US1003915A

US1003915A - Automatic motor-starter.

Info

Publication number: US1003915A
Application number: US4877??09A
Authority: US
Inventors: Charles D Knight
Original assignee: General Electric Co
Current assignee: General Electric Co
Publication date: 1911-09-19
Anticipated expiration: 1928-09-19

Description

.G.DLKNIGHT. AUTOMATIC MOTOR STARTER. APPLI-OATIOI FILED JUNE 1 Flql.

llllllllllllllll llllllfllUJ ll 0, 11107, nmmwnn APR. 3, 1909.

Patented Sept 19,1911.

INVENTUR CHARLES E]. KNIGHT.

i 0.1). KNIGHT.

v -AUTOMATIO MOTOBYSTARTER. APPLICATION FILED JUNE 1 0, 1907. RENEWED APR 3, 1909.

2 SHEETS-BREE! I.

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W ITY N E55 E51 VINVENITDR 01 6251 I EHARLE UKNJBHT JJ A; QQQX b 14 Arm.

- Patented'Sept. 19, 1911;

cam D. KNIGHT,

0F SC'HENECTADY, NEW YORK, ASIGNOR TO GENERAL ELECTRIC COMPANY. A COBPOB ATION 01 NEW YORK AMO'MATIU" MOTOIhSTLBTEB.

Application llled June, 10, 1007,

To all whom it may concern:

it" known that 1, CHARLES D. KNIGHT, a citizen of the United States, residing at Schenectady, county. of Schenectady, State of New York, have invented certain new and useful Improvements in Automatic Motor-Starters,of which the following is a specification. i

- This invention relatesto means for controlling electric motor circuits and has for its obi'ect the provision of a device whereby operation and circuiting.

an e ectric motor may be started an brought u to running speed in a reliable,

safefland e cient manner.

Specification of Letters Patent. Serial No. 878,255. Renewed April 3, 1909. Serial No. 687,7.

My invention relates more specifically to the starting of alternating current motors of. the type which are'controlled by connecting them to a source of low voltage forstarting and then increasing the impressed voltage for running.

One of the objects of my invention therefore is to provide a simple and eflicient automatic starter for alternating current circuits b means of which motors may be control ed from a distance either manually or by automatic switching devices, such as prl-(essure governors, float switches and the In carrying out my inventionI. provide in connection with a .transformer, a plurality of switches arranged to first connect the source of current with the motor through the transformer and then connect the motor directly to'the of current.

More specifically I provide two solenoids witches which are so arranged as to deenergize the solenoids when the-switch. is in 7 h pivoted respectively at 30 the switc in operative engagfng I with fixed carbon contacts 32 and 33'. T 098 it releases the locking device of the first solenoid and simul-- taneously energizes the second solenoid thereby cutting out the transformer, and connecting the motor directly .to the line.

My invention will be more clearly comprehended by a reference to the accompanying drawings in which I have shown my 1nvention embodied in concrete mechanism for purposes of illustration.

Patented Sept. 19, 1911.

In these drawings, Figure 1 is a frontelevation of my complete device; Fig. 2 is a" side elevation of the same, the oil tank being partially broken away to show the switches; Fig. 3 is a plan view of the device; Fig. 4 is a detail of the latchin mechanism;-and Fig. 5 is a diagram 0% the circuits.

.Referring to the drawings, I shall first describe the mechanical features of my devicevand shall then proceed to describe the Referring therefore to Figs. 1 to 4, 10 in an insulating panel of slate or soa supported in a vertical position y the standards 11, on the front of which my switching mechanism is mounted. The switching mechanism proper consists of two stone,

solenoid switches 12and 13 havingcores 14 u and 15 respectively. The core 14 has secured to its lower end a frame-work .for supporting six laminated brushes 16:17, 18, 19, 20 and 21 each adapted to bridges, of corresponding contacts 16, 17 18', 19',

'20, and 21 when the core is in a raised position; Secured to the lower end of the core l5=is a frame-work for supporting a similar "'set of three brushes22, 23 and 24 likewise adapted= to brid corresponding contacts 22', 23" andv24" w en the core is in its raised position. A tank 25 adapted to be filled with oil is secured which 'rojects from the panel, by means of pivot bolts 26. These bolts fit into slotted r527 so that the tank can be easily loweredor removed. Above each of the

soles noids

12 and 13 are switch

arms

28 and 29 and 31 alt-their free ends carbon contacts switch arms are arranged directly overt-t to. the contact board 25,-

pair

cores 14 and '15 and are adapted to be e'ngaged by. projecting rods 34 and 35 on-the ends of the cores. The

carbon contacts

32 and 33 are thus separated as the coresl and 15 are drawn into their respective solenoids. The

