US1368326A - Relay - Google Patents

Description

R. E. DE CAMP.

RELAY.

APPLICATION mm OCT-8.1918.

1,368,326. Patented Feb. 15,1921.

Fig! 4 I5 24 I8 3 26 20 I7 4 I5 Fig. 2. WITNESSES: INVENTOR y 5 0 Camp. 5174M BY 7 ATTbRNEY comprise a UNITED STATES PATIENT" OFFICE.

BAY E. DE OAIP, OP WILKINSBUBG, PENNSYLVANIA, ASSIGNOB TO WESTINGHOUI ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

may.

Application filed 0mm 8, 191a Serial No. 257,349.

and electromagnetically actuated switches for the control of electric switches. In a more limited aspect, my invention relates to switches that are particularly adapted for unit-switch-control systems.

Control systems of the unit-switch type, largely used for governing electric motors,

plurality of independently operated individual switches .or contactors designed and connected to act successively to produce a gradual acceleration of the motors.

with which they are associated. In these systems, devices are ordinarily employed for delaying the action of the successive contactors in order to avoid injury to the motors One form of these by excessive currents.

of auxlllary devices comprises a pluralit switches or relays for governing the closing of the respective contactors. My invention comprises a rela which, though adapted for general use, fin s particular application in connection with such a system. In my a plication for current-limlt rela Serial 0. 241,259, filed June 21, 1918, have illustrated several forms of such a relay. The iplresent application is concerned with a modication.

I have illustrated my invention in connection'with a unit-switch accelerating system, in which the closing of each contactor is controlled by a coil, the circuit of which is closed by a relay. The time of closing of the relay is determined by the degree of energization of another 0011. Though this arrangement is by ,no means essential, I have illustrated the second coil as serving also the function of a blowout coil for the contactor. As in the above-mentioned application, the relay is biased toward closed position but is maintained open until the motor current falls to the roper value, the current itself, thus performing the work of releasing the rela at the proper time.

An 0 ject of my invention is to provide a novel relay for particular use in a u nitswitch accelerating system.

Another object of my invention is to rovide a relay, the controlling coil of w ich serves also as a blowout coil for one of the contactors.

Other objects of my invention will appear hereinafter.

In the drawings, Figure 1 is a partly elevatlonal and partly longitudinal sectional .v1ew of 'my relay, and F1 2 is a diagrammatic new of circuits an apparatus illustrating the use of this relay in a motor-accelerating system.

Referring to Fig. 1, the relay parts are supported, in any suitable manner, upon an msulating panel 1. A pair of magnetizable pole pieces 2, lined with insulating material 3, inclose'a coil 4 between them, which, when energized by current flowing through it, creates a magnetic field for attracting a plunger 5 and an armature 6. A compression spring 7 serves to return the plunger 5 to normal position upon the-deenergization of the coil 4. The force exerted by the spring 7 may be varied by a rod 8, the position of which, with respect to the plunger 5, may be adjusted, as by means of a screwthreaded connection 81. The plunger 5 is slidably mounted in a non-magnetizable tube 9, which, together with a magnetizable core 10, is located Within the opening of the coil 4. The rod 8 is slidably mounted in the core 10 and within an opening in the armature 6 and is rovided with an enlargement 11 for normal y engaging the armature 6, thereby to maintain this armature 6 in engagement with the core 10. The core 10 is adjustably secured to the tube 9 at 12, the tube 9 and the core 10 being respectively provided with flange members 13 and 18 for clamping the parts of the arc shield together. As the flange 13 is of non-magnetizable material, it serves also to prevent freezing of the plunger 5. The parts are so designed as normally to leave an adjustable air gap 14 between the core member 10 and the plunger 5 for the purpose of regulating the reluctance of the magentic circuit. The coil 4 is insulated from the core 10 at 15.

Although I have illustrated the plunger 5 as controlling a single armature 6, it

Specification of Letters Patent. Patented Feb. 15, 1921.

will be obvious that, as explained in my aforementioned application, the plunger 5 may be easily so designed as to control a plurality of armatures 6, each controlling a relay, as hereinafter described.

The armature 6 is pivotally secured at 16 to a supporting member 17 mounted upon the panel 1. A. spring 18 is coiled about a rod 19, which is rigidly secured to the panel 1, and which passes through an opening in an arm 20 of the armature 6, this armature 6 being preferably, as illustrated, of bell-crank shape. The. tension of the spring 18 may be so adjusted, as by means of nuts 31, as to exert a force weaker than that of the spring 7. The arm 20 carries a movable contact member 24 for coiip'erating with a stationary contact member 26 which is mounted upon the panel 1. The contact members 24 and 26 constitute a relay. Obviously, the contact member 24 may be, supported by the main portion of the armature 6 and, again, as illustrated in my above-mentioned application, the main portion of the armature 6 and the arm 20 may both serve to support contact members.

The coil 4, which may be a-series or a shunt coil, is adapted to be energized upon the closing of a contactor 45 and to serve as a blowout coil for this contact member.

