US860104A - Automatic starter for electric motors. - Google Patents

Description

No; 860,104. PATENTED JULY 16, 1907.

V W. 0. OBRIEN.

AUTOMATIC STARTER FOR ELECTRIC MOTORS. APPLICIATION FILED APR, 19,1905.

4 SHEETS-SHEET 1.

PATENTED JULY 16, 1907.

W. C. OBR IEN.

AUTOMATIC STARTER FOR ELECTRIC MOTORS.

APPLICATION FILED APR,I9,1905.

4 SHEETS-SHEET 2.

a J 6 /FF 7% 4 A A 'l QEEI EQ IJEFIE I attozwzw PATENTED JULY 16, 1907.

W. G. OBRIEN. AUTOMATIC STARTER FOR ELECTRIC MOTORS.

APPLIOATION FILED APR,19, 1905.

4 SHEETS-SHEET 3.

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, 8 through binding posts 9 and 1G to toe WILLIAM C. OPRHEN, OF 13 COMPANY, OF E L No. sis-0,104.

To all whom it may concern:

Be it known that i, WiLmAM O. QBRIEX, s. citizen of the United States, residing Belt f1 of Maryland, have invented cei Improvements in Automatic Starters Motors, of which the following is specifice. This invention compiises improveni rustic starters for electric motors, the d vantages of which will be'pointe-d out specification, taken in connection with is ing drawing, in which,

Figure 1 is sfront elevation of he p section, the parts being shown in their norms and the circuits being shown diegreminsti 2 is a section through the base plate of the stc. line 2 2 of Fig. 1, the Contact fingers beingond view and in their raised positions. elevation 02 the starter, partly in sectiot inteoosing lever in full lines at the solenoid circuit is about to be into riipted, lines, in the position which it occupies whi. is running. Fig.4 is a section through the on the line 4-4 oi Fig. 3, show pressed against the contest-go 7 starting resistance the fingers to Fig. 5 is 2. side elevation of posing lever portly raised.-- or the same, showing also in li lgli rang'ement of the solenoid circuit, t tion on the line 77 of Figl it, Elli)? lever and the circuit closer op Referring to the drawing, A indi B the automatic sts ter; C in es on electric motor, and l electric circuit which are connect the switch. One terminal 3 of the s by e.- wire 4, through hinding. minel of the field f and armature r; Another terminal '7 of the toll oi the field f, and the srLstnre c tbmugh'e. wire 8 leading from the erinstuz post '11, thence to the thence to the stzirting resistance it, r sistsn ce through a blow-out magnet Iii to I .Contsct pieces or buttons 13, nected to the resistance R, as shown cents-ct buttons preferably consist of cvii of carbon 6 arranged within cups wk upon studs a, the latter extending plate b 01" the starting device and the resistance, as shown. The costs-ct 3?, at the ends of the serl es of cents.

metal a; the edjac t cont'ic normally pressed upward from the front plate 1 19,1905. Serial No. 2565553- springs 18, as shown in 2.

Upon a rock shaft 19, which 20 having srings 20", its ends, are or series of lo sely mounted contact fingers 13*, T.

16 adapted to bear upon the cons st-s13,

resoectivcly, when these fingers are pros downward, shown in Fig and 15 are pro journslcd in :1 bracket 1. inc Contact lingers l1 lateral projections 12 and 17 adapted 'to engage the metal contact pieces 12 and 12 respectively, when the fingers are dc- L e stiles.

Wit

'tno srins 2.1, which we r ock shaft and the contact in ch are loosely inoun Stop pins 23: arranged upon the outer ends ction, pressure IS applied to the orcs them against the contact 1 rse direction, thus drawing horn he contact pieces d upon the rock sit is moved in. ing the stops 23 c from the cont: :t ion the rock shalt moved shaft. ai'hcu the when the main switch opened word and causes the root: shaft the con- 12 to 17 inl and 2. The circuit ior and 3 extends from tcrinie toe-in switch throw :1 wire Q8 to one terminal OL we '216 Contact fingers at port 20, and the star;

sistance R is then shunted; when the contact fingers are all raised as shown in Fig. 2, the armature circuit is interrupted between the contact pieces or buttons 12 and 1s; 1 V

