US1589744A - Switch - Google Patents

Description

H. COHIC June 22 1926.

SWITCH 3 Sheets-Sheet l1 Filed Feb. 24, 1922 June 22 1926. 1,589,744

H. COHIC SWITCH Filed Feb. 24. 1922 3 Sheets-Sheet 2 ff ma@ fijar Patented June 22, 1926.

UNITED STATES HENRY COHIC, OF CLEVELAND, OHIO.

SWITCH.

Application led February 24, 1922. y Serial No. 538,958.

My invention relatesY to methods oi' and means ior shifting the connections ot' electric motors; andy is more especially related to alternating current motors of the polyphase type. It has forit's objecty to shift the connections between the field coils of such type to either series or multiple at will; and to do this without' endangering.: the l'it'e oi" the motor, even when the motor is run indefinitely in either arrangement, where the motor is so wound that it can runin parallel without overheating.

It is well understood that, with a rgiven Volta-ge, motors vof the speciedv typeA will use less current and generate less horsepower when running in series than when runnin'g'in paralleli The difficulty in the vpast has beenV that no arrangement was thought feasible' to connect the field coils in series for permanent running when connected' directly with the mains afteri start'- ing in parallel and no means for shifting' over by switch mechanism to the multiple connection, where the larger loadl wasessential', had yet beenl devised. The common manner of starting an A. C. motor of the polyphase type was to use a starting box having` a transformer byy which a reduced .voltage of thatr 'required for normal" running was obtained, and which precluded rliinning by such starter for longer thanl a very few minutes at a time, otherwise the safety oil` the starter and ot' the motor itself 7as endangered'. For this reason employees '35 were often directed to never run the motor by such starter longer than one minute at a time, 'after which a single cut-out switch must be Vthrown to cut out the starter.

For the above reasons, motors` that 40 generated l() Pi when running in parallel and. but?) H. P. when running by the starter connection were not used in the latter connection for' any appreciable interval, even though but a 5 H. P. load was to be carried, but the current essential for said l0 H. P. had to be used. it such a motor was to be used'at all. This resulted ot course in great waste ofi current.

To remedy these disadvantages, it is my purpose to dispensev with the starter boxes altogether and use a switch of my special design tor making the desired connections of fieldc'oils as' above explained.

It is a further object of my invention to make the shift 'above stated by a manual deu'bl'e throw switch from series arrange ments to parallel or vice versa; and to use a plurality oil blades for the purpose of making connection with one set of contacts immediately after disconnection with the other, thus avoiding a long interval between the two connections.

I `further propose to wind ymy motor of the three-phase type with an additional conductor `in parallel with certain of the lines usually found in motors of this type, and to make this line alternative by leading `it from# contacts which are not touched bv vthe switch as ordinarily used, but which wiilr be reached' by a further thrust of the svitch blade when a positively rovided obstacle, ordinarily `held in its pat 1, is released.

A further object is to provide a switch oi' the blade type which though ordinarily engaging trom 3-5 contacts will be so constructed that three, for example, will be contacted at first 'without closing the circuit, and a contact with the fourth or fifth clampA will be effected last of all. This is regarded as very important.

lVhile theL principle of my invention will be explained as embodied in a polyphase alternatingr current motor, it is to be eX- pressly understood that I am by' no means to be restricted to this typel of electric motors, but that it may be used on motors of the single-phase type as well, and on direct currentalso, alsoy for delta connec.- tion of the three-phase A. C. motor, though inY such cases with certain modifications to adapt it to the particular conditions present in the mechanism to be fitted. In each case, the number and connection oi the switch blades wvill reiluire appropriate adjustment to meet the individual case.

In. the drawings accompanying specification,

Figure l shows a four-Dole three-phase inducing winding of the Y type together with a blade switch for shifting to either series or parallel connection, or by further thrust to connect an additional wire in parallel when the mainrconductors are in series;

Figure 2 shows my invention applied to a four-pole two-phase motor;

Figure 3 shows a side view of the switch and-the slidable bar for preventing `the eX- treme position of the switch;

Figure 4 shows another side Viewy of the switch when-inthe lower position, and

thi s lll() lll Figure is aview of the slidable bar as shown in a transverse section on the line 5-5 of Fig. 3.

