US1980142A - Regulating device using copper oxide rectifiers - Google Patents

Description

Nov. 6, 1934. B. E. OHAGAN 1,980,142

REGULATING DEVICE USING COPPER OXIDE RECTIFIERS Original Filed Oct. 14, 1930 /5Z l 50 16 5 M r ..l

5 E 1 a 4 i 52 59" bnw fiwmaizap INV NTOR B ernard E. 519G901? BY 12W H18 A TTORNEY Patented Nov. 6, 1934 UNITED STATES PATENT OFFICE REGULATING DEVICE USING COPPER OXIDE RECTIFIERS Bernard E. OHagan, Swissvale, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania 3 Claims.

My invention relates to regulating devices using copper oxide rectifiers.

I will describe one form of apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a curve showing certain electrical characteristics of a copper oxide rectifier. Fig. 2 is a diagrammatic view showing one form of apparatus embodying my invention.

The present application is a division of my copending application Serial No. 488,574, filed October 14, 1930, Patent No. 1,966,558, granted July 17, 1934, for Regulating devices using copper oxide rectifiers. Referring first to Fig. 1, the curve shown in this view illustrates the voltage-resistance characteristic of the copper oxide rectifier described and claimed in United States Letters Patent No. 1,640,335, granted to L. O. Grondahl on August 23, 1927. This curve shows that as the voltage across the rectifier increases, the resistance in the low resistance direction decreases, and that the decrease of resistance is much more rapid at low voltages than at high voltages.

Referring to Fig. 2, the reference character A designates a railway switch which is actuated by an electric motor M having an armature l and a field 2. Operatively connected with the switch is a cut-out controller D comprising a contact arm 59 and contacts 3 and 4. Contact 359 remains closed at all times except when the switch is in the reverse position and contact 459 remains closed at all times except when the switch is in the normal position.

The motor M is controlled in part by a circuit controller P which is in turn controlled by a pole-changer L which may be incorporated in a switch lever of an interlocking machine. The circuit controller P comprises an electromagnet 9, made up of two windings 9 and 9 and a. polarized winding 10 which is preferably provided with a steel permanently magnetized core 11. Pivotally attached to the core 11 is an *armature 12 which is therefore polarized by flux from the permanent magnet core 11 at such times as winding 10 is not carrying current. It follows that when the electromagnet 9 is sup- -plied with current of one polarity the armature 12 will be swung in a clockwise direction, but that when current of the opposite polarity is supplied to electromagnet 9 the armature will be swung in the opposite direction. The armature 12 controls three movable contact yokes 13, 14 and 15 through suitable linkage, in such manner that the yokes occupy their right-hand positions when the armature is swung to the left, and vice versa.

The reference character N designates a neutral magnet which controls a pivoted armature (39 1'7, the lower end of which projects into the path of movement of a portion of armature 12 to prevent the reversal of the armature when the neutral magnet N is deenergized. Pivotally attached to the armature 17 is a link 19 provided with a slot 42 which at times engages a pin 43 in a rocker arm which carries a contact finger 20. When magnet N is deenergized, the link 19 moves the rocker arm '70 against the bias exerted by spring 44 into a position in which the contact 20 connects wire 33 with wire 34. When neutral magnet N is energized, however, the spring 44 urges the rocker arm 70 into a position wherein the contact between wires 33 and 34 is interrupted. As shown in the drawing, the switch A occupies its normal position; the neutral magnet N is deenergized thereby locking armature 12 of circuit controller P in its left-hand position.

The apparatus thus far referred to in Fig. 2 is illustrated and described in United States Letters Patent No. 1,722,364, granted to Henry S. Young on the 30th day of July, 1929, for Railway traffic controlling apparatus.

The reference character R designates an automatic circuit breaker. Circuit breaker R comprises a primary core 25 on which are windings 23 and H, and a secondary core 24 on which is a winding H Associated with core 25 is an armature 21 which is normally held open by rod 27 due to the action of compressed spring 22 and at times due to the attraction of armature 26 to the face of core 24. Rigidly attached to rod 27 is a detent 5'7 which raises link 19 when armature 21 is attracted. When link 19 is raised, pin 43 is disengaged from slot 42 and rocker arm 70 moves to the right, due to the bias exerted by spring 44, moving contact finger 20 to the right and thus breaking contact between wires 33 and 34. In series with coil 23 is a rectifier 40, and both coil 23 and rectifier 40 are connected across field 2 of motor M. Coil 23 and rectifier 40 are connected across field 2 through wire 32, rectifier 40, wire 32 winding 23, and wire 35. Coil 23 is energized by the voltage drop across field 2.

In order to prevent tripping circuit breaker R, when power is first applied to motor M and the drop across field 2 is high, the circuit switch now moves to the reverse position. obstruction occurs in switch. A, the motor runs and the voltage drop across field 2 decreases.-

If the switch becomes obstructed while moving to the normal or reverse position so that the motor runs at a low speed, due to the slipping of the motor clutch, the voltage drop across field 2 willincrease and when the'voltage drophas increased beyond a certain value, the resistance of rectifier will decrease. to .a point, where sufficient current will flow through coil 23 to at tract armature 21 and trip the circuit breaker.