The operation is a follows: Upon the closing of the contactor 45, (Fig. 2), current flows through the coil 4, whereupon a magnetic field is created which causes the plunger 5 to be drawn into the opening in the coil 4 toward the core 10. The rod 8 is thereby forced outwardly, the engagement between the part 11 and the armature, 6 being thereupon released. If the current is above a previously selected safe value, the magnetic field will overcome the force'of the spring 18, and the armature 6 will remain in engagement with the core 10. When the current "falls to a safe value, the spring 18 will overpower the force of the magnetic field of the core 4 and cause the closing of the contact members 24 and 26. In the event that the magnetic field becomes too weak to maintain the plunger 5 in actuated position, in opposition to the force of the spring 7, this spring 7 will reactuate the plunger 5 to its illustrated position (Fig. 1) causing the enlargement 11 to rengage the armature 6 and to reopen the contact members 24 and 26 in opposition to the force of the spring 18.

In Fig. 2, I have illustrated a control .system embodying the use of the relay of Fig. 1. For convenience, I employ the same reference numerals as in ,Fig. 1, wherever, possible. An armature 38, having a compensating field-magnet winding 39, a series field-magnet winding 40 and a shunt fieldmagnet winding 41 is connected between the line conductors 42 and 43 in series with a resistor 44. The circuit of the motor is adapted to be closed by the line contactor 45, and the resistor 44 is ada ted to be short-circuited by a plurality o contactors.

45, 45 and 45. The contactor 45 is actuated by a coil 52, and the contactors 45, 45. and 45 are actuated by coils 48, 49 and 50. A plurality of relays 6, 6 and 6 are shown as mechanically interlocked with the plungers 5, 5 and 5*, respectively, of the blowout coils of the contactors 45, 45 and 45" in such fashion that they will be maintained in the open position until released upon the occurrence of current peaks, as described in connection with Fig. 1. The system is shown as controlled by a pair of push-buttons respectively designated as start and stop The contactor 45 is mechanically interlocked with a switch 51 for short-circuiting the start push-button, as below described.

Upon the closing of the start? push-button, a circuit is established which extends from the line conductor 42, through the sto and start push-buttons, and the actuating coil 52 to the line conductor 43. The contactor 45 is thereupon closed, causing the closing also of the switch 51, which establishes a short-circuit -for the start.

push-button, so that the start push-button may thereupon be released. A circuit is now established for the motor which extends from the line conductor 42 through the coil 4-which controls the relay 6-the contactor 45, the armature 38, the field- magnet windings 39 and 40 and the resistor 44, to the line conductor 43. A shunt circuit is also established for the field-magnet winding 41. A heavy current is thus caused to flow through the blowout coil 4 which operates the plunger 5 and releases the relay 6.

The relay 6, though releaied mechanically,

upon the occurrence of current peak 1s, nevertheless, maintained in open position for a limited period of time until the current in the motor circuit falls to a previously selected safe value, as explained in connection with the description of Fig. 1. When the current falls to a sufliciently low value, the rela 6 010 w'es, as described in connection with ig. 1, whereupon a circuit is established from the line conductor 42, through the stop push-button, the relay 6 and the actuating coil 48 of the contactor 45*,to the line conducor 43. The closing of 'this circuit, causing the energization of the safe value, dependingupon the strength of the spring 18 (Fig. 1), connected to the relay 6", or the size of the air gap'14 1), the relay 6 will close, whereupon a an cuit will be established, which extends from the line conductor 42," through the stop push-button, the relay 6" and the actuating coil 49 of the contactor 45", to the line conductor 43. The contactor 45 will thereupon be closed to short-circuit another portion of the resistor 44, the coil ,4",which is then en-- ergized, serving also as-a blowout coil for the contactor 45"., In the same manner as described above, the relay 6 will close at the proper time to cause the energization of the.

coil 50 and the consequent closing of the contactor 45 to short-c rcuit the remaining portion ofthe resistor 44. The stop pushbutton serves to deenergize the various circuits and stopthe motor,

It will be understood that ,the circuits of Fig. 2 are illustrative only, and that my invention'is of essarily limite' to motor-accelerating systems. I desire, therefore, that my invention shall not be construed as limited except in so far as limitations maybe expressed in the appended claims.

claim as my invention:

1. The combination with a coil and a plunger slidable within the opening of said coil, of means for actuating said plunger outwardly from said opening when said coil is denergized, an armature controlled by said lunger, means controlled by said plunger or maintaining said armature adjacent to said coil, and-means for biasing said armature away from said coil.

neral application, not nectracted to sald core member, a rod movable with said plunger and slidably mounted in said longitudinal opening, an armature that is mova le relatively to said rod, means caraplunger adapted to be, at-

ried by said rod-for, controlling said arma ture and means for actuating sald armature.

4. In a switch mechanism, the combina tion. with acoil and a switch associated therewith, of a spring tending to close said switch, a spring-retracted lunger controlled by said coil for maintaining the switch open when the coil 'is deenergized and an armature for maintaining the switch open a predetermined time after the coil has been, energized. I

5. In a switch mechanism, the combination with a main switch having a blowout coil, of an auxiliary switch, a. spring-retracted plunger associated with the blowout coil for maintaining the auxiliary switch in an open position, and an armature conswltch and associatedv nected to the auxilia with the blowout 0011 for maintaining the auxiliary switch in an open position a predetermined time after the blowout coil is energized and the auxiliary switch is released RAY E. DE CAMP.

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