US958804A - Motor-starter. - Google Patents

Description

F. D. HALLOOK. MOTOR STARTER. APPLICATION FILED JAN. a, 1910.

Patented May 24, 1910.

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APPLICATION FILED JAN. 3, 1910.

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ATTORNEY Patented May 24, 1910.

UNITED STATES FiilENT OFFICE.

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

MOTOR-STARTER.

Specification of Letters Patent.

Patented May 24, 1910.

To all whom it may concern:

Be it known that I, FLEroHER 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 Motor-Starters, of which the following is a specification.

My invention relates to controllers for electric motors and particularly to such rheostatic controllers of the face plate type are adapted for starting industrial motors.

The object of my invention is to provide a simple and durable motor-starting device of the class above indicated which shall embody means for automatically throwing the contact arm of the device to the ofi position upon the interruption of the current supplied to the motor, with which it is as sociated, irrespective of the position of the operating handle of the device.

A motor starter, as ordinarily constructed, is provided with a retracting spring by which the contact arm, to which a handle is ordinarily secured, may be automatically returned to the off position when the holding magnet, which is depended upon for holding the contact arm 1n the motor-running position, is deenergized. No means, however, is provided for preventing the attendant from manually holding the contact arm in the motor-running position, irrespective of the condition of the motor circuit. Should the supply of energy to the motor be temporarily interrupted when the contact arm is so held in its motor-running position, the motor is likely to be injured.

According to my present invention, I provide a contact arm which is independent of the operating handle lever except when current is being supplied to the motor. With this arrangement, the contact arm is returned to its off position whether the operating handle lever is retained in any other position or not, provided the supply of energy to the motor is interrupted.

Figure 1 of the accompanying drawings is a plan view of a controller embodying my invention, and Fig. 2 is asectional elevation on the line IIII of Fig. 1. Fig. 3 is a view corresponding to Fig. 1, but illustrating a modified structure which embodies my invention. Fig. 4 is a sectional elevation on the line IVIV of Fig. 3, and Figs. 5 and 6 are detail views, on a larger scale, of certain of the parts shown in the other figures.

Referring to Figs. 1 and 2 of the drawings, the structure here shown comprises a slab or base 1 of insulating material having a plurality of stationary contact members 2 secured thereto in an arc of a circle and a rod or shaft 3, the center line of which is perpendicular to the plane of the slab and passes through the center of curvature of the are above referred to; an electromagnet 4 comprising a cylindrical cup 5 of magnetizable material and a magnet coil 6, a contact arm 7 and an operating lever 8. The contact arm 7 is secured to a projection 9 upon the cup 5 and extends radially outward from the shaft 3 on which the cup is mounted. The length of the arm and its shape are such that its outer end is adapted to sweep over the contact members 2 when it is rotated about the shaft 3 as an axis.

The cup 5 is provided with a hollow cylindrical projection 10 which is centrally located and projects upwardly from the bottom of the cup, the coils 6 being located within the cup around the projection 10. The projection is fitted over the shaft 3 and a helical spring 11 is coiled about the shaft 3 and is located within the hollow projection, being secured at one end to the shaft and at the other to the cup.

The operating lever 8 is enlarged at its inner end to form a cup which is rotatably mounted on the shaft 3 and fits over the cup 5, and, at its outer end, it is provided with a handle grip 12. The operating handle is held in engagement with the surface of the cup by means of a spring 13, which is coiled about the outer end of the shaft 3 and is located between the enlargement or hub 14 thereof and the lever 8.

When the magnet winding 6 is energized, the walls of the magnetizable cup become magnetized, the magnetic circuit being completed through the walls of the projection 10 and through the enlarged portion of the operating lever 8, which is also composed of magnetizable material.

A latch 14: is pivotally mounted on a projection 15 upon the base 1 and is normally held against a stop 16, by means of a spring 17 The operating lever is provided with a downwardly projecting pin 18 which is so located as to be engaged by the latch 14- when the operating lever occupies its motor-running position.

