US1097256A - Circuit-breaker. - Google Patents

Description

E. J. MURPHY.

CIRCUIT BREAKER. APPLICATION I'ILED' FEB. 2, 1912.

1,097,256, Patented May 19, 1914.

Fig. I."

WITNESS '5': INYENTDH EDWIN JMUHPHY,

H25 ATTUBNE'Y.

UNITED sTArEs nnwnw. MURPHY, or SCHENEC'IADY,

LPATENT'OFFICE, I

NEW YOBK, ASSIGNOB 130 GENERAL ELECTRIC COMPANY, A COB'FQILTION OF NEW YORK.

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Patented May 19, 1914.

To all whom it may concern:

Be it known that I, EDWIN J. MURPHLB citizen of the United States, residing at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Im royements in .Circuit- Breakers, of which t e following is a specification. j

This invention relates to devices for $01 trolling electric circuits andh-as forits object the provision of means whereby an electric circuit may be opened and closed in a reliable, safe and eflicient manner.

My invention relates more speclfically to devices for automatically opening an electric circuit upon the'occurrence of predetermined circuit conditions such as an overload crabnorm'al decrease of voltage, means bein provided whereby the circuit 'aiter once eing opened cannot be a ain closed by the operator until after the clrcuithas been placed in a protected condition. v In one aspect myinvention comprises a remote contro circuitbre'aker so arranged that upon a opening of the circuit, the operator inlorder to close it must actuate a switch mechanism so that the parts of the circuit breaker are placed in a condition to be closed and in the other position of the switch mech anism the circuit breaker will close. This arran ement' is of extreme importance in the contrfi of electric motors where aresistance is inserted in the motor circuit during start ing' and is gradually out o t of circuit as the" motor is brought up to r ning speed. By my arrangement the'opera'tor first moves the switch to a protective position and then.

moves it to the position in which the circuit breaker closes. Furthermore, by the use of my invention it is impossible for the operator to hold the circuit breaker closed while the overload or other abnormal circuit condition which caused the circuit breaker to open continues. c V In carrying out my invention I employ an electro-magnetic contactor for closing the circuit and an electro-magnetic relay for controlling the energizing circuit of the contactor. This relay is so constructed and arranged that when the control switch is moved to one position, the ectuati coil of the contactor is connected to one si e of the line so that when the switch is moved to the other position the actuating coil of the con- 55 motor is energized to close the contactor.

To close thle'circutit breaker, therefore, the" r switch must firstbe moved to one'position to cause the. relay tofmove to the corresponding pos tlon and mustthen be moved to .the opposlte position to"--cause the relay to assume the corresponding position and close the con tactor. Upon the occurrence of an abnormal clrcu t condition. the: circuit' breaker v will open andthe -o. er'a'tor must make this double movement 0 the switch mechanism in order to-close it. Furthermore, while the relay s closed, -the actuating-flcoilof the relay is talnng no current.

. 1 111 the accompanying invention, Figure 1 1s a diagram- Inat c representation of one form of my inventlon;v Fig. 2 represents a slightly modified form; and Fig. 3 illustrates my invention applied to a motor control system;

Referring first to Fig. 1, 0 represents a oontactor and R a relay, which taken together constitute the circuit breaker. The contactor consists of a winding 10 and a core llarranged to close the switch arm 12 on its contact to close the mainline L L. This relay consists of two switches, one being the mainswitcharm 13 pivoted at 14, while the other "is an auxiliary switch arm 15 pivoted at 1.6. The switch arm 13 is operated. by. a rod'17 having at its lower end a core 18 co op'eratingwith a winding 19. This core '18 is so arranged as to hold the switch in an open position asshown in the drawing by its weight when the winding 19 is deenergized. The'switch arm 15 is of the bell crank'lever form and has a long tail piece projectin over toward the switch arm 13. On the en of this projection are two shoulders 20 and 2.1, ooiiperating with a 111 22 on the arm 13.

