US958806A - Regulating-rheostat. - Google Patents

Description

F. D. HALLOCK.

REGULATING RHEOSTAT.

APPLICATION FILED Luna, 1910 Patented May 24, 1910.

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F. D. HAL-LOOK.

REGULATING RHEOSTAT.

APPLICATXQN FILED JAR.3,1910. 958 806. Patented May 24, 1910.

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UNITED STATES PATENT OFFICE.

FLETCHER D. HALLOCK, 0F PITTSBURG, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

REGULATING-RI-IEOSTAT.

Specification of Letters Patent.

Patented May 24., 1910.

Application filed January 3, 1910. Serial No. 536,055.

To all whom it may concern:

Be it known that I, FLETCHER D. HAL- LOOK, 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 Regulating-Rheostats, of which the following is a specification.

My invention relates to electric circuit controllers and it has special reference to such rheostatic controllers as are adapted for regulating both the armature and field resistances for electric motors.

The object of my invention isto provide a simple and durable rheostat of the class above indicated by means of which either the armature resistance or the field resistance of a shunt or compound wound motor may be regulated as deslred.

Motor starters have heretofore been constructed by means of which the armature resistance of a motor may be gradually cut out and afterward the resistance in the field circuit adjusted as desired, but it is frequently desirable to utilize the armature resistance for speed regulations in addition to the usual field regulation.

According to my present invention, I provide a regulating rheostat which not only combines the desirable features outlined above but is also so arranged as to automatically return to its off position if the motor circuit is interrupted.

Figure 1 of the accompanying drawings is a plan view and Fig. 2 is a partially sectional elevation of a regulating rheostat constructed in accordance with my invention. Fig. 3 is a diagram of the circuit connections for the rheostat of the other figures.

Referring to the drawings, the structure here shown comprises a stationary slab or base 1 of insulating material to which a series of armature-resistance contact members 2 and field-resistance contact members 3 are secured and are arranged substantially in concentric arcs: contact-bearing arms 4 and 5, a retracting spring 6, and an electro-magnet 7 for accentuating various armatureregulating positions which the device is adapted to occupy. The arms 4 and 5 are rotatably supported on a post 8, the arm 5 being adjacent to the base or slab l and the arm 4 being mounted adjacent to the arm 5. The arm 4 is bifurcated at its inner end and a helical retracting spring 6 is coiled about a collar 9, which is mounted on the post 8, between the arms of the lever. The outer end of the spring 6 is bent inwardly and projects through a slot 10 in the outer end of the post 8 and the inner end of the spring is bent outwardly and engages a notch 11 in the inner end of a rib 12 with which the arm 5 is provided. From the foregoing, it is evident that the arm 4 is free to rotate about the post 8 as an axis while the arm 5 always tends to occupy its ofi position in which it engages a stop 13.

The arm 4 is provided with contact fingers l4 and 15 which are respectively adapted to engage the contact members 2 and 3. The arm 5 is provided with a contact finger 16 which is adapted to short circuit the armature resistance by engaging the contact member 17 when the arm engages the stop 18 and it is adapted to engage a contact ring segment 19 when the arm occupies an inter1nediate position. The rib 12 of the arm 5 is provided with a notch 20 at its outer end in which a roller 21, which is rotatably mounted on a pin 22, is disposed.

The outer end of the arm 4 is provided with a narrow slot 23 which is parallel to the plane of the base 1 and in which a latch 24 is located. The latch 24 is secured to a pin 25 and is adapted to engage the roller 21 at the outer end of the arm 5 whenever it is desired to operate the arms together, a helical spring 26, which is located in a hole 27 at the outer end of the arm 4, being adapted to prevent the latch from being accidentally released. The pin 25 is rotatably supported at the outer end of the arm 4 and extends outwardly therefrom to receive a handle 28, which is also secured to it. The arrangement of parts is such that the latch 24 may be released by suitably rotating the handle 28. The same handle is utilized for adjusting the arms 4 and 5 together and for adj usting the arm 4 independently.

The inner end of the arm 5 is enlarged to' constitute a segmental disk projection 29 and a ring segment 30 is secured to its circumferential surface by means of screws 31. The ring segment 30 is provided with a series of counter-sunk holes 32 which are engaged by a ball 33 when the electro-magnet 7 is energized, as hereinafter pointed out. The structure of the electro-magnet forms no part of my present invention, but I prefer to employ an arrangement similar to that 110 shown and described in my co-pending application, Serial No. 437,324, filed June 8, 1908.

