US1665562A - Starter for electric mctors - Google Patents

Description

April 1o, 192s. 1,665,562

W. C. O BRIEN STARTER FOR ELECTRIC MOTORS Filed Nov. 4. 1924 El@ @Q Z9 .//Zm

Patented Apr. 10, 1928.

UNITED sTATEs A 1,665,562 PATENT OFFICE.

WILLIAM C. OBBIEN, F BALTIMORE, MARYLAND, ASSIGNOR, BY DIRECT AND MEBNE ASSIGNMENTS, TO CLINE ELECTRIC MANUFACTURING COMPANY, 0F CHICAGO, ILLINOIS, A. CORPORATION 0F ILLINOIS.

STARTER FOR ELECTRIC MCTORS.

Application led November 4, 1924. Serial No. 747,751.

This invention relates to distant controlled motor starters. The starter ofmy invention comprises a normally open main contacter, for opening and closing the arma- 5 ture circuit ef the motor, a magnet for moving said contacter te closed position, and a manually controlled switch for opening and closing the circuit to said magnet, in combination with one or more normally open auxiliary contacters, each adapted, when closed, te cut out a section ofthe starting resistance, means whereby said mainv centactor applies tension to the auxiliary contactors tending te close the latter, after the main contacter has closed the armature circuit, and means controlled by the current in the armature circuit for preventing said auxiliary contacters from c osing` while the current in the armature circuit is above a predetermined quantity. l

More specilically, the invention comprises a. main contacter which is normally held in open position by gravity and which is provided with a yielding contact member adapted to permit the body ef the contacter to move after the armature circuit has been closed, one or more auxiliary contacters, also normally held in open positions by gravity, magnets in the armature circuit for preventing the closure of said auxiliary contacters immediately upon the closure of the armature circuit, and s rings for closing said latter contacters, said main contacter adapted to apply tension te said springs, after said main contacter has closed the armature circuit. With this arrangement, a single magnet serves to close the main contacter and also to store energy in each of the auxiliary contacters, for closing the latter as 40 seen as released by their respective magnets..

In the accompanying drawing, Fig. 1 is a front elevation of the starter; Fi 2 is a side elevation of the same, lookin om left to ri ht in Fie'. 1;

ig. 3 is a simi ar side levation, one of the auxiliary contacters being removed;

Fig. 4 is a diagrammatic view showing the arrangement of the circuits; and

Fig. 5 is a side elevation of one of the auxiliary contacters.

Referring te Fig. 1 of the drawing, a represents a suitable panel or base plate oi insulating material upon which the starter is base a. Upon this bracket 4 is a pole iece 5,

which projects toward the pivoted p ate or 55 armature 1 and a magnet coil 6 surrounds this pole piece. When the magnet is energized, the plate or armature 1 rocks toward the pole piece, as indicated in dotted lines in Fig. 2, and when the magnet is de-energized, the plate rocks away from the pele piece, as shown in full lines in said ligure. A metal strip 7, preferably of non-magnetic material, such as copper, is secured to the plate or armature 1 by screws 8, and this strip projects upwardly beyond the coil 6 and is thence bent inwardly toward the base plate as shown at 7?, and a contact piece 7b is connected to the part 7"L by a pivot pin 7. This contact piece is normally pressed toward the base of the starter by a spring 9 which is arranged between the contact piece 7b and an arm er bracket 10 en the part 7. This springsurrounds a pin 11, which extends loosely through the bracket 10 and the contact piece 7", and this pin is headed so as to form. a` step for the part 7 and limit its movement away from the bracket 10. With the arrangement described, when the armature 1 is'attracted by the magnet 6, the con- .tact member 7" will rs't engage a stationary contact 12 and the continued .movement of the `armature will cause the contact member 7l to rock about lits pivotal point and compressthe' spring 9, as shown in dotted lines in Fig. 2. When'pthe current is cut off from the magnet, the armature will rock about the pivot pin 3, the expansion of the spring 9 tending to quicken this movement, and an arm 7d at the lower end of the strip 7 will engage the bracket 4 and limitthe outward rocking movement of the armature. The armature 1 of the main contacter has laterally projecting arms 1' and 1", which extend in front of the auxiliary contacters c and c. respectively. These latter contacters are alike in construction, each comprising a rocker 12, pivoted between its ends on a pivot pin 13 in a braclict 14 mounted on `the base.

y These rockers are preferably` of copper,.or

' adapted to engage a stationary contact 18.`

The lower end ofthe arm 12 ofthe contactor c extends over the pole of a magnet 19, arranged in the armature circuit of the-motor,' and the lower arm of the contactor c ex-/ tends over thepole of a magnet 20 also arranged in the armature circuit of the motor. These rockers carry adjustable iron bolts 25, which constitute armatures for the` magnets l19 and 20. @n the lower part ot the rocker 12 is secured a Hat spring 21 which projects upwardly in front ot the bodyjof the rocker, and the tree end ot this springl extends .beneath a stop 22, .tormed by an arm which projects outwardly trom the body ot the .rocker near its contact end, as'shown. A

similar spring, 21a., and a stop 22a are shown upon the contacter c.

-Upon the arms 1Ln and 1b of the main contactor are arranged pins 23 and 24 which are adapted to bear upon the'l fiat springs 21 and 21a, respectively, after the contact member 7b of the main contactor has engaged lthe stationary contact 12 and closed the armature circuit. It is important that these pins shall not engage the springs until alter the armature circuit'has been closed. The closure of the armature circuit causes the magnets- 19 and 20 to become energized, as will be further explained, and these magnets hold f the auxiliary contactors in open positions as llong as the armature current is above a predetermined quantity. After the'circuit has been closed, thepins 23 and 24, which move with the main contactor, bear on the springs 21' and 21a and kpress the latter to the ydotted line position shown in Fig. 2, thus storing energyin the springs, and as the. magnets I so.

