US1474991A - Circuit controller - Google Patents

Description

Nov.'20,1'923. 1,474,991

c. w. YERGER CIRCUIT CONTROLLER Filed April 9. 1921 INVENTOR.

B in

A TTORNEY Patented Nov. 20, 1923.

UNITED STATES 1,474,991 PATENT OFFICE.

CHARLES W. YERGER, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO THE CUTLER-HAM- MER MFG. CO., OF MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

CIRCUIT CONTROLLER.

Application filed April 9, 1921. Serial No. 460.114.

To all whom- :it may concern:

Be it known that I. CHARLES W. Ynnonn. a citizen of the United States, residing at Boston, in the county of Suffolk and State of Massachusetts, have invented new and useful Improvements in Circuit Controllers, of which the following is a full, clear, concise, and exact description, reference being bad to the accompanying drawing, forming a part of this specification. i

This invention relates to circuit controllers particularly advantageous for controlling electric motors although not limited to such use.

Where sequentially responsive electromagnetic switches are employed for accelerating an electric motor, it is often desirable to delay response of each switch for a definite time following response of the preceding switch to insure smooth acceleration and to afford a degree of protection to the controlled motor. To so time the response of the several switches, it, has heretofore been proposed to employ a common control device therefor to complete the circuits thereof sequentially, such device being retarded in its operation as by av dash pot and as an alternative it has been proposed to provide each switch with a dash pot to delay response thereof. However, both proposals have been found to be open to numerous objections including the unreliability of dash pots when used in the aforesaid relations and particularly when used to directly! control switches of the size and character required for motor acceleration. Moreover the single control device fails to provide for independent adjustments of the time elements of the several switches.

The present invention has among its objects to provide a controller for the aforesaid and other purposes having improved means of a simple and efficient character to definitely delay response of the desired switches.

Another object is to provide a controller of the aforesaid character wherein the means for delaying response of the switches permit of independent time adjustments for the several switches.

Another object is to provide a controller of such design that the desired delays may be accomplished by dash pots so employed as to render use thereof entirely practicable.

Another object is to provide for attainthat the embodiments illustrated are susceptible ofvarious modifications without departing from the scope of the appended claims.

In the drawing,

Fig. 1 diagrammatically illustrates a controller for an alternating current motor;

and

' Fig. 2 diagrammatically illustrates a con troller which may be used for either direct or alternating current motors.

Referrino to Fig. 1, the same illustrates in a simplified form a controller including lectro-magnetic switches 1, 2 and for startlng and accelerating an alternating current motor M of any preferred type. The switch 1 serves to connect the motor across alternating current supply lines L and L through resistances R and R while switches 2 and 3 serve to respectively short-circuit sald resistances. As will appear, the energizing circuit of switch 2 is controlled by auxiliary contacts 1 of switch 1 while the energizing circuit of switch 3 is controlled by auxihary contacts 2 of switch 2 whereby the switches 1, 2 and 3 are insured response sequentially in the order named.

The controller also includes relays 4 and 5 to respectively delay response of switches 2 and 3. These relays are of like construstion, each comprising a switch arm 6 pivotally supported by magnet frame 7 and normally engaging a fixed contact 8. The magnet frame 7 has mounted thereon a Winding 9 which when energized attracts the switch arm 6 away from contact 8 and said frame also has mounted thereon a dash pot 10 connected to the switch arm to oppose its-return into engagement with contact 8. These relays control comparatively small currents and may therefore be designed to function. in a positive and reliable manner under control of any one of numerous known types of dash pots capable of. adjustment and capable of functioning as described without opposing attraction of the switch arm by the winding 9. The relay 4 controls the energizing circuit of switch 2 while the relay 5 controls the energizing circuit of switch 3.

The winding 9 of relay 4 is connected in series with the winding of switch 1 while the winding 9 of relay 5 is connected in serieswith the winding of switch 2. Thus by properly proportioning the relay windings with respect to the windings of switches 1 and 2, each relay winding w1ll be subjected to aheavy inrush of current upon inl'tial closure of its circuit subject to a material reduction in current upon response of the switch 1 or 2 as the case may be. As will be understood the current supplied to each of the relay windings will be reduced as the impedance provided by its series connected winding increases whereas such impedance varies inversely as the air gap of the magnet involved, with the result aforestated. In practice each relay is designed to respond to attract its contact arm out of engagement with its co-operating contact upon completion of its energizing circuit and to release its contact arm upon response of the switch to which its winding is connected.

