US768214A - Electric switch and circuit-breaker. - Google Patents

Description

No. 768,214. PATENTEI AUG. 23, 1904. C. B. CARPENTER.

ELECTRIC SWITCH AND CIRCUIT BREAKER.

APPLICATION FILED JAN. 16, 1904.

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C. E. CARPENTER. ELECTRIC SWITCHAND CIRCUIT BREAKER.

APPLICATION FILED JAN. 16,1904..

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PATENI'ED AUG. 23, 1904.

C. E. CARPENTER. ELECTRIC SWITCH AND CIRCUIT BREAKER.

APPLICATION FILED JAN. 16, 1904.

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UNITED STATES PATENT DEUCE CHARLES E. CARPENTER, OF NEW YORK, N. Y., ASSIGNOR TO THE CUTLER-HAMMER MFG. CO., OF

MILWVAUKEE, WVISCONSIN, A

CORPORATION OF WISCONSIN.

ELECTRIC SWITCH AND CIRCUIT-BREAKER.

SPECIFICATION forming part of Letters Patent No. 7 68,214,

dated August 23, 1904.

Application filed January 16, 1904. fien'al No. 189,302. (No model.)

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Be itknown that I, CHARLEs E. CARPENTER, a citizen of the United States of America, and a resident of the city, county, and State of New York,have invented certain new and useful Improvements in Electric Switches and Circuit-Breakers, of which the following is a specification.

This invention relates to a circuit-breaker for electric current, and is designed especially for the emergency interruption of motor-armature circuits.

It is combined with a hand-operated motor starting and controlling switch by which the motor is started, controlled, and stopped in' such manner that upon the operation of the circuit-breaker from any cause it will not again close until the starting-switch has been restored to its starting or initial position.

There are several emergency devices for etfecting the operation of the circuit-breaker. These include an under potential magnet arranged to open the circuit-breaker when the line-potential falls materially or the supply of current ceases, an overload-magnet arranged to operate when thearmature-current becomes excessive, and hand-operated devices, one of which is operated by the restoration of the starting-switch to its initial position.

The circuit-breaker is provided with an improved form of magnetic blow-out, and this blow-out is combined in a common magnetic circuit with the overload-magnet and its armature, whereby the blowout is intensified on the operation of the overloadmagnet, since under such conditions of the operation of the circuit-breaker the heaviest currents are to be broken and the arc extinguished. The combination of these elements materially simplifies the apparatus, as there is one magnetic circuit and one energizingcoil for both, and there is less waste of electrical energy than there would be if separate coils were employed for the blow-out and the overload device.

A brake-load resistance is combined in the circuits of the system for slowing down and stopping the motor quickly.

In the accompanying three sheets of draw-' ings, which form a part of this application, Figure 1 is a front view of a slate with my circuit-breaker, starting-switch, and other apparatus mounted thereon, and combined with this is a diagram of the circuits therefor. Parts of the contacts controlled by the overload-magnet and parts of the circuit-breaker are broken away and shown in section, as is also the brake-load resistance. Fig. 2 is an enlarged plan view of the circuit-breaker and parts directly connected therewith. Fig. 3 is a section on the line 111 III of Fig. 2, showing the overload magnet and contacts controlled thereby. Fig. et is a front view of a slate with a modified form of apparatus introduced mainly to illustrate a difi'erent device for controlling the closure of the circuitbreaker from the hand-operated switch.

The apparatus illustrated comprises a motor M, which is supplied from two leads A B through a line-switch L, a motor'starting and controlling switch and rheostat, and an independent eircuit-breaker for opening the armature-circuit in emergency through emergency devices which will be described in detail later. The motor has a shunt-field which in the drawings is independent of the contacts of the rheostat andmotor-starting switch and the circuit-breaker and is connected directly across the leads inside the line-switch, so that it will be open only when the line-switch is open. There is also a brake-load resistance K with connections for closing a second armature-circuit through this resistance independently of the line.