I provide means for permitting the. contact fingers 13 to 16 inclusive to be pressed successively against the contact pieces 12 to 17 inclusive, in order to cut the starting resistance gradually out of the armature circuit. When the contact finger or member 13'is pressed downward, it first engages the spring pressed contact 13 having a carbon block and forces the latter downward until the lateral projection 12 engages the 'metal contact piece 12. The armature circuit is then completed through the contact arm 13 from the contact piece 12, to the contact piece 13, and thence through the starting resistance R. v The contact finger or member 14 is then caused to engage the contact piece 14 thus cutting out part of the starting resistance and the contact members 15 and 16 successively engage the contact pieces 15 and 16, thus further reducing the resistance in the armature circuit. The spring pressed contact piece'16 containing a carbon block is depressed by the member 16 until the laterally projecting arm 17 of the latter engages the metal contact piece 17, thus cutting out the resistance between the contact pieces 16 and 17. A complete metal circuit is then formed in shunt to the starting resistance from the metal contact piece ,12 through the fingers or members 13 and 16 and the rock shaft 19and its support 20 to the metal contact piece 17.

In order to operate the contact fingers or members successively when the main switch is closed, I provide a lever 30 'which is mounted upon a pivot pin 31 and is operated by a solenoid S. The solenoid S has a core 32 connected by a link 33 to a pin 34 which is secured within an insulated bushing 35 extending through the lever 30. One end of the lever 30 is connected to the piston 36 of a dash pot 37 and the longer arm of the lever has a plate or facing of insulating material 37 secured to its outer or forward side and a weight 38 secured to its rear side. This lever is so arranged that in its normal position when the motor is not in operation, its longer arm will be interposed between the contact fingers or members 13 to 16 inclusive and the base b of the starter, thus preventing the engagement of the contact fingers with the contact'pieces 12 to 17 inclusive. When the main switch is closed the solenoids S and S are simultaneously energized, the

former instantly forcing th'e contact fingers, with spring pressure, against the insulatingpiece 37 on the interposing lever 30, and the latter solenoid causing the lever to move slowly upward, the lever being retarded in its movement by the dash pot. The lower edge 37 of the insulating piece 37 is so formed that as the interposing lever moves upward the contact fingers or members 13 to 16 will be released successively from its lower edge and will engage their respective contact points or pieces connected with the starting resistance. In Fig. 1. the interposing lever is shown in its normal position in the rear of the contact fingers; in Figs. 5 and 6 the lever is shown partly raised with some .of the fingers released and the remainder still resting upon the insulating piece 37. In Fig. 3 the interposing lever is shown in full lines atabout the limit of its upward travel, with all of the fingers released. In the latter position the starrting resistance is entirely shunted.

When the interposing lever reaches the upward limit of its travel the solenoid S is denergized in the manner hereinafter described, either by the interruption of its circuit or the inclusion-in its circuit of a high resistance, while the solenoid S .remains energized until the main switch is opened or the line circuit otherwise interrupted. The solenoid S, therefore, continually presses the contact fingers against the contact pieces 12 to 17 inclusive, while the motor is' in After the interposing lever has moved operation. upward and the solenoid S is denergized the lever drops back into the position shown in dotted lines in Fig. 3 and rests upon the end of the contact finger 16. The lever remains in this position until the switch is opened or the'line circuit interrupted, when the core 26 of the solenoid S drops downward and pulls the contact fingers outwardly thus allowing the interposing lever to drop into the position shown in Fig. 1.

