US2040425A - Control mechanism - Google Patents

Description

J. L. BIACH May 12, 1936.

CONTROL MECHANISM Filed July 31, 19 51 2 Sheets-Sheet 1 INVENTOR.

JbH/v L. B/AcH, M,

A TTORNEYS.

Patented May 12, 1936 UNITED STATES PATENT OFFICE CONTROL MECHANISM Application July 31, 1931, Serial No. 554,223

9 Claims.

This invention relates to reclosing mechanisms and more particularly to a mechanism for closing an oil circuit breaker after the breaker has been open due to a short circuit or similar cause.

Certain features of the present application are disclosed and claimed in a copending joint application Serial Number 446,454 of Charles D. Geer and myself, the joint application and the present application having a common assignee.

No claims are made in the present application to such features, the claims herein being restricted to matter not disclosed in the joint application.

An object of this invention is to provide a mechanism which will reclose an oil circuit breaker at a predetermined time after the breaker is open.

A further object of the invention is to provide a reclosing mechanism which will reclose the oil circuit breaker one or more times if the short circuit persists.

A still further object of the invention is to provide a mechanism of the character described which will leave the circuit breaker open after it has tried to reclose it a certain number of times.

Another object of the invention is to provide an apparatus oi. the character described which will always provide a test period of a certain length of time before it returns to its normal condition.

An additional object is that of providing an apparatus of this character, the parts of which will be relatively few in number and each indi- 35 vidually simple and ruggedin construction, these parts operating over long periods of time with freedom from mechanical and electrical difficulties.

With these and other objects in mind, reference is had to the attached sheets of drawings illustrating a practical embodiment of the in- V vention and in which:

Fig. 1 is a plan view of a portion of the apparatus;

45 Fig. 2 is a side elevation thereof;

Fig. 3 is a transverse sectional view taken along lines 3-3 and in the direction of the arrows of Fig. 1 and Fig. 4 illustrates in a somewhat diagrammatic manner the action of the several elements of the apparatus and their relationship to each other.

Referring to Figs. 1 and 2, there is shown a shaft ll mounted in bearings l2 so that it may 55 rotate freely. Rigidly connected to shaft II is a toothed wheel l3. Also mounted on shaft II is a rocker-arm l4. This rocker-arm is actuated by magnet I5 through a link Hi. When magnet I5 is energized by applying a source of current to its leads I! and I8, plunger i9 is attracted to rotate the rocker-arm II in a counter-clockwise direction. Rotation of wheel I3 is prevented by means of dead pawl 20 which is pivoted at 2| and forced into engagement with wheel I3 by spring 22. Rotatively mounted on the end of 10 rocker-arm I4 is a live pawl 23 which is pressed into engagement with wheel l3 by means of spring 24. It will be noticed that as rocker-arm I4 is rotated counter-clockwise, live pawl 23 slips over the teeth of wheel I 3. The amount of 15 motion would be adjusted to be the distance subtended by one tooth. Thus pawl 23 will be brought into engagement with the next tooth, and when magnet I5 is deenergized, rocker-arm i4 is moved in a clockwise direction by spring 20 25. In returning to its rest position rocker-arm l4 through pawl 23 rotates wheel I3. An adjustable set screw 26 may limit the return motion of the rocker-arm l4. This operation can. now be repeated and will be noted that wheel l3 and consequently shaft I I will be rotated forward step by step. The magnet l5 together with the link mechanism and ratchet assembly may be considered a motor for rotating the camshaft.

Referring to Figs. 1 and 3, it will be noticed that the shaft ll carries a series of cams 21. These cams are provided with projections 28. Bearing against the surface of the cam is a spring strip 29 having a V-shaped projection 30. Mounted above spring 29 is a spring strip 3| and mounted on each of the strips are contacts 32. The strips are insulated from each other and mounted conveniently as at 33. Connected to the springs are leads 34 and 35. It will thus be noted that as the cam is rotated step by step, contacts 32 will be brought into engagement with each other when the projection 28 of cam 21 moves under the projection 30. When the low portion of cam 21 moves under the projection 30 the contacts will be separated. In this way circuit between wires 34 and 35 is open or closed depending upon the position of cam 21. By making the projections 28 subtend the distance of one or more teeth of wheel l3, the period of closure of circuit between wires 34 and 35 can be regulated.

