US970478A - Circuit-controlling device. - Google Patents

Description

P. DUNNING. CIRCUIT CONTROLLING DEVICE. APPLICATION FILED JUNE 10, 1910.

Pa'tQnted S'ept.20,1910.

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Inventor ParKer Dunnm His Attorn 7 NM wN Witne P. DUNNING. CIRCUIT CONTROLLING DEVICE. APPLICIATION FILED JUNE 10, 1910.

Patented Sept. 20, 1910.

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8 Inventor" Witness V m 6 W O t D /t F A e E K H r. 8 0| UNITED STATES PATENT OFFICE.

PARKER DUNNING, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC V I COMPANY, A CORPORATION OF NEW YORK.

CIRCUIT-CONTROLLING DEVICE.

Specification of Letters Patent.

Patented Sept. 20, 1910.

Application filed June 10, 1910. Serial No. 566,182.

To all whom "it may concern: 7

Be it known that I, PARKER DUNNING, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in CircuitControlling Devices, of which the following is a specification.

This invention relates to the control of electric circuits and has for its object the provision of an improved circuit controlling device in which the opportunity for mishandling is reduced to a minimum and which, at the same time, is simple in 0011- struction and eliicient in operation.

My invention relates more particularly to controlling devices of the type used for controlling electric motor circuits, especially with reference to the starting of the motors and bringing them up to running speed.

My-invention is particularly adapted to the starting of induction motors of the squirrel cage type in which a starting device, such, for instance, as a transformer, is first connected in the circuit to increase the current and reduce the voltage and is afterward cut out and the motor connected direct to the supply circuit.

My invention relates further to the arrangement.- of parts and combination of elements hereinafter set forth and particularly pointed out in the claims appended hereto.

In the drawings showing my invention embodied in concrete form, Figure 1 represents a side view, partly in section, of a complete starting device; Fig. 2 represents an end view partly in section of the same; Fig. 3 represents a somewhat similar view, showing the no-voltage release attachment; Fig. 4 is an outside view of the opposite end showing the latch for the o erating handle; and Fig. 5 is a diagram of the circuit connections.

Referring to the drawings, 10 represents a casing in which the transformer coils are completely inclosed. The particular type of transformer which I have employed is that known as the auto-transformer or compensator. The lower part 11 of this casing, is preferably separable from the re mainder and is adapted to receive oil or the like, since the circuits are broken in this compartment. Mounted at about the juncture of the upper and lower parts of the casing is the shaft 12 adapted to be rotated switches by means of an operating handle 13 secured to one end, while the other end is provided with a latch 14. This shaft 12 is arranged to operate two contact bars 15 and 16, carrying contacts 17 and 17 respectivcly, arranged to engage cooperating fixed contacts 18 and 18. These contact bars 15 and 16 are moved up and down, so that the contacts 17 and 17 are moved into and out of engagement with the fixed contacts 18 and 18 by means of lever arms 19 and 20, respectively, which are loosely mounted upon each end of the shaft. The two arms 19 are connected with the contact bar 15 by the pivoted rods 21 which pass through guides 22 in their up and down movement. The lever arms 20 have a similar connection by means of the rods 23 with the contact bar 16. vided with lugs 21 connected by a spring 25, the arrangement being such that the spring normally tends to move the arms together and depress the bars 15 and 16. A dog 26 is likewise secured to each end of the shaft and is provided with a lug which projects between the two arms, there being a slight amount of clearance between the pro jection and the arms, as shown in dotted lines at 27 in Fig. 2. Each of the arms 19 and 20 is likewise provided with a projection 28 adapted to engage a corresponding fixed stop 29 when the bars 15 and 16 are in the lower position; that is, when the are open.

From the construction thus far described, it will be obvious that if the operating handle 13 is moved to the right in Fig. at, so as to turn the shaft 12 (Figs. 2 and 8) in a counterclockwise direction, the dog 26 at each end of the shaft will engage the corresponding lever arm 19. This will rotate the arm 19 and move the contact bar 15 upward so that the contacts 17 engage their corresponding stationary contacts 18. This movement takes place in oppos1tion to the tension of the'spring 25. This same spring tension likewise moves the lever arm 20 downward, or at least tends to move it downward, in case it should be raised. In other words, the bias or tendency of both of the switch arms 19 and 20 is toward the lower ing of the contact bars 15 and 16. If, however, the contact bar 16 should be raised, the lug 28 on arm 20 will engage the corresponding lug 28 on arm 19 and force it The two arms 19 and 20 are pro rotated and the bar 16 raised, this movement downward. This positively prevents the 1 closing of the contacts on the bar 15, while the contacts on the bar 16 are closed. In the same way, when the handle is turned in the opposite direction, the lever arm 20 is also lowering the contact bar 15.

In order to secure the contact bar 1( in raised position, I provide a pivoted locking member 30 having a shoulder 30' adapted to be engaged by the latch let when the shaft 12 is turned to the limit of its movement in a clockwise direction. This locking memher is slotted to receive a. pin 31 to limit its movement. Theopposite end of the member is provided with a hub through which the rod 32, attached to the core 33 of the no-voltage magnet 34:, passes. A nut 35 is screwed on the rod for lifting the latch. The arrangement is such that when the core 33 drops, it engages the locking member and releases the latch 14, thereby permitting the switch parts to return to their normal position. When the magnet is energized, the core raises and the nut 35 lifts the latch.