In Figs. 1 and 3 the solenoids Sand S are connected in independentcircuits. As shown in these figures one terminal 40 of the solenoid S is connected to the binding post 29 and thence through wire 28 to the auxiliary contact piece 27 of the main switch. The other terminal 41 of the solenoid is connected to a wire 42 which extends between a circuit interrupting device D and a contact plate 43 arranged upon the front of the starter. A crescent-shaped circuit-closing device 44 which is mounted upon a pivot pin 45 back of the inte'rposing lever normally rests upon the contact plate I 43 and a wire 46 connects said closing device with the wire 4 extending to the contact piece 3 upon the main switch. The circuit for the solenoid S is thus complete from opposite terminals of the main switch, when the parts are in their operative positions through wire 28, terminals 40 and 41, wire 42, contact plate 43, circuit closing device 45, wire 46, and wire 4 to the terminal 3. The wire 46 is also connected to the pivot pin 31 of the interposing lever 30 which is made of metal. When the main switch is closed, therefore, the solenoid S will cause the interposing lever to move upward. The pin 34, which is insulated from the interposing lever engages the upper arm of the crescent-shaped circuit closing device and turns the latter about its pivotal point, as shown in Fig. 3, until, toward the end of the movement oi the lever the device 44 leaves the upper end of the contact piece 43 thus interrupting the circuit of the solenoid S between these two points. Before the device 44 leaves the contact piece 43, however, a metal pin 49 upon the outer end of the interposing lever engages the lower edge of a swinging arm 50 of the circuit interrupting device D, and the circuit of the solenoid S is thus maintained through the wire 42,.interrupting device D, pin 49, lever 30 and wire 46, after the circuit closing device 44 has left the contact plate 43. As this engagement of the pin 49 with the swinging arm 50 occurs before t e interrupting device 44 leaves the plate 43, no spark occurs between said device and plate. As the lever continues to move upwardly the swinging arm 50 is rocked, as shown in Fig. 3,.forcing back a spring pin 51 upon the circuit interrupting device. As soon as the pin 49 passes the Cir between the pin and arm and preventing an are between these parts. The interposing lever thendrops downward until it rests upon the top of the arm l6 as shown in dotted lines in 3 and the swinging arm 50, after its oscillation rests in a horizontal position, as shown in dotted lines in said figure, beneath the pin 49. An insulating piece 52 is arranged upon the upper side of the swinging arm to prevent the latter from making contact with the pin 49 if the arm should be thrown against it after it has been returned by the spring pin, or it from any cause the main switch or the line circuit should be opened and immediately closed.

It will thus be seen that in Figs. 1 and 3 the circuit of the solenoid S is interrupted and the solenoid thus deenergized after the motor has been started, preventing further consumption of current by said solenoid. The lower-solenoid S is wound with fine wire of high resist-- ance and consumes a comparatively small amount of current.

When the interposing lever drops downward behind the contact fingers or members,when the main switch is opened, the pin 34 upon said lever engages the lower arm of the crescent-shaped circuit closing device 44 and rocks said device until its lower arm engages a stop pin 54 upon the front plate of the starter. This stop pin limits the downward movement of the circuit closing device and also oithe lever. In the normal position the pin 34 rests upon the lower arm oi said circuit closing device.

In Fig. 6 I have shown a modified arrangement of the solenoid circuits, the two solenoids S and S being connected in series, instead of in independent circuits, as in Figs. 1 and 3.

In Figs. 1 and 3 the solenoids are in independent circuits and as the solenoid S is'the only-one which is to be affected by the interposition of a high resistance or the interruption of the circuit, in said figures, after the motor has started one terminal of said solenoid is connected to the circuit interrupting device D and the plate 43, the other terminal being connected to the auxiliary contact 27 on the main switch. In Fig. 6 the arrangement is substantially the same, except that as the two solenoids are connected in series, there being but one solenoid circuit one terminal of said circuit is connected to the auxiliary contact piece 27 and the other terminal is connected to the circuit interrupting device D and the plate 43. As shown in Fig. 6 the solenoid circuit extends from the contact piece 27 on the main switch through wire 28, binding post 29, and wire 40 to the solenoid S, thence by wire 55 to the solenoid S, and thence by wire 56 to the circuit interrupting device D and the plate 43 of the circuit closing device E. A high resistance 53 is arranged between the wire 56 and the Wire 46. It will be evident that when the interposing lever passesthe swinging arm 50 of the .device D, the solenoid circuit will not be entirely ..resistanc e is interposed in the solenoid circuit, the

solenoid S will have suflicient power to hold the core 26 against the armature 57 and thus hold the contact fingers in engagement with the contact pieces connected to the starting resistance, while the solenoid S, which is wound with fewer turns oi coarser wire,

will not have sufficient energy to support its core and the inter-posing lever after the resistance has been interposed in the solenoid circuit.

When the main switch is opened and the contact fingers are drawn backward away from the contact pieces 12 to 17 inclusive, the armature circuit is interrupted between the contact pieces 12 and '13, a double air gap being formed between said contact pieces and the cooperatingparts 12 and 13, respectively. The blow out magnet M blows out any are which may be formed between the metal contact piece 12 and the arm 12'.