Referring now to Fig. 1, showing the Y- type of three-phase motor, the switch 34 is represented as having the blades 29 and 3() for engagement with the uppeiI contacts, and blades 36 for engagement with the lower contacts, the conductors to 15, and 2O to 26 are shown leading to the proper contacts for the switch blades, the contacts 10, 13 and 2O representing the additional lines for increasing the torque at starting, if such should be needed, and arranged in parallel but not effective, unless the upper blades of the switch are thrust in fully as shown in the broken and dotted line position in Fig. 3. The lines 2, 3 and 4 are shown as entering the switch through thel usual fuses 5. It will be seen from inspection of Figs. 3 and 4 that when the switch blades 29 and 30 are in engagement with the contacts 6 to 9, the blades 36 are out of contact with conductors below, and vice versa. This construction will be remembered when tracing the various lines in the diagram.

Assuming then, that the switch blades 29 and 30 are in the dotted line position of Fig. 3, the blades 29 will be in engagement with contacts 6 and 9, while blades 30 will contact 7 and 8. Current from line 2 will then pass from contact 9 tor 6 and thence to 16, and through line 11 to the motor field returning through line 23, thence through 7 and 8, line 12 and to the stop Where the Y connection is made. Current from line 3 leads through line 14 to the motor field returning through line 24, thence out through lines 15 to From line 4, current leads out through line 21, returning through line 25, thence out through 22 and to For this reason,` the 12 leads, otherwise required, will be reduced to 10, the three lines being joined at m as in this type of motor winding.. This connection will be seen to afford direct connection with the mains and will connect the coils of induction in series, as will be readily understood, as well as dispense with the starter which involves additional expense and requires insulation to prevent excessive heating of the elements.

-When the blades 36 are in engagement with the various contacts, referred to generally as 16 to 19, the series contactsthen being separated, the course of the current flow will be as follows: Line 2 divides at 16 and 17 and passes out through lines 11 and 12, the former leading to line 23 and the latter to Line 3 divides at 16 and 17 passing out through lines 14 and 15, the former returning to the switch by 24 and the latter leading to Line 4 leads through lines 21 and 22, the former to 25 4and the latter to Line 26 serves as a connector, when the switch is connected in parallel between the three lines uniting at a" and the three lines (23, 24 and 25) meeting at the blade 36 of the switch, as will be understood.

Thus it will be seen that all the coils are used, no change has been made in the winding of this type of motor in very general use, and the parallel connection has been made whereby approximately7 twice the horse power can be realized that was pos` sible from the series connection. The mere throw of this switch has made possible this selection of windings whereby when a lower load is to be carried, the coils of this standard wound motor are connected in series, but when the normal or larger load is to be carried, involving the larger use of current, the connection may be readily shifted to parallel, and this too by a double throw switch. The motor being constructed, to endure ruiming in parallel, neit-her position of this switch is injurious to the motor, and therefore the motor may be run in either position of the switch indefinitely.

It is usual to solder together the ends of the various coils of the motor so as to bring out the minimum number of leads. 1f coils that are to be run in series have their intermediate ends soldered together, and coils run in parallel have their like. ends soldered to common leads, normally I bring out both ends of each coil, and my switch malres the equivalent of these usually soldered connections. When the coils are to Vbe in series, as in the upper position of the switch, the intermediate ends are connected, as by contacts 7 and 3 and bar 30, and it is to be seen from Figs. 3 and 4, that this connection will be made before bar 29 reaches contact 9, so as to throw on the current. rlhis is evidently equivalent to soldering the ends of the coils before turning on the current. In the lower position of the connecting switch, like ends of coils to be run in parallel are connected by the switch. It is `to be. noted that in l either case, when the switch is opened, each coil of the motor is segregated, instead of being left connected as they must be when soldered together, and l deem this feature one of great importance in lessening sparking when the switch is opened.

lt will be found that sufiicient torque results from the series winding to start even with a load, but if itis desired for any reason to increase the torque at starting, an additional winding may be put on the motor field in parallel with certain ofthe lines for this particular purpose, and this additional winding will now be traced in this particular motor. Of course, it may be installed on the other polyphase motors of the alternating current variety ifit is desired.

lllhen used in this motor, the lines for this purpose, shown in Fig. 1, in section lines, will lead as follows: from 9 to 31,

. extreme position.

then to l() and finally to the -iunction at Y. Line 3 leads `from 9' to 32 to 13 and thence toi Y. leads from 9 to 33 and thence through 26 to Y, so that the additionall line in parallel can be used at starting when the switch arms and() are thrust in to the Y This latter is made possible by thel longitudinal shifting of the bar 27 which, as shown in Fig. 5, is provided, with high parts 37 and low parts 38, so that when the said bar is in the position shown at Fig. 5, the lines 10, 13 and 20 are not available. ill/Then however, the bar is shifted to bring the parts 38 in proper register, the said lines for extra torque will be connected, as explained.