In the drawings I have shown my starting device as connected to an auto-transformer for starting squirrel cage induction motors. The contacts 17 on the bar 16 are connected direct to the line. Three of the six contacts 17 on the bar 15 are connected direct to the motor, while theother three are connected direct to line. The arrangement is such that when the bar 15 is raised the motor is connected to the supply circuit through the auto-transformer, while when the bar 16 is raised the motor is connected directly to the line. It is necessary, therefore, that provision be made for preventing the movement of the arm to the running position, in which the motor is connected directly to the line, before it is moved to the starting position in which the auto-transformer is in circuit. In order to prevent this, I provide the arrangement shown in the patent to Gehrkens, 809,677. This consists of a latch 36 pivoted at 37 and having cut-away portions at 38 and 39, the cut-away portion 38 being provided with a square shoulder. A lug 40 is secured to the handle, so that in the normal position of the operating handle it engages the square shoulder of the latch. The handle, therefore, cannot be turned to the left in Fig. at, but must be turned to the right. After it is moved to the right, or into the starting position, it must be moved to the left quickly, otherwise the handle will be stopped at its central position by the lug. If, however, it is moved quickly, the latch will be raised and the handle may be moved to running position in which it will be locked by the latch 14.

The operation of my device taken as a whole will now be seen to be as follows: To

start the motor the operating handle 13 is first moved to the right in Fig. 4. This movement raises the-contact bar 15 and connects the motor M te the three-phase supply circuit A, B, and 0 through the auto-transformer T. The handle 13 is then moved quickly to the extreme left and in doing so the contact bar 15 is lowered and the autotranst'ormer cut out of circuit. The same movement raises the contact bar 16 and connects the motor directly to the line. At the same time the switch is held in this position by the latch 14. The no-volt-age magnet 35 may be connected across one phase of the circuit as shown. On failure of voltage, the latch 14 will be tripped, 'the motor circuit opened, and the parts returned, tenor-mal position.

It will be seen that by my arrangement the switch arm cannot be moved to the running position without first being moved to starting position. It is also impossible to have the starting and running contacts both closed at the same time. Furthermore, upon the occurrence of abnormal circuit conditions the parts are all restored to their normal condition, so that when the motor is again started, the auto-transformer will be in circuit.

While I have described my invention as embodied in concrete form and as operating in a specific manner in accordance with the patent statutes, it should be understood that I do not limit my invention thereto, since various modifications thereof will suggest themselves to those skilled in the art without departing from the spirit of my invention, the scope of which is set forth in the annexed claims.

What I claim as new and desire to secure by Letters Patent of the United States, is,

l. A starting device for electric motors comprising a starting switch and a running switch both biased to open position, an opcratin handle movable independently thereof and arranged to close the starting switch and open the running switch when moved in one direction and to close the running switch and open the starting switch when moved in the opposite direction, and electrically controlled means for locking the running switch in closed position.

2. A starting device for electric motors comprising a starting switch and a roaming switch pivoted concentrically and both biased to open position, an operating handle pivoted concentrically with said switches and movable independently thereof, said handle being arranged to close the starting switch and open the running switch when moved in one direction and to close the running switch and open the starting switch when moved in the opposite direction, and electrically controlled means for locking the operating handle inrunning position.

3. starting device for electric motors comprising a starting switch and a running switch pivoted independently of each other and both biased to open position, an operating handle therefor arranged to close the starting switch and open the running switch when moved in one direction and to close the running and electrically controlled means for locking he running switch in closed position.

4. A starting device for electric motors comprising a transformer, a normally open switch for connecting the motor to the supply circuit through the transformer, a second normally open switch for connecting the motor directly to the supply circuit, an operating handle movable independently of said switches and arranged to close one of the switches when moved in one direction and the other of the switches when moved in the opposite direction, means for preventing both of said switches from being closed at the same time, and electrically controlled means for locking said closed position.

5. A starting switch for electric motors comprising a pair of concentrically pivoted switch arms having contacts connected therewith, an operating handle pivoted concentrically Wit-h said arms and movable independently thereof, a member movable with said handle provided with means for moving one of said arms when moved in one direction and the other of said arms when moved in the opposite direction, elecsecond switch in trically controlled means for locking one of said arms in operative position, and means for preventing the movement of both of said arms to operative position at the same time.

6. A starting device for electric motors comprising a starting switch and a running switch, an operating handle movable independently thereof and arranged to close the starting switch and open the running switch when moved'in one direction and to close the running switch and open the starting switch when moved in the opposite direction, and electrically controlled means for locking the running switch in closed position.

7. A starting device for electric motors comprising a starting switch and a running switch pivoted concentrically, a spring connecting said switches and normally tending to open the same, an operating handle pivoted eccentrically with said switches and having a projection arranged to engage one of said switches when moved in one direction to close the same and the other of said switches when moved in the opposite direction to close the same, a locking device for holding the operating handle in running position. and electrically controlled means for releasing the handle to open the running switch on the occurrence of abnormal circuit conditions.

In witness whereof, I have hereunto set my hand this 9th day of June, 1910.

PARKER DUNNING.

\Vitnesses BENJAMIN B. HULL, HELEN ORFORD.

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