As the solenoid circuits are connected, at one end to an independent or auxiliary contact piece 27 upon the main switch, it will be seen that when the main switch is opened, the solenoid circuit or circuits will be entirely interrupted, and will not be affected by the counter-electro-inotive force of the motor. If the solenoid S were connected directly to the terminals 3 and 7 of the switch or to the wires leading to the motor, the counter-electro-motive force oi the latter would affect the solenoid and prevent its core from dropping immediately after the opening or" the switch.

In my improved starting device it will-be noted thatI have dispensed entirely with sliding contacts in connection with the starting resistance. As automatic starters are usually operated at a distance from the person closing the main switch, it is desirable to dispense with sliding contacts which frequently burn and prevent the movement of the contact arm.

As the motor circuit is normally open between the contact pieces 12 and 13, only a small current passes through the main switch A at the instant when the latter is closed. When the interposing device moves upward allowing the first contact member 13". to

spring downward against the contact pieces 12 & 13,

the armature circuit. is then closed through the entire resistance. Immediately following the opening of the main switch the contact members are pulled outward, interrupting the circuit between the contact pieces 12 and 13. At the moment when the switch A is opened, the contact members being then in engagement with their respective contact pieces, it will be seen, by following the field and armature circuits in Fig. 1, that the discharge from the field can pass through thearmature, so that the discharge from the field will not cause arcing at the main switch when the 1. In an automatic starter for electric motors, the combination with the motor circuits, including 8. starting resistance having contact pieces, of a series or independently movable fingers, an interposlng device normally pre venting the engagement of said fingers with the contact pieces, a rock shaft having arms thereon, springs inter posed between said arms and the fingers, a solenoid having; its core operatively connected to the rock shat a second solenoid having its core connected to the inter-posing device, and means for reducing the current in said second solenoid after the inter-posing device has been moved to release said fingers.

2. in an automatic starter for electric motors, the com bination with the motor circuits, including a starting re sistance having contact pieces, of a series of contact members movable toward and from said contact pieces, an in tel-posing device movable in a plane transverse to the planes of movement of said contact members, electromagnetic means for moving said interposin device out of the paths of movement of said members, and means for moving said members into the path of movement of said interposing device when the current is turned on. whereby said inter-posing device is held out of its normal position by said members while the motor is running".

In an automatic starter for electric motors, an armsture circuit, including a starting resistance having contact pieces, contact members arranged to open and close the armature circuit of the motor and to introduce and cut out said resistance, an ciectro-magnetic device for operating said memhers,-a circuit for said device, and a main switch having terminals for the motor circuits and having an independent terminal for the circuit of said device, said switch being adapted to make and break connections be tween both of said circuits and the line circuit.

4. In an automatic starter for electric mctors a starting resistance having contact pieces, contact members an ranged to cooperate with said contact pieces, an interposiug device adapted to normally prevent the engagement of said contact members with said contact pieces, and means for movingsaid interposing device from normal position when the current is turned on, one of said contact members being arranged to hold-said interposing device out of normal position after the motor is started.

or In. an nutomati. starter for electric motors, the conr said members when the current turned onv (S. In an automatic starter for electric motors, the combination with independently movable contact members and means for operating the same, of an interposing lover, a solenoid for operating said lever, a circuit for aid solenoid,

circuit closing device nrran od in said c it and niov-- able by said lever to open p0: tion, and a b\\'lllg,"lllf," cir nit interrupter adapted to be engaged by said lever before the circuit closre' device is moved to open position and to be tripped by said lever after the circuit closing devi c has opened, said lever and said interrupter being connecled lo the solenoid circuit at opposite sides 01' the circuit closing device.

t. In an automatic starter for electric motors, the conibination with a solenoid and a lever operated thereby, oi

- means for interrui iting the solenoid circuit comprising a swinging circuit interrupter having a metal surfaceuulnpted to be engaged by the lever during, the movement or the latter in one direction and having a surface of insulating material adapted to be engaged by the lever during itsmovement in the opposite direction.

.In testimony whereof I ailix my signature, in presence of two Witnesses.

WILLIAM C. O'BRIEN.

Witnesses HOWARD E. Cnusn, 'lrros. H. Dnivnn.

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