US1310269A - Electromagnetic contactor - Google Patents

Description

n. wmH.

ELECTROMAGNETIC CONTACTUR.

APPLICATION FILED JUNE 28. 1916.

Patented July 15, 1919.

A TT ORNE Y.

THB coLUMBlA PLANonRAPM Cu., WASHlNu'roN. n. c.

UNITED sTATEs PATENT eEEIeE.

REUBEN I. WRIGHT, OF WICKLIFFE-ON-THE-LAKE, OHIO, ASSIGNOR, BY MESNE ASSIGNMENTS, TO THE ELECTRIC CONTROLLER 6c MANUFACTURING COMPANY,

A CORPORATION OF OHIO.

ELECTROMAGNETIC CONTACTOR.

Specification of Letters Patent. l

Patented July 15, 1919.

Application led .T une 28, 1916. Serial No. 106,383.

To all whom it may concern:

Be it known that I, REUHEN I. WRIGHT, a citizen of the United States, residing at Wicklileon-the-Lake, in the county of Cuyahoga and State of Ohio, have invented new and useful Improvements in Electromagnetic Contactors, of which the following is a specification.

This invention relates to electro-magnetic contactors, and particularly te electro-magnetic centactors used in motor-control systems.

In some types of motor-control systems it is the common practice to employ shuntwound electro-magnetic contactors to successively cut out of the motor circuit the motor start-in resistance sections, and to employ also cidre-magnetic relays to govern the closure of the contactors. Various arrangements have been devised for associating the relays and contactors together se that the closure of a contacter actuates its associated relay, and the subsequent operation of the relay controls the succeeding contacter, and so on. Various attempts have been made also to associate the relay and the contacter in a structure so that the relay, when the contacter is open, will be held open mechanically by certain members of the contacter, such, for example, as the movable contact arm, and also so that the relay will be held open electro-magnetically after the closure of the contacter, as, for example, by the motor current Howin through the contacts of the contacter, w ien this current is above a predetermined value. But these structural arrangements have had the disadvantage that, during the time in which the contacter is closing, that is, after the contacter has ceased to hold the rela open mechanically, and before the relay 1s held open magnetically, there is a period ci time in which the relay is free to close and may close accidentally and result in an abnormal operation of the system.

The contactors when employed in this manner are usually provided with arc-rupturing or blowout magnets, in order that the contactors ma be opened in a practicable manner to reinsert the sections of motorstarting resistance. It has heretofore been the common practice to employ structurally independent relays and contactors, resulting in inexpensive and cumbersome aaparatus.

One of the principal objects o this invention is to simplify the apparatus used in motor-control systems by providing a single electro-magnetic structure embodying the contacter proper, the blowout magnet, and the relay, and employing the winding of the relay as the energizing winding of the blowout magnet.

Another object of this invention is to pre` vide an electro-magnetic contacter and relay in a single structure in which the relay contacts are held open mechanically by some part of the contacter when the contacts of the contacter are open, and held open electro-magnetically by motor current if above a predetermined value, after the contactor contacts have closed, the relay being prevented frem moving toward the closed position during the whole time that the contacts of the contacter are moving from open to closed position.

Another object of this invention is to provide an electro-magnetic unit contacter which may be used as one of a train of like contactors in a motor-control system, and have main contacts for controlling a section of starting resistance and auiiiliary contacts for governing the closure of a succeeding switch, the main and auXiliary contacts being associated together in the contacter structure in such manner that, the auxiliary contacts will normally tend to close, but will be held open mechanically until the main contacts are closed, and will be held open electro-magnetically by motor current above a predetermined value.

Other objects will be apparent from the following description.

In the accompanying drawing, Figure l is a side elevation of my invention, partly in cross section, and with parte broken away; Fig 2, a partial front elevation of the invention with the coil 43 omitted; and Fig. 3, a diagram of connections showing a motor-control system embodying my invention.

On the drawing, l0 represents the slate or other insulating base, upon which the parts of the structure are mounted. The L-shapcd magnet7 frame 11, havingl the coro 1,12, Wliich supports "the winding 1.' is mounted on the slate 1() by the stud 14 and the nu=t 15. The stud 14 also serves as a connection point for a n electric circuit to be described later.

Pivoted to thc frame 11 at 1G is the movable magnetic contacter arm 17, having` the pole face 18 magnetically cri-acting with the adjacent end of the core 12. The.arm 17, normally occupies theopen position shown, the stop 19 resting upon the frame 1,1. The ribbon connector 20, secured tothe frame 11 at 21 and to the arm 17 at 22, fqfm a 1 electrical shunt about the pivot 16. "Qn tje' ilpper end of the arm 17 is the contactQ.

