US1047557A

US1047557A - Electrical low-speed cut-out.

Info

Publication number: US1047557A
Application number: US66197811A
Authority: US
Inventors: Michael F Owens
Original assignee: AUTOMATIC REFRIGERATING Co
Current assignee: AUTOMATIC REFRIGERATING Co
Priority date: 1911-11-23
Filing date: 1911-11-23
Publication date: 1912-12-17
Anticipated expiration: 1929-12-17

Description

M. I. OWENS.

ELECTRICAL LOW SPEED GUT'OUT. APPLICATION FILED H0123, 1911.

Patented Dec. 17, 1912 5 me wto'a sgkdattznuf Z 2 Q unrrnn STATES PATENT OFFICE.

'HICHAEL-I. owns, or m'rro'nn, connnc'rrcn'r, ASSIGNOR TO mmmm 1m- FBIGEBATING OOIPANY, OF HARTFORD, CONNECTICUT, A. CORPORATION OF KEW Patented Dec. 17, 1912'.

ELECTRICAL LOW-SPEED CUT-OUT.

1,047,557. Specification of Iietters Patent.

Application filed November 28,1911. Serial No. 661,978.

To all whom it my concern:

Be it known that I,'MICHAEL F. Owens, a citizen of the United States, and resident of Hartford, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Electri-.

cal Low-Speed Cut-Outs, of which the following is a full and clear specification, illustratedin the accompanying drawings, the particular novel features of the invention being more fully pointed out in the annexed claims.

My invention relates in general to cut out mechanism which comes into operation when the motor for driving mach1nery of any kind fails to start within a predetermined time.

In particular my invention relates to a mechanism which enables me to out out the operation of the motor even if the latter should complete. its starting within the predetermined time but, through some cause,

.the driven mechanism should not readily start with the motor. As anexample in refrigerating apparatus the compressor is frequently driven by an electromotor by means of a belt. Now, aside from the danger that the motor itself should not complete its startin period within a predetermined time throug some cause in the electromotor itself, so that it should be immediately cut oil from the current supply, there is.also the danger that, while the motor may complete its startin period within the predetermined time, the elt which drives the compressor may slip so that within this time the. com-- pressor has not attained 'itsnormal speed. This puts an undue strain on the driving belt and therefore also in this case the motorshould be out off immediatelyfrom the current supply. The apparatus illustrated, is particularly designed to cut the motor off when the driven machinery fails to start, notwithstanding the normal starting of the motor, and therefore-the apparatus is connected to the power transmission system and only indirectly to the motor, but it is obvious that the'apparatus without changing its arrangement in its essential features, may be also employed directly at the motor and directly. connected with it so that it supervises the speed of the motor alone.

p In the accompanyin drawings, I have shown substantially diagrammatically my novel mechanism in connection'with a wiring system for an electromotor particularly adapted to respond to the actions of the thermostat of a refrigerating system, and

it is assumed thereby that the cut out control mechanism is belt connected to the compressor.

. The construction of the cut out mechanism which is indicated at 1 in the drawings is as follows: On base plate 2 are mounted.

two u rights 3 and 4: in and between which a shat 5 is journal'ed which carries belt pulley 6 by means of which shaft 5 may be driven from the compressor D, the speed of which the device is to supervise. Connected with pulley 6 is a governor 7 so that the col-- lar 8 of the governor may slide toward and away from pulley 6, according to whether the pulley runs fast or slow. The governor springs 9 normal1y tend to move a collar 8 away from pulley 6. Upright 4; is longer than upright 3 and carries a solenoid coil 10, the core 11 of which carries at its upper end a piston 12 disposed in a dash pot cylinder 13 with a valve 14 at its upper end. The dash pot cylinder 13 is open at its lower end. The armature or core 11 has also a downward extension 15. which is guided in a bracket 16, integral with upright 4 the lower end of this extension carrying a roller 17 which, when solenoid 10 is deenergized so that the armature 11 is in its lowermost position as shown, is in the path of collar 8 of the governor and prevents this collar from further sliding to the left under the tension of springs 9. However, as soon as pulley 6 has attained the proper speed collar 17. When the solenoid 10 is energized in the manner which will be described pres ently, the armature 11 is drawn'in against the resistance of the dash pot so that only after a predetermined time, controlled by the setting of valve 14, armature 12 will be completely drawn in so that roller '17 is removed hereby from the path of collar 8',