19 and 20 of the auxiliary contactors weaken, during the acceleration of the motor, these release said contactors in succession and the contactors are immediatel moved to their closed positions by the tension of the springs. When the magnet of the main contactor is (le-energized, the latter moves to the open position and thus the pins on said contactor are moved out oE engagement with the springson the auxiliary contactors yand the latter move to open positions by gravity.

Referring to the diagram Fig. 4, l.; and

L' indicate the supply wires of an electric circuit and m indicates a direct current electric motor com rising the armature 26 and eld winding 2 Current from the supply wire L extends through conductor 28 to the coils of a suitable blow-out magnet 29, the poles-of which are arranged adjacent the stationary contact 12, and from the coil of the blow-out magnet the circuit proceeds by L of the sup ly circuit.

conductor 30 to said contact. From the contact 12, a circuit for thev magnet of the main conductor 32 to a manually operable switch 33, thence through conductor 34 to the side By closing the switch 33, it wi l be evident that the magnet '6 will move the main contactor to the closed position and this will bring the member 7*? of -said contacter into engagement with the stationary contact 12. `The field winding 27 of the motor is connected by conductor 35 to the contactor b and .when the latter is in closed position, current will flow from Jthe contact 12 through said bcontactor to the held 27, thence by conductor 36 to the supply wire li. The main contacter is electrically magnet 19, thence through conductor 41 to.

the coil of magnet 20, thence through resistance 42 and conductor 43 to conductor 44,

' thence through the armature of the motor to the supply Wire L. As the magnets 19 and 20 will be energized the moment the flexible -contact memberf7? touches the contact 12,

thesemagnets will hold ,the auxiliary cone tactors in open p0sition. Immediately after theclosure of the armature' circuit, the final movement of the main contactor will cause vpressure vto'be'applied to the springs on'vthe auxiliary contactors, tending to `close 'the los latter. Asthe motor accelerates, the current f y in the armaturen circuit will decrease and when the volume of this current has fallen to a predetermined quantity, the magnet 19. will be so weakened that the tensionapplied to the spring 21 will cause the contactor-c tactoiI will engageV the stationary Contact 16. When tlns occurs, the auxiliary contacter c will short circuit the resistance section 40,

to rock away from said magnetand said con- L the coil of magnet 19 and apart of the coil of ma net 2() through a circuit which extends trom the side L ofthe supply circuit,

through the coil of the hlow-out magnet and the main contacter and conductor 37 to the auxiliary contactorc and contact 16, thence through conductor 45. to an intermediate part of the coil 20, thence through a part of said coil and the resistance 42 and conductors 43 and 44 to the armature and thence to the side L of the supply circuit. Upon the cutting out of section 40 of the resistance and the magnet windings, the current in the armature circuit will increase and then decrease as the motor accelerates further, and when the current then falls to a predeterminedamount the magnet 2O will be Weakened suiiiciently to release the auxiliary contactor c and the spring 21 will then immediately cause the said contactor to rock to closed position. When this contacter closes, the remaining section of the coil 20 and the resistance section 42 will be shortcircuited, the current then liowing directly from the main contactor through conductor 38 to the auxiliary contactor c', thence to contact 17 and through conductors 45 and 44 to thel armature. -The motor Will then run with all of the resistance cut out. When it is desired to stop the motor, it is `only necessary to open the switch 33 and this Will cause the magnet of the main cont'actor to be de-energized and the pressure of the main contacter against the springs of the auxiliary contactors will then be released and the several contactors will rock by gravity to their open positions, reavcy for the next starting operation.

hat I claim is:

1. In a starter for electric motors, the com* bination of normally open, main and auxiliary contactors, a normally inoperative spring for closing said auxiliary contactor, a magnet for opposing s aid spring, and parts mounted on said main contactor for successively closing the circuit of said magnet and plac1ng said spring in operative condition, 35

substantially as described.

2. In a starter for electric motors, the combination of normally open, main and auxiliary, pivoted contactors, a normally inoperative leaf spring mounted on said pivoted auxiliary contactor for closing the latter and a magnet for opposing the operation of said spring, said main contactor having a yielding contact and a rigid abutment arranged-to successively close the circuit of said magnet and engage and tension said leaf spring, substantially as described.

3. A starter for electric motors comprising a normally open main contactor adapted to closeand open the armature circult, a magnet for moving said contactor to closed position, a switch controlling the circuit of said magnet, a. normally open auxiliary contactor, a magnet in the armature circuit of the motor adapted to prevent the closure of the latter contactor after the armature cir-v cuit has been closed and until the startin current falls to a predetermined value, an

a spring carried by the auxiliary contactor, said main contactor, after it has closed the armature circuit, being adapted toengage said spring and apply tension to the same tending to close the auxiliary contactor.

4. A starter for electric motors comprising' a pivotally supported main contactor,

normally in open position and adapted to close the armature circuit, a magnet for moving said contactor to closed position,a switch controlling the circuit of said magnet, an auxiliary contactor pivotally supported adjacent the main contacter and normally in open position, a magnet in the arm'ature circuit for holding ,the auxiliaryr contactor in open position until the startin current falls to a predetermined value, an

a spring carried by the auxiliary contactor, said main contactor, after it has closed the varmature circuit, being adapted to engage said springand apply tension to the same tending to close the auxiliary contactor.

5. A starter for electric motors comprising a pivotally supported main contactor having a yieldingly mounted contact member, a sta-V tact-member has engaged said stationary contact, for applying tension to the auxiliary contactor tending to close the same.

In testimony whereof I hereunto afiix my signature.

WILLIAM C. OBRIEN.

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