switches

28 and 29 open the'circuits of their corresponding solenoids and in order to maintain the cores of the sole noids in a raised position after the solenoids are de nergized, I rovide a'latching rmechanism, the detai s *of which are 'shown'in Fig. 4. The looking or latching devices of both solenoids are the same and consist of a latch {36 pivoted at 37=jto the plate 38 .on the upper end of the solenoid. The latch is provided with a perforation 39 adapted to admit the rod 34 and also a slot 40 coiiperating with a pin 41 in the plate 38 to limit the movement of the latch. The rod 34 is provided wih a groove 41 arranged to be engaged by the latch 36 and hold the rod 34 in a raised position. The spring 42 attracts the latch into the groove as shown in Fig. 4. A lever 43 pivoted at 44 to a bracket 011 plate 38 coiiperates with the latch. This lever has a lip 44 at one end to engage the latch and at its opposite end extends in a horizontal direction so as to be engaged by core 45 of magnet 46. A

" similar core 47 controlled by solenoid 48 the spring acts upon the rod 35 of core 15. It will be seen that when the magnets 46 and 48 are deenergized, the cores are down and exert pressure upon their corresponding levers 43. This forces the latch against the tension of 42 so that the rod will pass freely through the perforation 39. When, however, the

cores

45 and 47 are raised, the springs 42 exert a tension upon the latch so that the rod 34 is raised until the groove 41 reaches the latch 36, and the latter enters the groove locking the same in place. When thercore drops upon the lever 43, the latch 36 is forced over and releases the rod 34, allowing the core 14 to drop therefore caus-' ing the switches secured thereto to drop. A solenoid 49 is mounted upon the panel adjacent to the solenoid 12 and is provided with a core, the lower end of which has a piston (see Fig. 5) operating in a barrel 50 so as to constitute a dash-pot. The upper end of the core passes loosely through contactor 51 adapted to move between the c'on-' t acts 52, 52, and 53, 53. A collar 54 on the rod engages the contactor and forces it to bridge

contacts

52, 52, and a spring 55 between the contactor and bearing block 56 forces the contactor into engagement with the

contacts

53, 53.

he arrangement of circuits and the mode of operation are as follows: I have shown my device in use on a three-phase circuit, of which 57, 58 and 59 are the main or supply conductors. M is a three-phase motor and G is the starting compensator or autotransformer having three

branches

60, 61 and 62, one for each phase. A control circuit is tapped off from the

conductors

57 and 58 and a step-down transformer 63 reduces the potential to the desired point for control purposes. The switch 64 may be operated manually or in any desired man ner, as for instance by a float switch or the like. When the switch 64 is closed, four

solenoids

12, 46, 48 an 49 are simultaneously energized. The control current passes from switch 64 througi solenoid 46 and also in parallel through the solenoid 12 to the point 65, current to the solenoid 12 passtor 7 8, solenoid The circuit of the solenoid 48 is independ ently completed as follows: from switch 64, conductor 69, solenoid 48 and conductor 67. The circuit of solenoid 48 therefore can only be opened and closed at the switch 64. The

solenoid 12 being energized draws up'its core and closes the switches 16, 17, {18, 19, 2.0,andv 21 which connect the

main conductors

57, 58 and 59 toone end of the

transformer sections

62, 61 and and also taps70, 71 and 72 with the three

phases

73, 74 and 75 of the motor. The taps of the transformer are so arranged as to give the desired starting potential to the motor, and may be adjusted as desired. When the core 14 rises, the rod 34 at its upper end engages the switch arm 28 and opens the circuit of solenoid 12. Solenoid 46, however, is energized'and by raising its core allows the latch 36 to engage the groove 41 in the rod 34 and hold the core in a raised position. Solenoid 49 also being energized attracts its core butthis core is retarded by the dash-pot which may have its speed regulated by the valve 76. The piston moves upward slowly until it reaches the perfora- 60 respectively tions 77, when the dash-pot'is suddenly released and the core moves upward quickly. The collar 54 strikes the contactor 51 and moves it quickly upward so as to bridge the

contacts

52, 52, and break the circuit at 53, 53. When the contactor leaves the

contacts

53, 53 the solenoid 46 is deenergized and the core 14 thereupondrops cutting off the compensator G. I The circuit of solenoid 13, however, is immediately closed through contacts 52, 52', the circuit now being as follows: from switch 64 to arm 28, conduc- 13, conductor 79, contactor 51, switch arm 29 and condfictor 67. The

core 15 is thereupon drawn up and the cir cuit is.closed. from the main conductors 57,

.58 and 59 directly to the motor through

brushes

22, 23 and 24, and conductors 80,81 and 82 respectively. When the core l5'rises the circuit of the solenoid 13 is opened but the core is prevented from dropping by the latching mechanism since the solenoid 48 is all of the time energized. 'This solenoid 48 operates as a no-voltage magnet and upon failure of voltage will release the core 15 and'open the circuit. The same thing will happen if the circuit is opened at switch 64. It should be noted that when the switch 29 is opened the circuit of the solenoid 49 is likewise opened. and the core drops back quickly, the dash-pot not operating on the return movement.