The construction is such t at when the main switch arm 13 is closed, the tail piece will drop down until the shoulder 20 engages the 3 lug 22, thereby holding the switch 13 closed. This, of course, presupposes that the switch 15 is not held in its closed position from any cause. In a'similar manner, when switch 13 is in the open position and the switch 15 is closed, the latter is held closed by the engagement of the lug 22with theshoulder 21, as shown in the drawing. Auxiliary switch 105 15 is moved to closed position-by. t overload coil 23 provided with a core 24 which rises when overload occurs and strikes the tail of the switch 15"and moves it to closed drawings illustratposition. A control switch25 is pivoted so Q oeneae close the circuit breaker, the switch 25 is moved so as to engage the contact 27. This energizes the actuating coil 19 through the switch 15 and causes the main switch 13 to close. As soon as this closes, the'auxiliary switch 15 is released and the tail 17 drops and locks the switch 13 in the closed position. The switch 25 must now be moved back into engagement with contact 26 so as to energize the coil 10 and close the contactor C. It now an overload should occur upon the line, the core 24 will lift so as to lift thetail and close the auxiliary switch 15 and allow the main switch 13 to open. To close the contactor, the operator will move the switch 25 into engagement with the contact 27, as before. This, will close the auxiliary switch 13 and a movement of the switch over to contact 26 will close the contactor. From this'arrangement it will be seen that the operator must always move the controlling switch to two positions in order to close the contactor. Thismakes it impossible for him to hold the contactor closed while there is an abnormal condition on the line, since the circuit will always be opened 7 independently of the operator. As long as there is an overload on the line the switch 13 will not latch closed. The switch 13 can be closed and held closed by keeping the switch 25 on contact 27 but as soon as the switch is moved over to 26 to close, the overload device will operate to. open the switch 13. It will therefore be impossible to hold the contactor closed while thereis anoverload'. lf, however, it is desired to open the contactor at any time, the switch 25 may be moved off of contact 26 so that by moving the switch 25 back and forth between contacts 26 and 27,.the contactor can be opened and closed. It will be noted that the operating coil of the relay only takes current for an instant so that when it is once closed it does not consume current, Moreover, a very heavy operating current may be used since the instantaneous current, although heavy enough to burn out the coil if left on continuously or even for a relativelyshort time, will do no harm.

lln Fig. 2., l have shown a modified arrangement for providing for the condition of failure of voltage. The arrangement diftiers fronrthat shown in Fig. 1 merely in that the resistance S is connected in series with the windinglO and a normally open switch 28 is provided for short circuiting the resistance. In order to close the contactor in this case, the switch 29, which is drawing, must be pressed downward so as to close the circuit of the winding 19. This will close the switch 13 as before. When the switch 29 is released and the switch 28 is closed, the contactor will close through the energization of the winding 10 as before. The switch 28 may then be released. The releasing of the switch 28 places the resistance S in series with the winding 10 so that there will be sutiicient current to hold the contactor C closed but not sufiicient current to close it. It, therefore, the voltage on the line should fail and the contactor C should open while the switch 13 is closed, a return of voltage to the line will not cause the contactor C to close, but the operator must close the switch 28 to short circuit the resistance S before the contactor will close. Otherwise the circuit breaker operates in the same manner as that shown in Fig. 1.

In Fig. 3, l have shown my circuit breaker as it is used in a motor circuit. In this case the controller T brings the motor M up to starting speed by gradually cutting the resistance R out of the armature circuit and the cont-actor C closes the motor circuit. In this case it will be seen that the controller must be brought to the first starting position shown in the drawing, in which all of the resistance R is in the motor circuit before the contactor can be closed. Tn this first starting position the coil 19 will be energized from the line L through the se ments 30, 31 and 32, conductor 33, coil 19., switch 15, and back to line L. This moves the relay to the position shown in the drawing, and then by moving the controller to the next position the segment 31 engages with its corresponding contact on the, controller, the winding 19 will be denergized and the winding'ofthe contactor energized through the switch 13 as before. This arrangement is no ditlerent from that shown in Fig. 1, but merely shows one practical application or" my invention.

