US958805A - Rheostatic controller for electric motors. - Google Patents

Description

F.D.HALLOGK. RHEOST ATIO CONTROLLER FOR ELEGTRIG MOTORS.

APPLICATION FILED JAN. 3, 1910.

958,805. Patentd May 24, 1910.

QOQQ G O TTORNEY UNITED STATES OFFICE.

FLETCHER D. HALLOCK, OE PITTSBUKG, PENNSYLVANIA, ASSIGNOR. TO WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY,YA CORPORATION OF PENNSYLVANIA.

RHEOSTATIC CONTROLLER FOR ELECTRIC MOTORS.

To all whom it may concern:

Be it known that I, FLETCHER D. HAL- LocK, a citizen of the United States, and a resident of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Rheostatic Controllers for Electric Motors, of which the following is a specification.

My invention relates to rheostatic controllers for electric motors and it has for its object to provide a device of this character that shall be adapted to regulate both the armature and field resistances of elec tric motors and that shallcomprise two contact arms, one of which is adapted to govern the other.

. In my co-pending a plication, Serial No. 536,055 filed of even ate herewith, I have illustrated and described a regulating rheostat for electric motors comprising a pair of contact arms which may be mechanically interlocked for concurrent operation in both directions, the arrangement of parts being such that one of the arms may be released from the other and independently operated.

According to my present invention, I provide two arms which correspond to those in the application just referred to, but, instead of the mechanical interlock, I provide an electric circuit switch on one arm by which an electro-magnet, that governs the position of the other arm, may be controlled. In this arrangement, one of the arms is provided with a retracting springan electro-magnet being provided for holding the arm in opposition to the spring in any of the controller positionsand the second arm is provided with an operating handle and is adapted to carry the first arm with it in one direction but may be adjusted independently of the first arm in the opposite direction.

Figure 1 of the accompanying drawings is a front elevation of a controller constructed in accordance with my invention. Fig. 2 is a fragmentary view at right angles to Fig. 1 showing the outer end of one of the arms, and Fig. 3 is a diagrammatic view showing the circuit connections for the controller of the other figures.

Referring to Figs. 1 and. 2 of the drawings, the structure here shown comprises a slab or face plate 1 of insulating material on which a series of armature-resistance contacts 3 and field-resistance contacts 2 are Specification of Letters Patent.

Application filed January 3, 1910.

Patented May 24, 1910.

Serial No. 536,053.

mounted, a pair of contact- bearin arms 4 and 5 and an electro-magnet 6. T e arm 4 is retracted to its off position by a spring 7 and is held in the other control positions by the electro-magnet 6 except when the motor circuit is interrupted, as hereinafter pointed out. Both of the arms 4 and 5 are rotatably supported on a stud 8 which projects outwardly from the plate 1 and the arm 5 is provided with a projection 9 which is adapted to engage a rib 10 of the arm 4 so that when the arm 5 is rotated in a clockwise direction, the other arm is carried with it in opposition to the spring 7.

As shown in Fig. 2, a switch 11 is provided at the outer end of the arm 5 and is normally closed, but may be opened by a push button 12 which protrudes from the end of the handle 13 that is carried at the outer end of the arm. The switch 11 is located in the circuit of the magnet 6 and, consequently, in operating the controller, the electro-magnet may be deenergized at any time by actuating the push button 12. The contacts 2 and 3 are arranged substantially in concentric arcs of circles and are respectively engaged by contact fingers 14 and 15 on the arm 5. A contact ring segment 16 is also mounted on the face plate 1 and is engaged by the contact finger 17 of the arm 4. The structural details of the push button switch 11 form no part of my present invention, and other switching devices may be substituted therefor. As shown, the op erating handle 13 is provided with a hole 18 through which a rod 19 extends, the outer end of the hole being counter-bored to receive a spring 20 and the push button 12. The inner end of the rod 19 is secured to the contact finger of the switch 11 and its outer end is secured to the push button. The electro-magnet 6 corresponds to that shown in my co-pending application, Serial No. 437 ,324, filed June 8, 1908, and is provided with a ball or sphere 21 to engage any one of a series of counter-sunk holes 22 in a segment 23 which is secured to an enlargement 24 of the arm 4 and with a core or armature which acts against the ball when the electro-magnet is energized. The arrangement of parts is such that the arm 4 is not locked in any position so that it cannot be moved, but the action of the electro-magnet is suflicient to overcome the retracting effort of the spring 7.