While the motorthcn is .130

normal conditions solenoid 48 running under the energizing erris the only coil energized,

cuit of the others being opened at switch 29.

without departing from the sp It will be seen that I have provided a very simple and efiicient method of starting alternating current What I claim as new and desire to secure by Letters Patent of the United States, is,-

1. A starter for electric motors'comprisin a transformer, a plurality of magnetica ly-operated switches for-first connecting the motor to the supply-circuit through the transformer and then connectingthe motor operated switches trolled means for. locking said switches in directly to the supply circuit, and electri- (tally-controlled means locking said switches in operative position. 23 A'starter for electric motors comprisa transformena] plurality of magnetiml -op erated switches for first connecting the motor to the supply circuit through the transformer and then connecting the motor directly to the supply circuit, a master controller for the switches, trolled means for mechanically locking said switches in operative position.

- 3. A starter for electric motors comprising a transformer, a plurality of magneticallyfor first connecting the motor to the supply circuit through the transformer and then connecting the motor directly to the supply-circui.t, an electricallycontrolled device for mechanically locking one of said switches in operative position, and a master controller for said switches and said lockin device.

4.. A starter ing a transformer, a magnetically-operated switch for connecting the sup ly circuit to the transformer and the trans .ormer to the motor, a second magnetically-operated switch for connecting the supply circuit directly to the motor, and electrically-conoperative position.

5. A starter for electric motors comprisi a transformer, a plurality of solenoi switches for first connecting the motor to the supply circuit through the transformer and then connecting the motor'directly to the supply circuit, means for'deenergizing said solenoids when the switches are moved to the operative position, and electrically controlled means for locking said switches in said position 6(A starter for electric motors comprising avtransformer, a plurality of solenoid switches for firstconnecting the motor to the arrangement being such that only a no-voltage magnet is enerfor mechanically and electrically-con-- or electric motors comprising a transformer,

the supply circuit through the transformer and then connecting the motor directly to the supply circuit, meansfor deenergizing said solenoid when the switches are moved to the operative position, means for locking said switches in said position, and a master controller for said solenoids.

7. A starter for electric motors comprising a transformer, a plurality of solenoid switches for first connecting the motor to the supply circuit through the transformer and then connecting the motor directly to the supplycircuit, means for deenergizing said solenoids when the switches are moved to the operative position, means for locking one of said switches in said position, master controller for locking device.

8. Astarter for electric motors comprising a transformer, a solenoid switch for connecting the motor to the supply circuit through the transformer, means for deenergizing said solenoid when the switch is moved to the operative position, means for locking said switch in said position, a second solenoid switch for connectingthemo- .tor directly to the supply circuit, and a master controller arrangedto release the said locking device and simultaneously energize said second solenoid.

9. A starter for electric motors comprising a transformer, a solenoid switch for connecting the supply circuit to the transformer and the transformer to the motor, means for deenergizin said solenoid when the switch is moved to 518 operative position, electrically-controlled means for locking said switch in said position, a second solenoid switch for connecting the motor directly to the supply circuit, and a master controller arranged to release the said looking device and simultaneously energize said second solenoid.

10. A starter for electric motors comprisa solenoid switch for and a said solenoids and saidconnecting the supply circuit -to the transformer and the transformer to the motor,

means for deenergizing said solenoid when the switch is moved to the operative position, electrically-controlled means for looking said switch in said position, a second solenoid switch for connecting the motor directly to the supply circuit, means for de. energizing said second solenoid when the switch is moved to the operative position, an electrically-controlled locking device for said second switch, and

and simultaneously energize said second sole-- noid. p 1

11. A starter for electric motors comprising an impedance, a plurality of solenoid the-supply circuit'th'rough the impedance and, then connecting the motor directly to a master controller arranged to release said first lockmg device switches for first connecting the motor to the supply circuit, independent electrically ckintrolled means for locking each switch in operative position, and means for dccnergizing each solenoid as its switch is moved to operative position.

12. A starter for electric motors comprising a transformer, a plurality of magnetically-operated switches for first connecting the motor to the supply circuitthrough the transformer and then connecting the motor Copies of this patent may be obtained for five cents each, by adiiressin Washington, D. G.

directly to the supply circuit, and electri-' CHARLES D. KNIGHT; \Vi tnesses BENJAMIN B. HULL, MARGARET E. WOOLLEY.

g the Commissioner of Patents,