T have not described the details of construction of my relay nor have I claimed the same herein, since the construction of this relay forms the subject matter of my pending application, Serial No. 67 1,5979, filed Feb. 2, 1912.

It should be understood, of course, that while I have shown my invention as embodied in concrete forms "for purposes of illustration, I do not limit my invention thereto, since various modifications thereof will suggest themselves tothose skilled in the art without departing from the spirit of my in vention, the scope of which is set forth in. the annexed claims.

lVhat I claim as new, and desire to secure a by Letters Patent of the United States, is 1. The combination with an electromagnetic contactor, of a two-position relay provided with an overload coil for moving it to so I one position, and an actuating coil for moving it to the opposite position, switch contacts closed in one position for controlling the actuating coil and in the other for con-' Q switch is moved to one position and the contactor circuit completed through said contacts and the switch when the latter is moved to the other position.

3. The combination with an electromagnetic contactor, of a two-position relay controlling the same comprising an actuating coil for moving it to one position, an overload coil for moving it to the opposite position and two switches respectively connected to the energizing coil of the contactor and the actuating coil of the relay, one of said switches being closed and the other .opened in each position, and a two-position switch for completing the circuit of either the contactor or the actuating coil of the relay through its corresponding relay switch.

4. The combination with an electromagnetic contactor, of a relay comprising an actuating coil, an overload device, contacts for controlling the energizing circuit of the contactorarranged to be closed by the energization of the said actuating coil, contacts for controlling the actuating coil arranged to be closed by the operation of the overload device, and a twoposition switch arranged to complete the circuit through the actuating coil and its relay contacts in one position and in the other position to complete a circuit through the energizing coil of the contactor and its relay contacts.

5. The combination with an electromagnetic contactor, of a relay switch biased to open position, an actuating coil for closing said switch, a latch for holding the switch in closed position, a two position switch,

vand connections whereby said latter switch in one position completes the circuit of the actuating coil and in the other position closes the energizing circuit 4 of the contactor through the relay switch contacts.

6.- The combination with an electromagnetic contactor, of a relay switch biased to open position, an actuating coil for closingv said switch, a latch. for holding the switch in closed position, a second relay switch, means whereby sald latter switch is closed and the latch tripped to open the first switch upon the occurrence of abnormal circuit conditions, a two position switch and connections whereby said switch in one posi-: tion energizes the actuating coil through the switch contacts of the second relay switch and in the other position closes the energizing circuit of the contactor through the first relay switch contacts.

7 The combination with an electromag netic contactor, of a two-position'relay provided with an overload coil for moving it to one position, an actuating coil for moving it to the opposite position, a switch contact closed in the position to which it is moved by the overload coil for controlling the actuating coil, switch contacts closed in the position to which it is moved by the actuating coil for controllingthe energizing coil of the cont-actor, and a switch having corresponding positions for completing the circuit through either of said coils in series with the contacts which control the coil.

8. The combination with an electromagnetic contactor, of an electromagnetically actuated relay having contacts controlling the energizing circuit of the contactor, a two-position switch, and connect-ions whereby the relay is actuated to close its contacts in one position of the switch and the windof the contactor energized through said con tacts in the other position of the switch, a holding resistance in the energizing circuit of the-contactor and a switch for short circuiting said resistance. ,7

9. The combination wit-h an electromagnetic contactor, of a relay having switch contacts for controlling said contactor, an

overload coil for opening said contacts, a switch having two operative positions, connections whereby the actuating coil is energized to close the contacts when the switch is moved to one position and the contactor circuit completed through said contacts and the switch when the latter is moved to the other position, a holding resistance in the energizing circuit of the contactor, and a switch for short circuiting said resistance. In witness whereof, I have hereunto set my hand. this first day of February, 1912.

HELEN ORFORD.

actuating coil for closing said contacts, an

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