US1834217A - Switch - Google Patents

Description

Dec. l, 1931. c. E. L.. LIPMAN 1,834,217

SWITCH Filed oet, fr. 1927 l 719 J8 J6 Z6 l (7 l! Iii Q 5 "w igi ,/9

Patented Dec. 1, 1931 UNITED STATES` PATENT. OFFICE CARL E. L. LIPMAN, OF BELOIT, WISCONSIN, vASSIGNOB T LIPMAN PATENTS CORPORA- TION, 0F CHICAGO, ILLINOIS, A CORPORATION OF DELAWARE swrrcn Application led October 7, 1927. Serial No. 224,570.

This invention relates to induction motors of the split phase type and more particularly to a switch for cutting out the auxlliary starting winding of such motors after the 6 motor as started.

In the past it has been vcustomary to cut out the auxiliary starting winding of induction motors by means of a centrifugal switch carried by the armature which was thrown open when the armature had gathered speed.

The use of such a switch often involves many diiiiculties particularly when the motor is used in the vicinity of gases or the like which are apt to be exploded by the spark from the switch and/or when the motor is sealed so that the switch parts are not accessible except by breaking the seal. Furthermore the physical construction of the motor in some instances make it difficult to mount the switch in the vicinity of the armature.

The primary object of this invention is to provide a switch which overcomes the above diculties and is adapted to be mounted outside the motor.

Another object of this invention is to provide a switch for the above purpose which'A will not cause a, spark and may thus be used where the motor is either sealed or mounted in the vicinity of explosive gases.

A further object is to provide a fan operated switch which is particularly suitable for use in connection with induction motors for automatically cutting out the auxiliary starting winding.

Other and further objects of this invention will be apparent as the same becomes better understood from an examination of 4o the specification" and claims in connection with the accompanying drawings, wherein:

Fig. 1 represents a fragmentary front elevation of av refrigerator cabinet with a portion cut away to illustrate a refrigerating unit embodying this invention,

Fig. 2 is a horizontal sectional View of the cabinet showing a plan of the unit,

Fi 3 is a diagrammatic sketch illustrating t e connections to the various windings.l ofthe induction motor, and

Fig. 4 is a diagrammatic sketch illustratinga modified form of the invention.

eferring to the drawings more particularly, numeral 5 indicates a refrigerator cabinet which may be of the type illustrated and described in my copending application Serial No. 92,704, filed March 6, 1926. The cabinet 5 is provided with a removable refrigeration unit including the evaporator element 6 carried by and attached to the underside of a removable wall 7, the high pressure side ofthe unit being'carried b and attached to the top of said wall. T e removable wall 7 forms the top yof the refrigeration storage chamber of the cabinet and acts to insulate the evaporating element 6 from the high pressure side of the unit.

The high pressure side of the unit includes a hermetically sealed motor compressor unit 8 and a condenser 9, both positively air cooled by a fan 11. driven by the motor 12.

The motor compressor 8 includes a single phase induction motor adapted to be driven from an electric light circuit and in order to facilitate starting the motor it is provided with a splitphase or auxiliary starting winding 13 in a dition to the usual single phase induction winding 14, each of said windin being connected in parallel and a'switch 5 being interposed for connecting and disconnecting the starting winding.