As will appear below, four distinct positions are required, according to the present embodiment of the invention. This would make it nec- 56 essary for the rocker-arm II to move the wheel I 3 through an-arc of 90 degrees. While this is feasible, it is more convenient if a shorter arc can be utilized. This can be done by having Sev- 5 eral, for example, three complete cycles per revolution'. In this way a motion of only 30 degrees is necessary. It will be understood that the cam and toothed ratchet wheel shown are illustrative only. If a four position cycle repeated three times in one complete revolution of the camshaft is used as above indicated, a three projection cam as illustrated will be used with a 12 tooth ratchet wheel. On the other hand if for example a six position cycle repeated three 16 times is used, an 18 tooth ratchet wheel as illustrated is provided.

Referring to Figs. land 2, it will be noted that the rocker-arm, in addition to controlling the action of the switches or contacts, which are cam 80 operated, serves to cause a functioning of an additional pair of contacts. This may be achieved by, for example, having a pin 36 extending beyond the arm l4 and arranging in the path of travel of this pin a spring strip which 20 forms a part of a strip pair mounting contact ll. Leads and are connected one to each of the strips 31 and it is obvious that as the arm l4 moves in a counter-clockwise direction the circuit will be closed, while when the arm moves so in a clockwise direction the circuit will be opened.

The wiring diagram is shown in Fig. 4. A source of voltage supply is indicated at 4| and 42. The following description will be made on 8d the assumption that the available voltage is alternating current. Of course the apparatus may be constructed for direct current equally well. 43 represents a switch which is mounted on the oil circuit breaker (indicated in dotted lines).

go This switch is arranged to close the circuit between wires 44 and 45 when the oil switch is in the open position. Assuming that an overload or similar trouble occurs on the line controlled by the oil circuit breaker, the breaker will open as automatically and close switch 43. This will enwire II; Therectifler is being energized, it furnish'es direct current at its terminals 54 and 85.

I. represents the developed surface of the cams.

21. The cams are notched successively from position A to B to C to D and then back to A. A

55 is the resting or normal position and in this position contact 81 will be closed. When relay 48 operates it causes armature 58 to touch contact I. This establishes a circuit from one terminal II through wire 60, armature 5|, contact 59, wire 00- I, contact 61. resistance '62, wire 83, condenser.

44, and wires and 86 to the other terminal 84. It will thus be noticed that the direct current voltage of rectifier 49 is applied to the condenser 04 through the resistance 62. The condenser as. will thus be charged at a rate determined by the rectifier voltage, resistance 62 and the capacity of condenser 04. g

shunting the condenser is a circuit consisting of relay l1 and a glow-tube 68. This glow-tube comprises a settled bulb 89 into which the electrodes "ll extend. The bulb is filled with a suitable gas. The tube is characteristic that it is normally non-conducting, but when the voltage across its terminals reaches a certain predeter 16; mined value, the tube suddenly becomes conducting and remains conducting until the voltage has dropped considerably below the critical ionizing voltage.

It will be appreciated that many values may be chosen, but by way of example the following values have been found suitable. The rectifier direct current output may be 412 volts. The condenser 64 may be a 5 m. f. condenser. It will be appreciated that the voltage across the terminals of condenser 64 will gradually build up according to the formula in which E represents the voltage across the condenser at any time t, E0 the voltage impressed across the condenser charging circuit, R. the resistance of the charging circuit in ohms, C the capacitance of the condenser in farads, and e the Naperian logarithmic base of value 2.718. The glow-tube may have a critical ionizing voltage of 260 volts. It will therefore be appreciated that the condenser voltage will reach the critical ionizing voltage of glow-tube 68 at a time in seconds which equals the value of resistance 52 divided by 200,000. For example, if resistance 82 is 200,000 ohms, the condenser will charge to the critical voltage in one second. If

resistance 62 is 1 million ohms, the time required will be 5 seconds, etc.