In the form illustrated in Figs. 1 to 3, inclusive, a slate slab l carries a metal stud 2, on which a lever 3 is fulcrumed. The lever is provided with an operating-handle 4: and is operated across a series of rheostat-contacts 5. Resistance-sections 6 are connected to these -contacts.. -"The slate also carries a circuitpiece is drawn against the posts and electrical connection is established between the posts. Connection is also made when the magnet is energized between two contacts 11 and 12 in parallel with the circuit between the posts, contact 11 being connected with post 7 and contact 12 being connected with post 8. Contact 11 is mounted on alever 13, which is connected through a link 14: to the magnetarmature, and contact 12is mounted in a barrel 15, which is attached to the slate, and this contact has a slight movement in the barrel and is forced to its outward position by a spring 16 in the barrel. In consequence when the relay-magnet armature is released the connection between the posts 7 and 8 is broken first. The armature-current is thereby diverted to the contacts 11 and 12, and the final rupture of the circuit is between these latter contacts, since contact 12 follows contact 11 for a slight distance and an are or spark can 1 possibly form only between the contacts 11 and 12 and not between the contacts 7 and 8. These contacts 11 and 12 are located between magnet- poles 17 and 18, which form the stationary parts of a magnet which is magnetized by a coil 19 in the motor-armature circuit, and the poles of the magnet and the contacts are so placed with respect to each other that the magnetic lines of force between the poles will intersect the spark-gap, which is formed between the contacts 11 and 12 when they are separated.

I prefer the contacts tipped with iron, which I find to be superior to any other conducting material for the purpose on account of its infusibility and other properties. It is important, however, that the combined crosssection of the iron tips transverse to the lines of force across them should be small compared with the cross-section of the magnet and that they should be insufficient to conduct all of the magnetism, so that there will be some lines of force across the spark-gap between the contacts when they are separated. The magnetic circuit through the coil comprises the stationary parts 17 and 18, the former of which has a part forming a core which projects part way into the coil, and in addition a movable part of solenoid-armature which enters the other end of the coil through a hole in the part 18 and is normally kept at a distance from the stationary part 17 by a spring 20. This spring is so adjusted as to permit the operation of the armature only when the current-flow in the coil exceeds a safe amount for the motor-armature. It will be seen that the magnetic circuit has two gaps,

one between the armature and the opposing end of the core in the coil, the other gap forming the magnetic blow-out. By reason of the two gaps the magnetism produced by the fiow of current ordinarily required by the armature of the motor is insuflicient to operate the l solenoid-armature of this magnet; but the magnetism is suflicient for the prompt extinguishing of such arcs as may be formed between the contacts 11 and 12, except when there is an overload. hen there is an overload, the 1 operation of the solenoid-armature closes one of the gaps and the magnetism for blowing out the arc is more intense. The increased ampere-turns due to overload also greatly increase the intensity of the magnetic blowout. Operation of the solenoid-armature interrupts the circuit through the relay-magnet, thereby causing it to release and thereby operate the circuit-breaker.

The relay-magnet is energized by a controlling-circuit between the supply-leads which is independent of the armature-circuit. As illustrated, it is connected directly between the leads, and hence the magnet is wound with a great number of turns of fine wire, so as to have a sufiiciently-high resistance to withstand the voltage used. The magnet receives current direct from the supply-leads and is so adjusted that its armature will be released if there is any material fall in the potential be- 1 tween the supply-leads or cessation in the supply of current. The magnet thereforev acts I l as an under-potential emergency device to disconnect the motor-armature from the line. Interpolated in the circuit of the relay and under-potential magnet are several additional emergency devices for interrupting the magnet-circuit. These are in the form of pushbuttons 21, which when operated cause the magnet to release the circuit-breaker and open the motor-armature circuit. These push-buttons are usually placed at convenient points for the quick stopping of the motor independently of the operation of the starting switchlever. A push-button 22, also in this controlling-circuit, is located on the slate, so as to be engaged and operated by the lever of the starting-switch when this lever is brought to its initial position, which is the position indicated in dotted lines in Fig. 1. Upon such operation the motor-armature circuit is broken at the last resistance contact prior to the operation of this push-button, and there will be no current-flow through the circuit-breaker, but in mechanical combination with the circuit-breaker mechanism is a contact 23, which when the circuit-breaker is open bridges contact-posts 2 1 and closes the second armaturecircuit through the break-load resistance. The same contacts are thereby utilized for the closure of this circuit, whether the main circuit is opened by the operation of the circuitbreaker or by the operation of the lever of l the motor-starting switch.

