US790541A - Controller for electric motors. - Google Patents

Description

PATENTED MAY 23, 1905.

W. J. WARDER, JR. CONTROLLER FOR ELEGTRIG MOTORS.

nrmoumn FILED SEPT. 26, 1904.

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wait 6 71/ [0'60 UNITED STATES Patented May 23, 1905.

PATENT OFFICE;

IVALTER J. IVARDER, JR, OF CHICAGO, ILLINOIS, ASSIGNOR TO IVESTERN ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

CONTROLLER FOR ELECTRIC MOTORS.

SPECIFICATION forming part of Letters Patent No. 790,541, dated May 23, 1905.

Application filed September 26, 1904:. Serial No. 225,914.

To rtZZ 1117110771 it may concern.-

Be it known that I, IVALTER J. WVARDER, J12, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Controllers for Electric Motors, of which the following is a full, clear, concise, and exact description.

My invention. is especially intended for use To in controllers used with motors which operate machine-tools or other machinery requiring variable speed, and comprises two main features:

First. The shaft which carries the main 1 5 drum. is combined with cam mechanism and the shaft of the reversing-drum in such manner that both drums may be rotated as required by means of the single handle of the main shaft. The construction is such that when. the main drum is brought to its off position the attendant by giving the handle a slight turn in a direction opposite to that required to operate the main drum causes the cam mechanism to give the reversing-drum 2 5 a quarter-revolution. The reversing-drum can only be operated when the handle is in its off position. Thus the machinist or attendant before beginning a particular kind or piece of work sets the controller for the direc- 0 tion of rotation required, after which the motor is started and run at various speeds by simply turning the main drum without liability of interfering with the reversing-drum, the direction of rotation being fixed until the 3 5 reversing-drum is moved, in the particular embodiment herein described, one quarter of a revolution.

Second. The special construction of the contact-fingers of the main drum and the 4 magnetic circuit to maintain the air-gap uniform with respect to all the lingers while the weight of the parts lifted in making their electrical contacts upon the drum is diminished. In addition. it may be mentioned that I do not 4 5 include the springs on which the contacts are mounted in the heavy currents, and thus avoid taking the temper out of such springs. The fingers may be said to be composite, each being provided with a path of non-magnetic material for the current and with a magnetic portion for carrying the flux. These two portions (the current-path and the flux-path) are insulated from one another.

My invention will be more readily understood by reference to the accompanying drawings, in which Figure 1 is a front elevation with the cover removed and portions broken away. Fig. 2 is a plan view of the same. Fig. 3 is a plan view with the top removed and portions broken away to show the features of my invention. Fig. 4 is a detail perspective view of one contact-finger, and Fig. 5 is a diagrammatic perspective view of the reversing mechamsm.

Within the containing-case, as shown in the drawings, is a shaft a, carrying the main drum, and a shaft 1), carrying the reversingdrum. Upon the shaft a, near the upper end of the same, is mounted a reversing-lever a, carrying a roller (7, which engages a lever e, loosely mounted upon shaft I). Pivotally mounted upon the under side of lever e is a spring-actuated pawl f, which engages a ratchetwheel g, keyed to shaft 6, which ratchet-wheel may be cast integral with the cam h. The lever 'i is mounted upon a lug cast upon the rear wall of the containing-case and is held in position by a spring 7r. This spring serves a twofold purpose, in that when the main shaft a is turned in a contra-clockwise direction the roll-carrying lever 0 moves the lever c in a clockwise direction, thus forcing the pawlf to engage the ratchet g, which being connected to the cam it, against which the roller is normally pressed, forces one of the arms of the cam into engagement with the spring-controlled lever and moves the same out of the path of said arm. As soon as the roller has been forced over the highest point of the opposing arm or projection of the cam the roller f of the lever t is forced by the contraction of the spring 75 against the cam to ro tate the same, and hence the shaft b,carrying the reversing-cylinder, a quarter-revolution.

The motor-armature terminals are thus re,

versed through the medium of the reversingdrum. The extent of the rotation of the shaft bis indicated bya pointer-fingermounted on the upper end of said shaft on the top of the case. The lever 6 would under ordinary circumstances maintain its normal position; but in order to prevent any accidental movement thereof a spring 6' is provided, which is connected by a hook to one end thereof and by similar means to the front of the cover of the containing-case, so that the finger Z of the lever e may never get into such a position as to permit the roller 61 to come behind said finger, and thus interfere with the operation of the reversing mechanism. The reversing-cylinder is thus readily rotated a quarter-revolution, or a ste ,b moving the handle 71. backward after it fias been brought into proper or off position.