When the glow-tube becomes conducting the energy stored in condenser 64 discharges through glow-tube 89 and relay 61, operating'relay 81 momentarily. This closes a circuit through wire Il, armature 12, contact 13, wire ll, solenoid i5 and wire l8, operating solenoid i5. Solenoid I I cooks the notching mechanism. Most of the energy stored in condenser 54 has been utilized in the momentary operation of relay 61. However, to make sure that no energy remains in condenser 64, solenoid i5 when completely energized closes circuit between wires 39 and 40 which shunts a low value resistance 14 across the con--' denser 84, completely discharging the condenser,

Glow-tube 69 becomes non-conducting and relay 8! drops to itsdeenergized position. This breaks the energizing circuit of solenoid I! which drops to its deenergized position. In doing so the notching mechanism moves the cams to position .8. While relay 51 was energized it momentarily closes circuit between wires I5 and 18. This circuit may be used to operate the closing mechanism of the circuit breaker and thus the circuit breaker is reclosed.

In position B contact 11 is closed maintaining the energizing circuit of rectifier 49. It will be appreciated that this contact is closed in positions 3, C and D. This may be achieved by having the switch therefor cooperate with one of the cams positioned upon the shaft II, or by mounting an additional cam upon the shaft. Thus, whether or not relay 46 is energized or deenergized, the mechanism continues to function.

Assuming the o erload or short circuit to persist on the line, the circuit breaker will again open. In position B there is provided a charging circuit from terminal 55 through wire 18, contact in position C. The new charging circuit thus provided goes through contact 8| and resistance 82 instead of contact 19 and resistance 80. At a time determined by resistance 82 the notching operation will again repeat, reclosing the circuit breaker another time and notching the cams to position D. Assuming that the circuit breaker again opens, it will be noticed that in position D the only contact closed in the charging circuit for the condenser is contact 83. Due to the fact that relay 46 is energized, armature 58 will not be touching contact 84, and thus no charging circuit for condenser 64 will exist. Thus no further notching operation takes place. The oil circuit breaker remains open and has to be reclosed by hand, presumably after the trouble has been remedied. After it has been put in by hand, switch 43 will open and relay 46 becomes deenergized. This establishes the charging circuit through contact 84 and contact 83 and resistance 84. After a time determined by resistance 84 the notching operation again occurs and the cams return to position A, the rectifier becomes deenergized and the apparatus returns to normal.

It will thus be noted that there is provided an apparatus which recloses the circuit breaker three times, but after the third time leaves the breaker open until the trouble has been remedied. However, after the circuit breaker has been closed by hand the machine times a protective period (as determined by the resistance 84), before it returns to the normal rest position. If the trouble is only a temporary one and the breaker remains in after the first, second or third reclosing, then the apparatus, after going through its cycle and providing the protective period, returns to normal. As a rule this protective period is two minutes or more and thus, if the breaker remains in for a period of two minutes or more it may be assumed that the trouble has passed.

It will be appreciated that the apparatus may be arranged for only two reclosings by omitting position C on the cams. Similarly, additional reclosings may be provided by additional cam positions. If for any reason it is desired that the circuit breaker should be intentionally opened, means may be provided to disconnect the reclosing mechanism from the circuit so that repairs or tests may be accomplished without interference or annoyance. It will also be apparent that any number of changes in construction and rearrangement of the parts might be resorted to with- .out departing from the spirit of the invention asdiefined by the claims.

Having described my invention, what I claim as new and desire to secure by Letters Patent is: 1. A control mechanism for association with circuit breakers, said mechanism including means controlling a closing of the circuit breaker, means for actuating said controlling means a plurality of times, means connected to said apparatus for initiating the operation of said controlling means in response to an initial opening of said circuit breaker, said mechanism in response to such initial opening operating cyclically to provide such plurality of control actuations, means responsive to an' opening of the circuit breaker after such plurality of closing actuations to render said mechanism ineffective to provide further closing actuations; and means forming a part of said mechanism for restoring the same to its initial condition responsive to said circuit breaker being manually closed and remaining closed for a predetermined period to operate through a second cycle responsive to' a further actuation of the circuit breaker with which said mechanism is associated.