henever the circuit-breaker is operated by any of the above-described emergency devices and the motor-starting lever is at a running position, a latch 25 mechanically engages a part of the circuit-breaker-operating mechanism and prevents its closure until the motor-starting switch-lever has been brought back sufficiently to engage an arm 26 of the latch and withdraw the latch. This arm is engaged by an insulated stud or roller 27, projecting from the lever. The circuit-breaker falls by gravity to its open position when released by the relay-magnet, and the latch falls by gravity into locking engagement with the collar 28 on the stem 29. magnetic material and is moves with the relay-magnetarmature and movable contact of the circuit-breaker.

In the form shown in Fig. .4: the hand-open ated motor-starting switch is provided with contacts for both forward and reverse running positions of the motor. The hand-lever is shown in full lines in a-forward-runningposition at 3 and in a reverse running position at 3". Intermediate between these positions at 3 is the initial or off position of the switch. All the other apparatus described in connection with the first form is equally applicable to this reversing form of switch. The relaymagnet 10 is directly connected between the leads in parallel with the armature-circuit, and the overload-contacts and push-buttons shown in the circuit of the magnet in the form first discussed are omitted for simplicity, as this figure is mainly introduced to show a modified form of connection between the hand-operated switch and circuit-breaker. In this form if the motor-starting switch is at a running position and the current through the relay-magnet is cut off the relay-magnet armature is permitted to fall to such an extent that on the restoration of the current to the relay-magnet the armature will not be attracted and again closes the circuit-breaker; but restoration of this starting-switch lever to its initial position brings the roller 27 into engagement with a modified form of connecting-arm 30 and lifts the arm. This in turn lifts a collar 31 on the stem 29, and thereby lifts the armature of the relay-magnet. The amount of lift is insufficient to close the circuit-breaker, but is merely sufficient to bring the armature into the intense part of the field of the relay-magnet, so that the armature will be lifted and the circuitbreaker automatically closed by the relay-magnet if current is flowing.

The improvements herein disclosed and claimed are in practice embodied in a handoperated switch embodying the features disclosed in the magnetic blow-out switch set forth in my United States Patent application filed January 9, 1904, Serial No. 188,358.

I do not claim herein the brake-load resist- This stem is of nonconnected to and I switches in combination with which it is illustrated, as the electrical features of the brakeload resistance are reserved for another application by me, Serial N 0. 205,514, filedApril 29, 1904.

hat I claim as new, and desire to secure by Letters Patent of the United States, is

1. The combination of an overload-magnet coil, a circuit-ln'eaker, a magnetic blow-out for the circuit-breaker, an overload-magnet, an armature which is operated by the overload-magnet coil, a common magnetic circuit for the overload-magnet, the overload-magnet armature and the magnetic blow-out, and means whereby the circuit-breaker is operated when the overload-magnet armature is operated, substantially as described.

2. The combination of an overload-magnet coil, a circuitbreaker, a magnet for operating the circuit-breaker, an operating-circuit for the magnet, a magnetic blow-out for the circuitbreaker, an overload-magnet, an armature which is operated by the overloadcoil, a common magnetic circuit for the overload-magnet, the overload-magnet armature and the magnetic blow-out, and contacts which are operated by the overload-magnet armature and are in the operating-circuit for the magnet foroperating the circuit-breaker, sul stantially as described.