The operation of the device and its circuit connections may best be understood by referring to Fig. 3 in which like parts are designated by the same reference characters as in the other figures. Assuming that the controller occupies its off position and the arms 4 and 5 rest against a stop 25; if the arm 5 is moved in a clockwise direction by means of the handle 13, both arms will be operated concurrently and the contact finger 17 will come into engagement with the ring segment 16 and, afterward, the contact fingers 14 and 15 will respectively engage the successive contact members 2 and 3. Upon the engagement of the finger 17 with the member 16, a circuit is established from a positive line conductor 26 through arm 4, contact finger 17, member 16, conductor 27, field magnet winding 28 of the motor 29 and conductor 30 to the opposite line conductor 31. A full field connection is thus established and is maintained as long as contact finger 17 engages the segment 16. The contact fingers 14 and 15 are next brought into engagement with the contacts 2 and 3. The engagement of the finger 14 with the contacts 2 has no efiect upon the strength of the motor field, so long as the short circuit 27 is maintained, but a motor circuit is established from the positive line conductor 26 through arm 5, finger 15, armature resistance 32, conductor 33, armature 34 and conductor 30 to line conductor 31. The amount of resistance included in the armature circuit is gradually decreased as the finger 16 successively engages the contacts 3.

Vhen the contact arm 4 finally occupies the position shown in Figs. 1 and 3 of the drawings, the short circuit 27 of the field resistance 35 is interrupted and the field circuit is established from the arm 5 through finger 14 and one of the contacts 2 to the field winding 28, from which point the circuit is completed through conductor 30. The arm 5 may be adjusted independently of the arm 4 in a counter-clockwise direction in order to gradually introduce the field resistance 35 for the purpose of increasing the motor speed. hen the contact finger 17 of the arm 4 is disengaged from the ring segment 16, it moves into engagement with the contact member 36 which is connected to the conductor 33 and, consequently, when the arm is in this position, the armature resistance is short circuited. If it is desired to reduce the speed of the motor by strengthening the motor field, and re-inserting a portion of the armature resistance, the arm 5 may be adjusted to the proper position and the push button switch 11 actuated. Then this is done, the circuit, which was established from the line conductor 26 through the contact arms, conductor 27, magnet 6, resistance 3S, conductor 39, swltch 11 and conductor 40 to the line conductor 31, is interrupted. Following the deenergizing of the magnet, the arm 4 is released and is retracted by the spring 7 until it engages the arm 5 which is assumed to be held in position by the attendant. As soon as the arms are together, the push button switch is released and closed so that the magnet is again energized and holds the arm 4 in opposition to the retracting spring. If the supply of energy to the motor is temporarily interrupted, the electro-magnet will be deenergized and both arms will be thrown to the ofi' position of the controller by the action of the spring 7, irrespective of the positions.

which they occupy.

The circuit connections for the controller may be modified without departing from the spirit of my invention, and I desire that such modifications and minor structural variations shall be included within its scope.

I claim as my invention:

1. A controller for electric motors com prising a pair of resistance-regulating arms adapted to operate together in one direction, means for retracting one of the arms to its off position, electro-responsive means for holding said arm in opposition to said retracting means, and means carried by the other arm for rendering the holding means inoperative.

2. A controller for electric motors comprising a pair of resistance-regulating arms adapted to operate together in one direction, a retracting spring tending to throw one of the arms to its off position, an electro-magnet acting in opposition to the retracting spring for holding the arm in the operating positions of the controller and a switch carried by the other arm for controlling the circuit of the magnet.

3. In a controller for electric motors, the combination with a pair of contact-bearing arms, which are adapted to be manually operated together in one direction and one of which may be manually operated independently in the other direction, of a retracting sprin acting upon one of said arms for returning both of them to their ofl position, electro-magnetic means for opposing the action of the spring, and an electric switch carried by the second arm for governing the electro-magnetic means.

4. A controller for electric motors comprising a pair of contact-bearing arms, one of which is adapt-ed to successively short circuit the motor field and the motor armature resistances as it progresses in one direc tion, and the other of which is adapted to gradually exclude the armature resistance as it progresses in one direction and to gradually increase the field resistance as it progresses in the opposite direction, an electro magnet for opposing the movement of the first named arm and a switch carried by the ing spring for said first named arm, an electro-magnet for opposing the action of the 15 retracting spring and a switch carried by the said second named arm for controlling the energization of the electro-magnet.

In testimony whereof, I have hereunto subscribed my name this 24th day of Dec., 20 1909.

FLETCHER I). HALLOGK.

Witnesses ALBERT VAN ZANDT, B. B. HINES.

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