In the past it has been customary for the switch which was used to disconnect the starting winding after the motor has gathered speed to be in the form of a centrifugal switch carried by the armature. Such a switch would not be practical in this case because of the fact that the motor compressor is sealed. The switch parts are subject to wear and were the switch on the armature the casing of the 00 motor would have to be opened to inspect, renew or repair these parts. Furthermore it would be diiticult, due to the physical construction, to carry such a switch on the armature and even if this could be done the spark might, if some forms of gases were in the system, result in an explosion. Accordingly, the switch is mounted outside of the motor compressor as illustrated in Figs. 1 and 2 and 3911s in the 'form of a mercury contact switch including an enclosed tube 16 into which the Contact points 17 and 18 project in position to be submerged in and electrically connected by a predetermined amount of mercury coni ined 'the tube which is supported on a pivot i9 at the upper end of a bracket supf" A vane 22 depending from the pivot idly carin-acted. to the tube 16 and is the path of the cooling air cirhe ian 11 whereby it may be actuated by e dow of said air to tilt the tube 16 and open the switch after the fan has com- 'to operate. The fan motor 12 is in cir cuit with the motor compressor and operates concurrently therewith so that by the time the flow of air caused by the fan is sufiicient to open the switch and cut out the starting winding 13 the motor will have been started. So long as the fan continues to operate the switchwill remain open but as soon as it stops together with the motor compressor the vane 22 will swing downwardly and close the switch again. As shown in Fig. 4 this invention may be utilized in connection with any motor embodying an auxiliary starting winding which is desired to be cut out when the motor has been started. In this figure numeral 23 desi gnates a split phase motor provided with a fan 24 on its own armature shaft. A switch 25 similar to the switch 15 is rovided in the auxiliary starting circuit an is adapted to be opened and kept open by the flow of air caused by the fan 24. As soon as the motor 23 stops the flow of air will stop and the switch 25 will automatically cut the starting winding in again so that it will be in circuit 'when the motor circuit is closed to restart the motor. The switch may be positioned on either the discharge or suction side of the fan. The circuit shown in the cabinet in Figs. 1 and 2 may be connected to a source of current supply as by means of the plug 26. The circuit for controlling both the compressor motor and fan motor is established through a thermostatic switch 27 which is operated by means of the thermostatic element 28 connected therewith and located inv the evaporator. Whenever the temperature of the ther- 00 mostatic element 28 becomes high enough, the

thermostatic switch 27 will cause the compressor and fan motors to be started. Both motors will be stopped by the switch 27 when a predetermined lower temperature has been attained at the position of the element 28.

It will be apparent that while this form of switch has been illustrated in combination with a refrigeration system it may have many other uses and many changes may be made without departing from the principles of this invention and I therefore do not wish to be limited to the details shown and described.

I claim:

l. In a refrigerati-ng s stem the combination of a compressor an a motor for driving the saine incloscd together within a scaled housing, the motor being' provided with a normal running winding and an auxiliary starting winding, a fluid contact switch in a sealed tiltable casing for opening 'and closing the circuit to said starting winding, a second electric motor and a fan driven thereby positioned to blow air onto the exterior of said housing for cooling the same, the circuit controllingvthe operation of the ian motor being in parallel with the circuit controlling the starting and stopping of the compressor motor, and a vane constructed to be moved by the air propelled by said fan to tilt the contact -switch to open thc circuit of the starting winding and upon the stopping of the fan to restore the contact switch to closed contact position.

2. In a refrigerating system the combination of a compressor and a motor for drivin the same inclosed together within a sealed housing, the motor being provided with a normal running winding and an auxiliary starting winding, a Huid contact switch in a sealed tiltable casing for opening and closing the circuit to said starting winding, a second electric motor and a fan driven thereby positioned to blow air onto the exterior of said housing for cooling the same, the circuit controlling the operation of the fan motor being in parallel with the circuit controlling the starting and stopping of the compressor motor, and a vane' positioned between the fan and the com ressor housinvP constructed to be moved by tiie air propelled by said fan to tilt the Contact switch to open the circuit of the starting winding and upon the stopping of the fan to restore the contact switch to closed contact position.

. 3. In a refrigerating system the combination of a com ressor and a motor` for drivin the same inc osed together within a sealed housing, the motor being provided with a normal running winding and an auxiliary starting winding, a fluid contact switch in a sealed tiltable casing for opening and closin the circuit to said startin windlng, a second electric motor and a fan driven thereby positioned to blow air onto the exterior of said housing for cooling the same, the circuit controlling the operation of the fan motor being in parallel with the circuit controlling the starting and stopping of the compressor motor, and a vane constructed to be moved by the air propelled by said .fan to tilt the contact switch toopen the circuit of the starting winding and upon the stopping of the fan to restore the contact switch to closed contact position the fan motor, fan and vane cooper- 5 ating to open the contact switch and the starting winding of the compressor motor when the compressor motor has attained normal running speed. p

In witness o f the foregoing Iax my sig- 10 nature. l

CARL E. L. LIPMAN.

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