It will thus be apparent that upon closureof the energizing circuit of switch 1, relay 4 will respond to disengage its contacts for interruption of the energizing circuit of switch 2 and that upon response of switch 1 said relay will re-engage its contacts subject to retardation of the dash pot 10 to complete the circuit of switch 2. Likewise it will be apparent that upon completion of the circuit of switch 2, relay 5 will be energized to disengage its contacts for interruption of the energizing circuit of switch 3'and that upon response of switch 2 said relay will re-engage its contacts subject to retardation by its dash pot to complete the circuit of switch 3. Thus the relay 4 provides for delaying response of switch 2 for a definite time after response of switch 1, the delay being determined by the adjustment of the dash pot whereas relay 5 delays response of switch 3 for a definite time after response of switch 2, this delay being determined by the adjustment of the dash pot of the latter relay. The relays accordingly provide for independent time adjustments for the switches 2 and 3.

The circuit connections are as follows. The motor circuit extends from line L by conductor 11 through switch 1 and resistances R and R by conductor 1.2 to and through the motor by conductor 13 to line L it being apparent that switches 2 and 3 respectively control short circuits around resistances R and R The energizing circuit of switch 1 extends from line L through v a suitable control switch 14 by conductor 15 to and through the winding of said switch 1 by conductor 16 through the winding 9 of relay 4 by conductor 1? to line L The energizing circuit of witch 2 extends from switch 14 by conductor 18 through auxiliary contacts 1 of switch 1 by conductor 19 to and through the magnet frame of relay 4 and its contacts by conductor 20 to and through the winding of switch 2 by conductor 21 to and through the winding 9 of relay 5 by conductors and 17 to line L The energizing circuit of switch 3 extends from switch 14 by conductor 18 to and through the auxiliary contacts 2 of switch 2 by conductor 23 to and through the magnet frame of relay 5 and its contacts by conductor 24 through the winding of switch 3 by conductors 25 and 17 to line L Referring to Fig. 2, the same illustrates similar electro- magnetic switches 30, 31 and 32 for starting and accelerating a direct or alternating current motor M shown as provided with an armature a and series field The switch 30 serves to connectthe motor M across supply lines L and L" through resistances R and R while switches 31 and 32 serve to respectively short-circuit said resistances, the motor connections being substantially the same as in Fig. 1. Switches 30 and 31, like switches 1 and 2 of Fig. 1, are provided with auxiliary contacts 30 and 31 to interlock switches 30, 31 and 32 for response sequentially. Also switches 30 and 31 are respectively provided with auxiliary contacts 30" and 31 which normally short-circuit resistances r and 1", each of such sets of auxiliary contacts being disengaged upon response of the switch with which the same are associated. The resistances 1' and r are provided for inclusion in circuit with the windings of switches 30 and 31 respectively upon response of said switches to reduce the flow of current through their windings or in other words to serve as protective resistances.

Also this controller includes relays 33 and 34 of the same construction as the relays 4 and 5 of Fig. 1. The relays 33 and 34 have their operating windings respectively connected in series with the windings of switches 30 and 31 and said relays respectively control the energizing circuits (it switches 31 and 32.

Inthis form of controller the winding of relay 33 will be subjected to a relatively heavy inrush of current upon completion of the energizing circuit of switch 1 whereas the current supplied to said relay winding will be reduced upon response of switch 1 and consequent inclusion of protective resistance 7". Likewise the operating winding of relay 34 will be subjected to a relatively heavy inrush of current upon completion of the energizing circuit of switch 31 whereas the current supplied to said relay winding will be decreased upon response of switch 31 and consequent inclusion of protective resistance 1". Thus these relays will function similarly to the rela s shown in Fig. 1 to delay response of t e resistance controlling switches the onl essential difference between the control ers residing in the manner in which the current supplied to the relay windings is reduced for release of said relays.

The energizin circuit of switch 1 extends from line L t rough a suitable control switch 35 by conductor 36 to and through the winding of switch 30 by conductor 37 to and through auxiliary contacts 30 by conductor 38 to and through the Winding of relay 33 by conductor 39 to line L, the protective resistance 1" being included in said circuit upon response of switch 30.