3. The combination of a hand-operated motor-starting switch, an electrically-operated circuitbreaker, a motor-armature circuit containing the motor-starting switch and circuitbreaker in series, a brake-load resistance, a second motor-armature circuit through the brake-load resistance, contacts for this second motor-armature circuit, connections between these contacts and the circuit-breaker for preventing their concurrent closure, a relay-magnet for operating the circuit-breaker and the contacts for the second armature-circuit, a circuit for the relay-magnet, emergency devices for operating the circuit of the relay-magnet, and connections between the operated part of the motor-starting switch and one of the emergency devices for operating the relay-magnet in the opening position of the startingswitch, so as to close the second motor-armature circuit, substantially as described.

1. In a magnetic blow-out, the combination of a pair of iron-tipped contacts, means for opening and closing the contacts, and magnetic poles so positioned with respect to the contacts as to produce lines of force intersecting the spark-gap formed upon the separation of the contacts, said magnet-poles being out of electrical connection with the contacts, substantially as described.

5. In a magnetic blow-out, the combination of a pair of iron-tipped contacts, means for opening and closing the contacts, a magnet having a crosssection exceeding the crossance apart from the specific controllingl sectiontransverseto the linesofforcethrough the iron tips of the contacts, the magnet having its poles so positioned with respect to the contacts, as to produce lines of force intersecting with the spark-gap formed upon the separation of the contacts, substantially as described.

6. The combination of a hand-operated motor-starting switch, an electrically-operated circuit-breaker, a motor-armature circuit containing a motor-starting switch and a circuitbreaker in series, a relay-magnet for closing and holding the circuit-breaker in its closed position, a circuit for the magnet which is connected to the same leads as the armaturecircuit and is independent of the armaturecircuit, and automatic means for closing the circuit-breaker which is operative only when the starting-switch is in its initial position, substantially as described.

7. The combination of a hand-operated motor-starting switch, an electrically-operated circuit-breaker, a motor-armature circuit containing'the motor-starting switch and circuitbreaker in series, a relay-magnet for closing and holding the circuit-breaker in its closed position, a circuit for the magnet which is connected to the same leads as the armaturecircuit and is independent of the armaturecircuit, and mechanical means operated by the restoration of the starting-switch to its initial position for bringing the armature of the relay-magnet into the operative field of the magnet and thereby effecting the closure of the circuit-breaker, substantially as described.

8. The combination of a hand-operated motor-starting switch, an electrically-operated circuit-breaker, a motor-armature circuit containing a motor-starting switch and circuit breaker in series, a relay-magnet for closing and holding the circuit-breaker in its closed position, a circuit for the magnet which is connected to the same leads as the armaturecircuit, and is independent of the armaturecircuit emergency devices for interrupting the circuit of the relay-magnet, and automatic means for closing the circuit-breaker which is operative only when the starting-switch is in its initial position, substantially as described.

9. The combination of a hand-operated motor-starting switch, an electrically-operated circuit-breaker, a motor-armature circuit containining a motor-starting switch and circuitbreaker in series, a relay-magnet for closing and holding the circuit-breaker in its closed position, a circuit for the magnet which is connected to the same leads as the armaturecircuit and is independent of the armaturecircuit, an overload-magnet the coil of which is connected in the armature-circuit, contacts controlled by the overload-magnet in the circuit of the relay-magnet, and automatic means for closing the circuit-breaker which is operative only when the starting-switch is in its initial position, substantially as described.

10. The combination of a hand-operated motor-starting switch, an electrically-operated circuit-breaker, a motor-armature circuit containting a motor-starting switch and circuitbreaker in series, a relay-magnet for closing and holding the circuit-breaker in its closed position, a circuit for the magnet which is connected to the same leads as the armaturecircuit and is independent of the armaturecircuit, an overload-magnet the coil of which is connected in the armature-circuit, contacts controlled by the overload-magnet in the circuit of the relay-magnet, hand-operated devices for interrupting the circuit of the relaymagnet, and automatic means for closing the circuit-breaker which is operative only when the starting-switch is in its initial position, substantially as described.

Signed at New York city, New York, this 14th day of January, 1904c.

CHARLES E. CARPENTER. Witnesses:

THonAs EWING, J r., SAMUEL W. Emma.

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