A quick-break switch 34 is preferably provided for the purpose of interrupting the circuit in order that an arc may not be formed when the contact fingers 14 and 15 are separated from the contact members 2 and 3, in passing to the off position of the controller.

The operation of and the circuit connections for the device are as follows :-Assuming that the arms 4 and 5 are latched together and that the controller occupies its off position, if the arms are moved in a clockwise direction from engagement with the stop 13, contact member 16 is first brought into engagement with the contact ring segment 19. At this point two circuits are established as follows one from line conductor 40 through arm 5, finger 16, magnet 7 and resistance 41 to line conductor 42; and another from finger 16 through contact 19, conductor 43 and motor field magnet winding 44 to conductor 42. The contact members 14 and 15 next come into engagement with the first of the series of the contact members 2 and 3 and the motor armature circuit is completed from conductor 40 through arm 4, finger 14, contact 2, resistance 45 and motor armature 46 to conductor 42. The field resistance is short circuited by the engagement of the contact members 16 and 19 and the armature resistance is thus entirely included in the circuit. As the arms are still further rotated in the same direction, the armature resistance is gradually cut-out by the engagement of the arm 14 with successive contact members 2 which are connected to intermediate points of the armature resistance, in the usual manner. When the contact arms finally reach their extreme position in this direction, the arm 5 comes into engagement with the stop 18 and the contact member 16, by engaging the contact member 17 short circuits the armature resistance and interrupts the shortcircuit which formerly existed to the field resistance, as shown in Fig. 3. hen the motor circuit is first completed, the electromagnet 7 is energized as above indicated so that the various positions of the arms are accentuated by engagement of the ball 33 with the counter sunk holes 32. The force exerted by the electro-magnet is sufficient to overcome the retracting effort of the spring 6 and, consequently, the arms may be left in any intermediate position for the purpose of obtaining speed regulation by means of the armature resistance. The holes 32 correspond in position to the stationary contacts 2 in order that the finger 14 may squarely engage one of the contacts in any intermediate position of the arm.

If the arm 5 occupies the position shown in Fig. 1 of the drawings and the contact member 16 engages the contact member 17, the speed of the motor may be increased by slightly rotating the handle 28 to release the latch 24 from the roller 21 after which the arm 4 may be moved in a counter-clockwise direction so that the contact members 14 and 15 sweep back over the contact members 2 and 3 in reverse order. The friction between the contact members is sutlicient to hold the arm 4 in any intermediate position unless the electro-magnet 7 becomes deenergized by reason of the interruption of the motor supply circuit or a material reduction in its voltage. Under these conditions, the arm 5 will be released and the spring 6 will return both arms to the ofi' position so that the motor windings will not be injured if full line voltage is again applied. As soon as the contact member 16 engages the contact member 17, the contact finger 14 is inactive and the contact finger 15 serves to regulate the resistance in the field circuit of the motor.

If it is desired to operate the motor at a very high speed, both arms will be rotated from the off position into engagement with the stop 18 and the arm 4 will then be released from the arm 5 and will be rotated in the opposite direction until a projection 35 engages one end of the rib 12. WVhen the arms are released and are retracted to the off position, a pin 86, which extends inwardly at right angles to an extension 37 of the arm 4, actuates the quickbreak device 34 to interrupt the motor circuit.

The size and arrangement of parts of the device shown, may be modifiedwithout departing from the spirit of my invention, and I desire that only such limitations shall be imposed as are indicated in the appended claims.

I claim as my invention:

1. A controller for electric motors comprising a pair of contact-bearing arms, means for retracting one of the arms to its oif position, means for latching the two arms together and a handle for operating both arms together and for releasing one of the arms and operating it separately.

2. In a controller for electric motors, the combination with a pair of contact-bearing arms, means for latching the two arms together, a retracting spring acting upon one of said arms for returning both of them to their off position, electro-magnetic means for opposing the action of the spring and manually operated means for releasing the second arm, whereby it is permitted to operate independently of the first.

3. A controller for electric motors comprising a pair of contact-bearing arms one of which is adapted to successively short circuit the motor field and the motor armature resistances as it progresses in one (11- subscribed my name this 24th day of Dec, rection and the other of which is adapted 1909. to radually exclude the armature resistance as it progresses in one direction and to I FLETCHER HALLOCK 5 gradually lnterpose the field resistance as it Witnesses:

progresses in the opposite direction. ALBERT VAN ZANDT,

In testimony whereof, I have hereunto B. B. HINES.

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