Vfhilc the invention has been described as applied to three-phase motors thus far, it can be applied to all polyphase motors by proper arranging of the connections with the switch arms. It will now be described as applied to a two-phase motor of the alternating current type as shown in Fig. 2 of these drawings. Line C leads from 9 to 6, when the switch arms are in the upper or series position, thence through 17 and 10, then back through 12, 17, 7 and S, out through 11. then back through 13, 6, 9 and out at D. Line E leads through 9, 6, 17, 14, back through 19 then 7. 8, 18, 15, 20, 1S, 6, 9, and out at F. This results in a series connection. Vhen the switch is thrown to the lower position, the line C leads through 16. dividing at 17 and 18, the former leading through 10, 12, 17, 16 and out at D. The line from 11 leads through 13 and then out at D. Line E divides at 16 through 17 and 18 so that current passes through 14 and 15 and back through 19 and Q0 and this out at F, whereby the connections are made in parallel which is the normal ruiming position as it delivers the most power and therefore uses the most current from the mains.

It will. thus be seen that an alternating current motor need not be run in the parallel connection requiring the larger current for its use, unless so strong a current as may be Jfurnished by such parallel connection is desired, but that by my mechanism, the connection may be made in series by an easilvthrown switch so that a great economy in the current consun'ied may be gained without.

any loss in the life of the motor mechanism, and also saving the great expense of the starter unit. for which there will be no need when inv device is used.

lt further to be noted that by the provision of my unitary switch having a plurality of blades, all manually operable togethcr and arranged in at least two sets at an angle from each other, I am able to make various connections the character of which determined by the extent of thrust: that by thrusting the blades in one direction towarda cerrespending set o1" contacts, certaineo'ff said contacts: will first be connected by the blades which will unite the normally segregated coils, and that4 further thrust of' the blades will. then make a positive and accurate connection betweenv the connected coils andthe contacts which are directly connected with the mains. To more detinitely and concretely illustrate this arrangement, inf Fig. 1 of the drawings, the upper blades 29 and 30 of the switch mechanism first connect together contacts 6, 7 and S (See also Fig. 3), effecting a connection of the induced coils in series, and yet not making any connection whatever with the mains until. a further thrust is given the switch blades to reach the contacts 9, when the mains will thenl be connected with the coils in series. In the thrust of the blades in the opposite direction, 16, 17 and 18 are iirst connected, at the same time connecting the coils in parallel before connecting with the mains, after which a further thrust of the switch blades in that direction will connect the coils, so connected together, with the mains through the intermediacy of the contact 19. see Fig. 4 of the drawings. With this arrangement, too, the above-described use is unavoidable, for inward thrust of the blades must necessarily connect the various coils in either parallel or series, depending upon t-he direction of operation of the switch before making any connection with the mains, and opening the switch necessarily disconnects from the mains before changing the relative connections of the coils with each other. This is a feature which I regard of great importance. As further explained in our description, if it should be necessary to increase the torque at starting in series, the movement of the sliding bar may permit a further thrust of the switch blades which will result in connection with lower contacts that will throw in an additional line in parallel for this purpose. By locking the said bar in its normal position, however, such additional line will never be used, although the usual coils will be connected together before connecting with the mains, as above explained.

While my mechanism is illustrated and described as applied to an alternating current motor. it is by no means my intention to restrict its use to such motors, as the arrangement of the plural blade switches for use with direct current motors may he effet-ted. and l do not desire to limit myself other than as expressly stated in the following claims, interpreted in the spirit of my disclosure, and falling within the general scope of my invention.

Having fully described my invention, what l claim as new and desire to secure by Letters Patent of the United States, is:

A switch comprising a base, two sets of contacts mounted on Said base, the Conta-ets in each set being of three different lengths, a common hinge axis mounted on the base between the two sets of contacts, e plurality of arms mounted on. said axis in one plane, a plurnlit7 ol arms mounted on seid axis in another plane, the angle between said planes being more than 90 and lese than 180o, and e bei' having high and low levels thereon slicleble transversely of one set of Contacts,

the loWer of Said levels permit-ting engagement oi" the arms in one plane with contacts oi: two different lengths and the high levels permitting engagement With only contacts of the seme length, and the throw of the 15 switch permitting engagement of the arms with other contacts of the same length.

ln testin'ionf.7 whereof I hereunto aX my signature.

HENRY COHIC.

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