2. A control mechanism for association with circuit breakers, said mechanism including a switch which when closed causes a closing of the circuit breaker, a motor, a second switch actuated by an initial opening of the circuit breaker with which said mechanism is associated and connected to said motor to initiate the operation thereof, an electromagnet connected to said first named switch to control the actuation thereof, a flash tube in series with said electromagnet, a condenser in shunt with said tube and electromagnet, a plurality of resistances connected to said condenser, and means operated by said motor to sequentially connect said resistances to a source of electrical current supply whereby during such motor operation said electromagnet will be periodically energized to actuate said first named switch a predetermined number of times.

3. A control mechanism for association with circuit breakers, said mechanism including a switch which when closed causes a closing of the circuit breaker, a motor, a second switch actuated by an initial opening of the circuit breaker with which said mechanism is associated and connected to said motor to initiate the operation thereof, an electromagnet connected to said first named switch to control the actuation thereof, a flash tube in series with said electromagnet, a condenser in shunt with said tube and electromagnet, a plurality of resistances connected to said condenser, means operated by said motor to sequentially connect said resistances to a source of electrical current supply whereby during such motor operation said electromagnet will be periodically energized to actuate said first named switch, and means connected to said electromagnet to short circuit said condenser each time said electromagnet is energized.

4. A control mechanism for use in association with a circuit breaker, said mechanism including means responsive to an opening of the breaker to provide an impulse for automatically reclosing the same, means functioning after a predetermined initial condition only after the expiration of an interval of time after said circuit breaker has been manually re-closed.

5. A control mechanism for association with a circuit breaker and including a shaft, a motor connected to said shaft to intermittently move the same, cams mounted upon said shaft, switches sequentially actuated by said cams, means responsive to the actuation of said switches to control the time period elapsing'before the next intermittent movement and to give an impulse for reclosing the circuit breaker upon the latter opening, and means responsive to an initial opening of the circuit breaker for initiating'operation of the motor.

6. A control mechanism for association with a circuit breaker, said mechanism including a motor, a shaft connected to said motor to be intermittently moved thereby, cams secured to said shaft, switches sequentially actuated by said cams, means connected to said switches and controlling the interval of time elapsing between one movement of the shaft and a succeeding movement thereof, means also connected to said switches for giving an impulse for reclosing the circuit breaker, and means connected to said motor to initiate an operation thereof in response to an initial opening of said circuit breaker.

7. A control mechanism for association with circuit breakers, said, mechanism including a means controlling a closing of the circuit breaker, operating means for operating said controlling means a plurality of times, means connected tosaid circuit breaker for initiating the cycle of operations of said controlling means in response to an initial opening of said circuit breaker, and timing means including a condenser and means for varying the charge on said condenser and means operable upon the charge on said condenser reaching a predetermined value cooperable for predetermining the time interval between such actuations, a plurality of control circuits for governing said timing means to time different intervals, and selective means operated by said operating means upon each operation of said controlling means to connect another one of said control circuits to said timing means to provide an appropriate time interval.

8. A control mechanism for association with a circuit breaker and including a shaft, a motor connected to said shraft to intermittently move the same, cams mounted upon said shaft, switches sequentially actuated by said cams as said shait moves, means operable a predetermined time after the actuation of each of a plurality of said switches to reclose the circuit breaker upon the latter opening and to actuate said motor to move said shaft to actuate the next of said switches, and means responsive to an initial opening of the circuit breaker for initiating operation of the motor to actuate the first of said switches.

9. A control, mechanism for use in association with a circuit breaker, said mechanism including means responsive to an opening of the breaker to provide a series 01 impulses for automatically reclosing the same separated by predetermined time periods, said means including a condenser, means for charging said condenser, a flash tube and a relay in series across said condenser and operable when said condenser reaches a predetermined charge to give the impulse for reclosing said circuit breaker, a plurality of control circuits to govern the charging time said condenser and thus to govern said time periods, and means operated by said relay to disconnect one control circuit and connect another when said relay operates to give the reclosing impulse.'

JOHN L. BIACH.

Images