The iron bracket Q4 is mounted on he slate by the bolt 25 and the nut Q6, and ias the web 27 and the flange QS. Pivoted to the web '27 at 29 is the relatively stationary contactor-arm 30, on the upper 'end of which the Contact 31 is secured. The spring 32 extends from the. arm 30 to the flange 28, and normall,r holds the arm 30 agai'nstthe stop 33 r on the bottom of the flzmaqfeV 28.

The iron 'bracket 24 has un'upwardly and fori-vardly extending wing 34, forming at 35 one of a pair of arc-rupturin orb-lower@ magnetic poles. The other'` po e 36 'of' the pair is provided by the' dowiiiyardly' and forwardly exten'ding wing 37' olf' another bracket 38, mounted on the slate, by the 39 and the nut 4.0. They op site telles 'olf the blowout magnetic `poles and 3C? lie in parallel planes, the contacts Q3 and 31 beingr between the poles. Each pleis provided with an arc-shield 41 which stands between the pole and the contacts.

Extending from the bracket 38 to the bracket 24, with its axis il'ertical, is a noninagnetie s ool 42, on which 1s wound'a blowout coil 43, the terminals 44 of which are secured to t efslates theA nuts 46 and 47. The terminal 14 elJso serves' as a connection point for an electric circuit to be described leben A coiinll" 4.8, connects at one end'with tlie" `ter1niral 49",' 'and passingthrough e hole 4Q ln, thes'lat con# nects at the other end with 'the erin" Q, ber in secured thereto the screw V. he parte thus fer described'constitut@ the contacter proper of the unit 's "ncture, `When the Winding 13 is energized he ednnections 'thereto not being` fluir w l flow in the core 12, the ,freine` l, the 1,5 and 4the air g'p between the p01@ 121@ lffend the pole 12, "whereby the arm'K y drawn toward the` core bring g" the contact 23 into engagement' Withft e'contact 31. If," connections are Inade from an electric Circuit t@ the Suid 14 ,anat e terni, nal 44, current will flow' inthe ollowin` circuit: from the stud 14, through the frame 1l, the ribbon connector 20,'the arm 17, the

contacts 23 and 31, the arm 30, the ribbon connector 48', the terminal 45, and thc blowout coil 43 to the terminal 44. After the contacts 23 and 31 meet, the spring 32 will be compressed, and the relatively stationary arm iwill `be rotated counter clockwise into the position shown in dotted lines at 51. Tlul spring 32 then serves to hold the contacts 31I and infirm engagement. The current flowing through the blowout coil 43 genera ates lux which flows say, upwardly through the core of the spool 42 into the bracket 38. and tlincb totli iiiing 37 and the pole 36, Iand thence across the space between the shields 41 into the pole 35, the fingy 34, und the bracket '24. When it is desired to break the circuit which is closed at the coiitacl's E23 and 31, the Winding 13 dencrc'ized und the action of gravity on the arm 1l, in connection with the action ol the spring' causes the contacts 23 and 31 to bc opened, whereupon the arc which forms between theri will beblown out by the magnetic flux just described, flowing between the polesl Sli and 35.

The bloWo it coil 43 is made to serve as the actuating coi of a relay, the partsof which wil'lno'yv be described. The stationary adjustable' polepiec'e 52 is threaded into thc bracket', end'exten s into the core of the spool`42, and the locknut' 53 is provided to secure it in any adjusted position. The pliiiiger 54 Ais arranged to move vertically in tlfecole1 of `the spool 42. The lower eiid of the plunger, which tenminates in the pin 56,)is separated from thc main body Si of the plung'er by an insulator 57. The body portion ofthe insuator 57 is of greater diameter than theA p unger 54 and the core of 'the spdol 42, so that the insulator 5T, besides insulating the t'wo parts of the plunger x'rein other, provides a 'stop which. by engaging the 1lower end of the spoel l1-2, serves tolirni the upwardmovcment ol tho plunger 5`4.` lo thefupper end of the plunger"54 is Seculd a rr'i'ofn-Inegnetic stem 5S, which passes upwardly through a central bore in the pole 52, and carries on its upper end the Contact isk 59. The plunger 54, the stein 58., and he disk 59 are Asupported normlly by the pin 56 festin on the arm 30" y adjustment of the poe 52 the air gap G3 betwenlthe lower end thereof and the upperend o the plunger 54, may be lengthened "r shortened. When tl'ie blowout coil 43 is energized, the flux therefrom in this airgap ten s to 'pull the plung'l" :54 upward'ly,`the'movement 'being lmited by the insulator 57. bunte' on the slate by t e` nuts are the two studs 61, carrying the setipilar.. fr ey' ontacts 62, adapted to be engagel'hy t e @Ohtt disk 59. The studs 'lelso serve as connection points for control circuit connections to be described.

nza-10,2139y The operation of the relay will now be described. When the contacter contacts 23 and 31 are open, and the arm 30 is in its normal position, the p-in 56 rests thereupon, and the contact disk 59 is held upwardly out oi engagement with the rel-ay contacts 62. If, when the contact 23 is first moved into engagement with the contact 31, thus closing the main circuit, as has |been described, if the current flowing therethrough, and hence through the coil 43, is above a predetermined value, depending upon the adjustment of the adjustable pole 52, the plunger 54 will be held upwardly by the flux from the blowout coil 43; and when the contacts 23 and 3l have moved to their full closed position, and the arm 30 occupies the position shown in dotted lines at 5l, the plunger 54 will not fall until the current through the contacts 3l and 23, and hence in the coil 43, falls to the predetermined value, the flux from the blowout coil then being insufficient to hold the plunger 54 upwardly, whereupon it will bring the disk 59 down upon the relay contacts 62.