The operation of'the device is as follows: Assuming that the contact arm 7 is retracted by the spring 11 to its off position, so that it engages a stop 19, and that the operating lever is located above it, if the oper ating lever is now rotated in a clockwise direction, the contact arm 7 will be carried with it, the retracting force exerted by the spring 11 being slight when the arms are in this position, and the friction produced by the spring 13 between the engaging surface of the lever and the cup being so pro portioned as to permit the operating lever to move the contact arm into engagement with the first of the series of contact members 2. As soon as the contact member 2 is engaged by the lever 7, the motor circuit is completed, from any suitable source, through the conductor 20, magnet winding 6, conductor 23, resistance 24, and conductor 25 to the opposite terminal of the source of energy, thus the magnet 1- is energized and the members 7 and 8 are magnetically held together so that, as the operating lever 8 is still fur ther rotated in a clockwise direction, the arm 7 successively engages the members 2 and short circuits the resistance 24. \Vhen the motor-running position is reached the arm 8 is held by the latch 14. As long as normal conditions exist, the parts will occupy the posit-ions indicated in the drawings, but, should the supply of energy be interrupted, the magnet 1 will of course be deenergized and the contact arm 7 will be forcibly returned to its off position by the spring 11, although the operating lever 8 will still be retained in the same position by the latch 14. In order to again start the motor, it is necessary to release lever 8 and return it to its off position in which the friction between the members 5 and 8 is sufficient to permit the two arms to move together. The motor may be stopped at will by simply releasing the latch 14, whereupon the spring 11 will throw both the arms 7 and 8 to the ofi position.

Referring to Figs. 3, 4t, 5 and 6 of the drawings, in which like parts are designated by the same reference characters as those used in the preceding figures, the magnet winding 6 is mounted on a core member 26 which is parallel to the shaft 3 and is lo cated at one side of it instead of being concentric with it. The contact arm 7 is secured to and is insulated from a member 27 of U shape which is pivotally mounted on the shaft 3 and carries the magnet winding 6 and the core members 26 and 28. The spring 11 is coiled about the shaft 3 and is secured at one end to the member 27 and at the other end to the shaft, so that it tends to retract the arm 7 to its 0& position in which it engages the stop 29. The operating lever 8 is provided with a projection 30 which extends outwardly from one arm of the member 27 and is provided with a pocket or recess 31 in which a small ball 32 is located. The bottom of the pocket 31 is provided with an opening which is slightly smaller in diameter than the ball 82 in order to permit it to extend through the projection 30 without becoming separated from the pocket. The ball 32 is pressed downwardly by a spring 33 which is located in the pocket and is held in compression by the cup 3 1. The core member 28 is secured to the outer arm of the member 27 and is provided with a hole 85 which extends axially through it. Its outer end is flush with the outer surface of the member 27 and is provided with a concavity which may be engaged by the ball 32 when the projection 30 is directly over the member 27. The core member is loosely supported by the inner arm of the member 27 and is provided with a hammer rod proj ection 36 which extends through a hole 35 in the member 28 and engages the ball 32. The arrangement of parts is such that when the magnet winding 6 is energized, the core member 26 approaches the member 28 and the projection 86 forces the ball 32 out of the concavity with which it engaged. The core member 26 is provided with a notch 20, as shown in Fig. 6, to be engaged by the inner end of a screw 26 which projects through the inner arm of the member 27 and limits the movement of the core member in one direction in order to prevent it from dropping down against the slab or base 1.

The operation of and the circuit connections for rheostat shown in Figs. 3, l, 5 and 6 are substantially the same as those already described in connection with Figs. 1 and 2.

I desire that structural modifications which do not depart from the spirit of my invention shall be included within its scope.

I claim as my invention:

1. A controller comprising a plurality of stationary contact members insulated from each other and arranged substantially in an arc of a. circle, a movable contact arm adapted to sweep over the stationary members, an operating handle lever independently pivoted upon the same axis as the contact arm, a spring tending to cause the arms to operate together and means, dependent upon predetermined conditions in the circuit governed by the controller, for locking the two arms together.

2. In a controller for electric motors, the combination with a slab or face plate, a plurality of contact members secured thereto substantially in an arc of a circle, a movable contact arm pivotally mounted upon the face plate and adapted to sweep over the stationary contact members, a spring for retracting the arm to its off position, an opcrating handle lever independently pivoted upon the same axis as the contact arm, yielding means for resisting the separation of the two arms, and electro-responsive means for locking the arms together.

3. In a controller for electric motors, the combination with a slab or face plate, a plurality of contact members secured thereto substantially in an arc of a circle, a movable contact arm pivotallymounted upon the face plate and adapted to sweep over the stationary contact members, a spring for retracting the arm to its ofi position, an operating handle lever independently pivoted upon the same axis as the contact arm, means for accentuating the position of either arm which corresponds to the position of the other, and electro-responsive means for predominating over the retracting spring to cause the arms to operate together.

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

FLETCHER D. HALLOCK.

\Vitnesses:

ALBERT VAN ZANDT, B. B. HINES.

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