and thus the latter is enabled to further travel to the left under the influence of springs 9 should the pulley 6 not rotate fast enough'to cause the'governor balls 18 to draw the collar-to the ri ht. Adjacent to collar 8, but slightl fart er to the left of energizing of solenoid 10, roller 17 should be moved out of the path of collar 8 and through lack of speed of the governor this,

collar should be thus permitted to further slide to the left beyond the margin normally set by roller 17, it will strike the upri ht shank of bell crank 19 and rock it there y, interrupting the contact between contact elements 20 and 21 which, as shown, are normally closed.

The apparatus which I have just described may be employed for instance in a circuit arrangement for controlling the cutting in and out of a motor which may drive a compressor for refrigerating systems as follows: In the drawings M indicates the motor which drives the compressor D as shown. From pulley 41, mounted on the compressor shaft 40, a small belt runs over pulley 6 of the cut out device. The mains supplying current to the" motor are indicated at a, b, 0 and (1, motor M being illustrated as a two-phase motor. 25 is a main switch which is controlled by solenoid 26. The armature 27 of the solenoid which is Shown in denergized position is connected at its upper end with switch 25 which is shown open and at its lower end it has attached to ,it two

contact bars

28 and 29 which coiiperates with arm T when the-motor should stop. The elements are all shown the cut out control, contact spring 22, linein resting position. If now the thermostat arm calls for starting of the motor and thus moves over to contact H the following circuit is closed: from main 6 over contact e of switch 25, line 31, across contact bar 29 which is then closed, line 32, contactH, thermostat arm T, line 33, contact arm 20 of 34-, solenoid coil 26, resistance y main a. The solenoid 26 being energized thereby closes its switch 25 so that motor M receives current through the mains a, b, .0, and d.

The closing of switch 25 also closes a shunt circuit between mains a and b which branches ofi from main a by way of line 24, solenoid coil 10 of the governor cut out, line 35, and

back to switch 25 and main 6. The closing of the motor circuit effects the starting of thermotor and it is assumed that normally the driven compressor will start its operation with the motor so that gradually. pulley 6 is driven faster and faster, whereby collar ,8 of the governor is removed from the roller 17. The simultaneous energizing of sole noid 10, previously mentioned, also starts the upward movement of its armature 11 against the resistance of the dash pot, whereby gradually roller 17 is removed from the path of collar 8. The retarding action of'the dash pot thus prevents an immediate removal of roller 17 at a time when, owing to the inertia of the system, the pulleyfi cannot possibly have attained suflicient speed to move the collar 8 to the right against the tension of springs 9. The upward movement of armature 27 of switch solenoid 26 also removes contact bar 29 from its contacts and presses contact bar 28 upon its contacts so that the current which runs throu h lines 33 and 34 runs around thermostat 32 l yway of line 31, resistance :19, bar 28, line 36 to line 33. This prevents current permanently flowing through the thermostat. If now the 'driven machinery should have failed to at tain its normal speed, after the dash pot has removed roller 17 from the path ofcollar 8,

within predetermined time, for instance on account of slipping or breaking of the belt, the slowin down of pulley 6 permits collar -8 under t e action of springs 9, to freely slide to the left where it will strike bell crank 19.and by rocking it interrupt contacts 20, 21. This opens the circuit through the switch solenoid 26 so that the latter w1ll drop its armature 27 and open the main switch 25 and stop the motor. If normal running conditions exist, that is when the driven machine has attained its speed and collar 8 has been drawn to the right, and now thethermostat arm T moves to the left onto its contact 0, whereby the solenoid coil 26 is short-circuited by the short circuit main a,

resistance y, line 37, contact C, arm T, line 36, bar 28, resistance w, line 31, main 5, in

gradually move back to the left long after roller 17 has moved into its path and thus when the overnor comes to a standstill, colspeed responsive lar 8 will beprevented from further moving to the left and striking bell crank 19 which, by gravity, or other suitable means, alwa s tends to close contacts 20 and 21. It is o "ions from the description of the apparatus that it will also stop the motor when in normal running condition if the belt should suddenly slip off or break through some cause, because then the motor current bein still turned on, solenoid 10 is fully energize and has lifted roller 17, while then the governor collar 8 is free to move to the left and strike the bell' crank 19 when the governor slides down. I