The energizing circuit of switch 31 extends from switch 35 by conductor 40 through the auxiliary contacts 30 of switch 30 by conductor 41 to and through the magnet frame of relay 33 and its contacts by conductor 42 to and through the winding of switch 31 by conductor 43 through the auxiliary contacts 31 by conductor 44 to and through the winding of relay 34 by conductors 45 and 39 to line L. The energizing circuit of switch 32 extends from switch 35 by conductor 40 through auxiliary con tacts 31 of switch 31 by conductor 46 to and through the magnet frame of relay 34 and its contacts by conductor 47 to and through the winding of switch 32 by conductors 48 and 39 to line L.

What I claim is new and desire to secure by Letters Patent is:

1. In a circuit controller, in combination, an electro-responsive switch acting upon response thereof to reduce the flow of current in its energizing circuit and an electroresponsive relay having its winding con nected in series with the winding of said switch for energization therewith, said relay being adjusted to release upon reduction of current in its circuit by response of said switch.

2. In a circuit controller, in combination, anelectr0-responsive switch acting upon response thereof to reduce the flow of current through its winding circuit and an electroresponsive relay having its winding connected in series with the winding of said switch for energization therewith, said relay being adjusted to release upon reduction of current in its circuit by response of said switch and having means to delay its return to normal position.

3. In a circuit controller, in combination, a plurality of electromagnetic switches and an electro-responsive relay controlling one of said switches, said relay having its wind ing connected in series with the winding of another of said switches for energization therewith and the latter switch upon responding effecting reduction of the current supplied to said relay winding to effect release of said relay. 4. In a circuit controller,-in combination, a plurality of electro-responsive switches interlocked to respond sequentially and an electro-res )onsive relay responsive to delay energization of one of said switches, said relay having its operating winding connected in series with the operating winding of a preceding switch for energization therewith and for release by response of said preceding switch.

5. In a circuit controller, in combination, a plurality of electro-responsive switches to respond sequentially and an electro-responsive relay controlling one of said switches and normally occupying a position rendering the latter responsive upon response of a preceding switch, said relay having its operating winding connected in series with the winding of said preceding switch for energization therewith, said preceding switch upon responding effecting release of said relay and said relay having means for retarding its return to normal position.

6. In a circuit controller, in combination, a plurality of electro-responsive switches to respond sequentially, the first responsive switch having an energizing circuit wherein the flow of current is decreased by response of said switch and an electro-responsive relay controlling a succeeding switch and having its operating winding connected in the energizing circuit of said first responsive switch.

7. In a circuit controller, in combination, a plurality of electro-responsive switches interlocked to respond sequentially, one of the said switches having an energizin circuit wherein the flow of current is reduced by response thereof and an electro-responsive control relay for a succeeding switch responsive to prevent energization thereof and tending when de-energized to render said succeeding switch responsive, said relay having its operating winding connected in the energizing circuit of the first-mentioned switch and having means for retarding its return to normal position when released by the reduction of current effected by response of the first-mentioned switch.

8, In a circuit controller, in combination, a plurality of electro-magnetic switches interlocked to respond sequentially, certain of said switches having independent energizing circuits wherein the current is reduced by response thereof, and a plurality of electro-responsive relays individually controlling certain ofsaid switches, each of said relays having its operating winding connected in the energizing circuit of a preceding switch to be subjected to the varying current thereof for delaying response of the switch which it controls.

9. In a circuit controller, in combination, a plurality of electro-responsive switches to respond sequentially, one of said switches acting upon response thereof to lncrease the impe ance of its energizing circuit and an electro-responsive relay controlling a later responsive switch and having its operating winding connected in series with said first-mentioned switch to be energized therewith and to be released upon the increasein impedance of its circuit effected by response of said first-mentioned switch.

10. In an alternating current circuit controller, in combination, a plurality of electroresponsive switches having operating windings supplied with alternating current and an electro-responsive relay for controlling one of said switches, said relay having its winding connected in series with the winding of another of said switches to be energized therewith and to be released by the reduction in current supplied thereto due to the increased inductance of the winding of the last-mentioned switch upon response of the latter.

In witness whereof, I have scribed my name.

' CHARLES W. YERGER.

hereunto sub-

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