.
From the foregoing, it is now apparent that prime '5~B
movers 11, 13, 15, 17, a method of opera-ting such prime movers, a method of interrup~iny means for inhibiting current flow therethrough, and circuit means 33, 67 are presented meeting the objects ancl adva:ntayeous :Eeatures set out herein-before, as well as o-thers. ~t is contemplated that chanyes as to the precise arrangement, shapes, details and connections of the components illustrated herein by way of disclosure, as well as the precise order of the steps of the illustrated methods, may be made by those having ordinary skill in the art without departing from the spirit of the invention or the scope thereof as set out in the claims which follow.
! ~
From the foregoing, it is now apparent that prime '5~B
movers 11, 13, 15, 17, a method of opera-ting such prime movers, a method of interrup~iny means for inhibiting current flow therethrough, and circuit means 33, 67 are presented meeting the objects ancl adva:ntayeous :Eeatures set out herein-before, as well as o-thers. ~t is contemplated that chanyes as to the precise arrangement, shapes, details and connections of the components illustrated herein by way of disclosure, as well as the precise order of the steps of the illustrated methods, may be made by those having ordinary skill in the art without departing from the spirit of the invention or the scope thereof as set out in the claims which follow.
! ~
Claims (9)
1. A prime mover adapted for energization generally to a preselected speed therefor across a power source, the prime mover comprising at least a pair of winding means for excitation to effect the energization of the prime mover generally to the preselected speed when it is energized across the power source, a PTCR associated with one of said winding means of said at least pair thereof and energized with the prime mover across the power source so as to inhibit the excitation of said one winding means generally as the prime mover attains its preselected speed, and means operable generally in response to a preselected condition associated with the excitation of the other of said winding means of said at least pair thereof and indicative of the occurrence of the preselected speed of the prime mover for effecting the deenergization of said PTCR
generally as the prime mover attains its preselected speed.
generally as the prime mover attains its preselected speed.
2. A prime mover as set forth in claim 1 wherein said deenergization effecting means comprises contact means in circuit relation with said PTCR for movement between an open position and a closed position, said contact means being disposed in the open position to effect the deenergization of said PTCR.
3. A prime mover as set forth in claim 1 wherein said deenergization effecting means comprises means associated with said other winding means for generally conjoint excitation therewith and operable in response to the preselected condition indicative of the occurrence of the preselected speed of the prime mover to initiate the operation of said deenergization effecting means causing the deenergization of said PTCR.
4. A prime mover as set forth in claim 1 wherein said deenergization effecting means comprises a relay device having contact means associated with said PTCR for movement between open and closed positions, and coil means associated with said other winding means for effecting the movement of said contact means between the open and closed positions thereof, said coil means being operable generally in response to the preselected condition indicative of the occurrence of the preselected speed of the prime mover to effect the movement of said contact means to the open position thereof and thereby cause the deenergization of said PTCR.
5. A prime mover as set forth in claim 1 further comprising a device for protecting said at least winding means pair in the event of the occurrence of a current overload condition including switch means for effecting open circuit relation between the power source and the prime mover upon the occurrence of the current overload condition, said PTCR being disposed in said device in spaced relation with said switch means so as to transfer heat thereto when said PTCR is energized.
6. In combination, a prime mover adapted to energization in both a starting mode and a subsequent running mode across a power source and a PTCR energized with the prime mover so as to predeterminately terminate the starting mode energization of the prime mover; the improvement comprising means energized with the prime mover and operable generally in response to a preselected condition indicative of the occurrence of the running mode energization of the prime mover for interrupting the energization of the PTCR generally as the prime mover attains its running mode energization.
7. The prime mover as set forth in claim 6 wherein said interrupting means comprises a relay device.
8. The prime mover as set forth in claim 6 wherein the preselected condition is a drop in the current draw of the prime mover generally as it attains its running mode energization.
9. The prime mover as set forth in claim 6 wherein the improvement further comprises thermal responsive switch means operable generally for interrupting the energization of
9. The prime mover as set forth in claim 6 wherein the improvement further comprises thermal responsive switch means operable generally for interrupting the energization of
Claim 9 continued:
of the prime mover across the power source in the event of the occurrence of a current overload condition, the PTCR being disposed adjacent said switch means so as to transfer heat thereto when the PTCR is energized.
of the prime mover across the power source in the event of the occurrence of a current overload condition, the PTCR being disposed adjacent said switch means so as to transfer heat thereto when the PTCR is energized.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000312801A CA1117588A (en) | 1978-10-05 | 1978-10-05 | Prime mover, method of operating such and circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000312801A CA1117588A (en) | 1978-10-05 | 1978-10-05 | Prime mover, method of operating such and circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1117588A true CA1117588A (en) | 1982-02-02 |
Family
ID=4112545
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000312801A Expired CA1117588A (en) | 1978-10-05 | 1978-10-05 | Prime mover, method of operating such and circuit |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1117588A (en) |
-
1978
- 1978-10-05 CA CA000312801A patent/CA1117588A/en not_active Expired
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