It; is apparent that the plunger 54 and the pole 52 serve not only as parts of the relay, but as a part of the magnetic circuit of the blowout magnet. If the contacts 31 and 23 open before the plunger 54 has fallen, the air gap 63 will be of minimum length, and the reluctance of the magnetic circult of the magnetic blowout will be at a minimum, and the arc will be blown out effectively. On the other hand, if the plunger 54 has fallen before the contacts 31 and 23 open, it will be raised again by the initial opening movement of the arm 30 acting on the pin 56 before lthecontacts 3l and 23 have actually separated sufliciently to draw an arc, and hence in this case also the air gap 63 will be at a minimum and' will not introduce reluctance in the magnetic circuit of the blowout magnet.

One of the uses lto which my invention may be putin connection with motor control systems, will n'ow be described.

Referring to Fig. 3, A represents the armature and F the shunt field of the motor, R1 and R2 the sections of the starting resistance, H a master controller, S1 and S2 diagrammatic representations of the unit structure shown in Fig. 1, and S3 a shuntwound magnetic contactor of any well known and suitable form. Each of 'the contactors S1, S2, and Sa has the main contacts 31 and 23, the actuating winding 13, the blo-wout coil 43, ther contactor arms 17 and 30; and the contactors S1 and S2 have also the relay plunger 54, the contact disk 59, and the relay contacts 62.

Upon -moving the master controller H to the full-on position, so that the arm h is in engagement with the three contacts k1, k2,

ylia, the winding 13 of the contacter S1 is energized, the control current flowing from "the positive main 64, through thel arm h, the Contact 11.1, the winding 13, and the wire to the negative main 67. The contacts 31 and 23 are closed by the coil 13, and motor current Hows from the positive main 64 through the arm 17 of the contactor S1, the contacts 23 and 31, the connector 48, the blowout coil 43, the resistance sections R1 and R2, and the motor armature A to the negative main 67. The motor starts, and the current being above the predetermined value for which the relay of the contactol S1 is adjusted, the plunger 54 of this relay is held upwardly and the contacts 62 of the relay remain open. After the starting current falls to the predetermined value, the plunger 54 falls, and the disk 59 closes the contacts of the relay, thereby admitting current t0 the winding 13 of the contactor S2, current thereto flowing from the main 64, through the arm It, the master contact k2, the contacts 62 of the relay on the contactor S1, the winding 13 of the contactor S2, and the wire 65 to the main 67. The contacts 31 and 23 of the contacter S2 now close, shortcircuiting the resistance section R1 and holding the relay contacts of the contacter S2 open. Subsequently, when the motor current falls to the predetermined value for which the relay of the cont-actor S2 is adjusted, the relay contacts of the contacter S close as was the case with the contacter S1, and admit current to the winding 13 of the contactor S3. The contacts 31 and 23 of the contacter S3 close, shortcircuiting the resistance section R2, whereupon the motor is brought up to full speed.

While the control system as described will operate automatically to bring the motor up to full speed, when the master handle It is thrown to the full-on position, it is apparent that each contactor S1, S2, or S3, can be prevented from closing by holding the master arm h out of engagement with the corresponding master contacts h1, h2, or he, respectively. Likewise, after the closure of any contacter S1, S2, or S3, it may be caused to open and reinsert the starting resistance, or open the motor circuit, as the case may be, by moving the master arm k out of engagement with the corresponding master` contact, and when one of the contactors S1, S2, or S3 is thus opened, the are caused thereby on the contacts 31 and 23 will be blown out by the flux generated by the coil 43, as has been described.

My invention is not limited lto the exact form of the various parts of the unit structure or device in Figs. 1 and 2, nor to the particular diagram of connections illustrated in Fig. 3, by which the device may be applied `to motor-control systems, since the mechanically restrained from movement by y main contacts when the Current in the vindthe carrying member, and a Winding foning is above a prefletel'nned value only. trollin the auxiliary contact, energized Signed at Cleveland, Ohio, this 24th day throng the main contacts and adapted to of J une, 1916.

5 magnetically restrain the auxiliary contact from movement after the engagement of the REUBEN I. WRIGHT.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C.

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