What I claim is:

1. In a power transmission system hav mg a motor and machinery driven thereby, a cut out mechanism comprising an element responsive to speed variation and operated by said transmission system, an element controlling the sto ping of the motor, said e ement adapted to operate-said stopping element when the 5 ed of the system falls below the desired limit, and means removably disposed between said speed responsive element and said stoppin element for preventing the actuation of sai stopping element during a predetermined time to permit starting and accelerating of said system, and means for removing said interposed means within a predetermined time after the motor has started.

2.'In a power transmission system having a motor and machinery driven thereby, a cut out mechanism comprising an element responsive to speed variation and operated by said transmission system, and an element controlling the stopping of the motor, said speed responsive element adapted to operate said stopping element when thespeed of the system falls below the desired limit, and dash-pot-controlled means removably disposed between said speed responsive element and said stopping element for preventing the actuation of said stopping element during a predetermined time to permit starting and accelerating of said systemand means for removing said dash pot cont-rolled means after the motor has started.

3. In a power transmission system-having a motor and machinery driven thereby, a cut out mechanism comprising an element responsive to speed variation. and operated by said transmission system, and an element cont-rolling the stopping of the motor, said speed responsive element adapted to operate said stopping element when the speed of the system falls below the desired limit, and dash-pgt-controlled means nor-' mally interposed tween said two elements for preventing .the actuation of said stop ping el'ement, said means adapted to move away from its normal position within 'a pre determined time after the starting of the motor, to permit'actuation of said stopping element w en the speed of the system falls below the desired limit and means-for actuating said dash pot controlled means when the motor starts.

j 4. In a power transmission system having a motor and machinery driven thereby, a

cut out mechanism comprising a governor operated by said transmission system, and a motor cut out, said governor adapted to operate said out out below the desired speed limit of the system, and a dash-pot-controlled element disposed'betwe'e'n said governor and said out out to prevent o eration of the latter before the starting an durin' the acceleration period of the system, sai element having means actuated at the starting of the motor and adapted to move said element from its normal position against the resistance of the dash potwith' the starting of the motor.

5. In a power transmission system having an electromotor and mechanism driven thereby, a cut out'mechanism comprising a governor operated by said transmission sys-- tem, and an electric motor cut out,- said governor adapted to operate said out out below the desired speed limit of the'system, and a solenoid electrically connected to the motor to receive current simultaneously with the motor and. havingone end of'its armature in deenergized position located between said governor and said out out to prevent actuation of the latter before and. during the starting period of the motor, and having its other end connected with a dash pot, said armature starting to move away from its normal position against the resistance of the dash pot'when the solenoid is energized and the motor starts, and permitting said gov} ernor after a predetermined time controlled by said dash pot, to operate said out out if. t e speed of the motor should fall below the;

desired limit.

6. In a power transmission system having an electromotor and mechanism driven thereby, a cutout mechanism comprising a governor operated by said transmission system, and an electric motor cutout consisting of governor to permit said governor to open said switch below the desired speed limit of a switch having an actuating arm in the-path of a sliding collar attached to said the system and a solenoid electrically connected to the motor to receive current s1- multaneou sly with the motor and having one end of its armaturein deenergized position located in the path of said collar to prevent'its engagement with said actuating arm before and during the starting period of the with a dash pot, said armature starting to out out the motor if the I move away from said collar agalnst the resistance of the dash pot when the solenoid said actuating arm to' open the switch and eed of the system should fall below the deslred limit.

' MICHAEL F. OWENS.

Witnesses:

.I. K. HAMILTON, Jr., A. T. MARSHALL.

motor and having its other end con ne cted is energized and the motor starts and erlnitting said collar after a predetermmed time controlled by said dash pot to engage