Motor M has a normal and a reverse operating circuit, and its direction of rotationdepends on the position of contact 59 of circuit controller D and yokes .13, 14. and 15.. When the switch is to bemoved to the reverse position, the motor operating circuit is from terminal B, through wire 5 wire 33,.contactfinger 20,. wire 34, wire 28, yoke 13, wire 16, armature 1, wire 18, yoke 14, wire 31, contact 3, contact 59 and field 2 to terminal C. Whenthe switch is to be moved. to the normal position, the. motor operating circuitis from terminal B, through wire 5 wire 33, contact finger 20, wire 34, wire 29, yoke 14, wire 18, armature 1, wire 16-, yoke 13, wire 30, contact 4,'conta'ct. 59 and field 2 to terminal C.

In describing the operationv of the apparatus, I will assume it is desired to move switch A to the reverse position. Pole-changer L is first reversed and current flows from terminal B,

through wire 7, yoke 15, neutral magnet N, and

wire 6 to terminal 0. Neutral magnet N is energized 'and armature 17 is attracted, closing suitable contacts to energize polar relay P in the reverse direction. Armature 12 then moves to the right, moving yokes 13, 14 and -15 to the left, closing contacts which complete the motor circuit when armature 1'? is released connecting wires 33 and 34 through contact finger 20-. The If an at a low speed and the voltage across field 2 increases beyond a value necessary to decrease the resistance of rectifier 40 for sufficient current to flow through winding 23 to attract armature 21. Detent 57 will then raise link 19 and slot 42 will "disengage from pin 43. Rocker arm will move to'the right due to the bias exerted by spring 44 and the contact between wires 33 and 34 will. open, opening the motor circuit.

The circuit breaker. once having been tripped will not reset until the controller-P has moved to the opposite posit-ion. Resetting controller P is accomplished by moving pole-changer L to the posit-ion shown on the drawing. Current will now flow from terminal B, through bus 5, wire 8, yoke 15, neutral magnet N, and wire6 to terminal 0. Magnet N is energized and attracts armature 1'7 which moves link 19 so that slot 42 engages pin 43. Suitable contactsare closed when armature 17 is attracted to energize polar relay P in the normal direction. A-rmature 12 thenmoves tothe left, moving yokes 13, i l and 15 to the right and closing contacts which complete the motor circuit for reverse rotation'when armature 17 is released connecting wires 33 and 34 through contact finger 20. When the switch returns to the original position,

the operation maybe repeatedasfirst described.

In a similar manner if the switch is to be moved from the reverse position to the normal position, the pole-changer L is moved to the position shown in Fig. 2. Magnet N is then energized and armature 1'7 is attracted, closing suitable contacts to energize polar relay P in the normal direction. Armature 12 then moves to the left, moving yokes 13, 14 and 15 to the right, closing contacts which complete the motor circuit' when armature 17 is released connecting wires'33 and 34 through contact finger 20. The switchnowmoves to the normal position. If an obstruction occurs in switch A while it is moving to the normal position, the resistance of rectifier 10 will be decreased due to increased I voltage across'field 2, causing breaker R to trip, as previously described, thus protecting motor M1 To return theswitch to the reverse position,

pole-changer L will again be reversed, energizing 'magnet N and reversing controller P, in the manner previously described. After the switch returns to the reverse position, another attempt to move the switch to the normal position can be made.

With apparatus embodying my, invention shown inFig. 2 it is possible to restore the-switch to its last operated position immediately and to attempt to operate the movement again in the direction in which it failed.

The main feature of my invention is that since a copper oxide rectifier has the electrical characteristicof lowering its resistance-When the voltageacross it increased, the rectifier may be used as a regulating device in the manner described. One advantage resulting, from the use of acopper oxide'rectifier Pin the manner described is that, because of the greater resistance change for a given voltage change obtainable with the rectifier as compared "with the resistance change of the usual ballast lamp :or negative temperature coefficient resistor, a device more sensitive in operation and possessing a greater possible range of adjustment isrnade available. Another advantage is that :since the copper oxide rectifier is practically instantameous in its response to voltage changes, as contras-ted with devices in which a resistance change follows upon a temperature change, are- ;quiring an appreciable time interval, the speed of operation of the system .is increased. It will, of course, :be understood that my :i-n-

vention is not limited tower-load .;protecfion of a railway switchmotor, but may be applied to the control of any load circuit "in which :itis

desired to maintain the, load currentaccurately :below a given predetermined value, aslight =increasethe load current above the given value being sufiioient :to causeithe-breaker to respond. .zfllthollgh'. 1a series motor :is illustrated, ';a shunt motor or other suitable; type of motor can-ob- :viously be protected as Well, since the-trip windi-ng 2350f breaker R does .not have, to be con- -nected across the'motor field, but may :be non- 'nected across any suitable impedancein series with the motor. In ascriesmotor, the-connec- ,tion across the field is convenient sinceno additional impedance .is required for obtaining (the .potential drop usedsfor operating the breaker.

-Although :I have herein shown and described .:-only one form of apparatus embodying ,my in-,

Having thus described my invention, what I claim is:

1. In combination with an electric motor having an armature and a field winding, a circuit for energizing said motor, an overload breaker for at times interrupting said circuit, means for tripping said breaker including a trip winding energized from the potential drop across the field winding of said motor, and a copper oxide rectifier connected in series with said trip winding for causing a relatively large increase in the current through said trip winding with a relatively small increase in said potential drop resulting from an overload on the motor, thereby providing for sensitive overload operation 01' said breaker.

2. In combination with an electric motor having an armature and a field winding, a circuit for energizing said motor, an overload circuit breaker for at times interrupting said circuit, and means for tripping said breaker including a trip winding energized from the potential drop across the field winding of said motor.

3. In combination with an electric motor having an armature and a field winding, a circuit for energizing said motor, an overload circuit

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