Below the bifurcated lever c and rigidly mounted upon shaft 0. is the notched disk or star-wheel m, of usual construction and so placed as to register with the contact-blocks mounted upon the shell of the main drum p, said drum being located directly below said star-wheel and upon the same shaft.

I will now describe in detail the second feature of my invention.

The contact-fingers g g g g g are rigidly mounted upon an extension of the pole-piece 1* of electromagnet 1*, but insulated therefrom, said contact-fingers consisting each of a magnetic conducting-body s, referably of cast-iron, and a non-magnetic e ectrical conducting-strip 8, preferably brass, having a terminal connector at one end and at the other end a flexible ribbon s for the purpose of connecting the body portion 8 to the contact button i. The non magnetic springstrip t, securely mounted on the main body portion 8, (but preferably insulated therefrom,) serves as a support for the contact-button t. The tension of said spring-strip is adjusted by means of a setscrew t screwed throughthe non-magnetic piece 8, and passing through a hole in iron piece 8 is insulated therefrom. The wearing away of any of the contacts i will not change the length of the air-gap, since the magnetic air-gap is determined as to each of the fingers by the distance of the free end of iron piece 8 from the cylinder. There is thus obtained uniformity in density of flux at each of the fingers, insuring the blowing out of any arc that may be formed under all conditions of service. At the same time the current-carrying portion 8 of the finger is independent of the portion 8, that carries the magnetic flux, and hence these parts may be built with sole reference to the particular office that each is to serve that is to say, the current is provided with a circuit of the proper carrying capacity and resistance and the contact tis readily lifted by the underriding patch or contact-rib upon the cylinder. There is no liability of heating the brass spring t, which would impair its resiliency. The iron casting sis made of the size and shape required, and its position is not changed by any change in the electric circuit or by the Wearing away of the contact t.

My invention may be applied to controllers of various forms.

Having thus described my invention, I

claim as new and desire to secure by Letters Patent 1. In a controller for electric motors, the combination with the drum which forms a part of the magnetic circuit, of a polar extension 1" with a composite finger mounted there-. on, said finger consisting of a non-magnetic portion for carrying current, and a magnetic portion for carrying flux, said magnetic portion being adapted to maintain a fixed position with respect to the said drum.

.2. The combination with the main drum of a motor-controller, of an electromagnet and its polar extension 1", composite fingers mounted upon said polar extension, the magnetic portions 8 thereof being insulated from the non-magnetic portions 8 as to each of said fingers substantially as described.

3. The combination in a motor-controller, of main drum-fingers g g g g, each comprising a magnetic and a non-magnetic portion with insulation between the same, the latter being carried around the free end of the former by the connection 8 to the contact 23, substantially as described.

4. In a motorcontroller, the combination with the main drum and the shaft a thereof, of the reversing-drum and the shaft 1) thereof, and intermediate cam mechanism, the shaft a when brought to the off or disconnected position of the main drum being adapted to put the cam mechanism in action on giving the said drum a slight motion opposite to that required to operate the main drum, to give the reversing-drum a reversing rotation or movement.

5. The combination with the shaft a and the handle 10. for turning the same, of the lever c carried thereby, the shaft 1) of the re versing-drum for carrying the same, the lever e loosely mounted on said shaft 1), with which the roller cZ carried by lever c is adapted to engage, the ratchet-wheel g with which the spring-pawlf carried on lever e is adapted to engage, the cam h moving with wheel 9 and adapted when rotated to carry the shaft 6, and the spring-actuated leveri having the roller provided thereon to follow the surface of the cam; whereby on bringing the said handle to the off position, and giving the same motion opposite to that required to move the main drum when in service, the reversingdrum is rotated a step substantially as described.

6. The combination with the shaft a, of the shaft 6, the earn it and the spring-controlled lever i having the roller adapted to press against the cam-surface, and intermemy name this 27th day of August, A. D. diate spring-and-lever mechanism, whereby 1904. the shaft b may be rotated a step at a time on applying power to the shaft a to rotate WVALTER 5 the same a short distance when said shaft a, Witnesses:

has been brought to a given position. GEORGE P. BARTON,

In witness whereof I hereunto subscribe WV. H. VVARREN.

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