US382715A - Switching device for electric motors - Google Patents

Description

3 SheetsSheet 1.

(No Model.) I 8 v R. H. MATHER.

SWITGHING DEVICE FOR ELEGTRIG MOTORS. v No 882,715. 8 I Patented May 15, 1888.

(No Model.) 3 SheefiSSheet, 2.

R. H. MATHER.

SWITCHING DBVIOE FOR ELECTRIC MOTORS. N0. 882,715; Patented May. 15, 1888.

(No Model.) 3 Sheets-Sheet a.

ERMA-T EE."

SWITCHING DEVICE FOR'ELEGTRIG MOTORS.

No. 382,715. Patented May 15; 1888-.

UNITED STATES PATENT Crric e.

RICHARD H. MATHER, OF WINDSOR, CONNECTICUT.

SWITCHING DEVICE FOR ELECTRIC MOTORS.

SPECIFICATION forming part of Letters Patent No. 382,715, dated May 15,1888.

Application filed February 19, 1887. Serial No. 228,251. (No model.)

To a whom it may concern.-

Be it known that I, Brennan H. MATHER, of Windsor, in Hartford county, Connecticut, have invented certain new and useful Improvements in Switching Devices for Electric Motors, which are described in the following specification, and illustrated by the accompanying drawings.

My invention-is designed to be used in connection with an electric motor, particularly a series-wound motor, and an electric circuit of constant current, for the purpose of introducing such motor into such circuit gradually and without danger of sparking or of interrupting the constancy of that current, and for the purpose of cutting said motor out of said circuit in a gradual and convenient manner. These objects I accomplish by means of a rheostat which is connected with the main circuit and in parallel with the motor, and by means of certain contacts and connections which are adapted to introduce and to cutout successive portions of the rheostat and at the same time to maintain the main-circuit connections of said motor.

The best manner in which I have contemplated applying the principle of my invention is shown in said drawings, in which- Figure 1 is a front view of my invention. Fig. 2 is a section on x m of Fig. 1. Fig. 3 is a section on y y of Fig. 1. Fig. 4 is a detail. Fig. 5 is a back view of my inventi0n,the back side of the resistance-box being removed; and Fig. 6 is a front view of said resistance-box and switch connected with a series-wound electric motor.

In the views,the numeral 1 denotes the front side or cap of a wooden box containing a rheostat, which is of any ordinary and convenient construction.

The numerals 2 to 15, inclusive, in Fig. 5 indicate the several resistance'coils of said rheostat, which are connected in the usual manner with each other, and with a number of brass studs or other contacts, 16 to 30, in elusive, which pass through cap 1 and are arranged in the arc of a circle, as seen in Figs. 1 and 5. The aggregate resistance of said coils is greatly in excess of that of the electric mo tor which is to be used in connection therewith. Upon the face of cap 1, adjacent to in either direction.

said studs, but not in connection therewith, is acurved contact plate having the form of a segment of a flat ring,which is concentric with said are. This plate is separated by a crosscut into two unequal parts, 31 and 32. Holes 37 and 38 pass through plates 31 and 32. At the common center of said are and ring, upon cap 1, is pivoted an arm or switchfinger, 33, which is seen in detail in Fig. 3. This arm is provided with a brush, 34, one end ofwhich, being wider than the space between any two of said studs, which are adjacent to each other, is adapted to make successive contacts with all said studs, while the other end of said brush is constantly in contact with one or the other of said plates 31 and 32. Stop-pins 39 and 40 (seen in Fig. 1) are so placed as to prevent arm 33 from passing beyond said studs The free end of said arm is provided with a spring-seated pin, 35, one end of which is provided with a finger-piece, 36, while the other end of the same is adapted to press into holes 37 and 38 when arm 33 is deflected to its extreme positions.

Just under hole 37 is a hole, 41, extending through cap 1. cap,near hole 41,is mounted a cut-out magnet, 42, which is shown in Figs. 3, 4, and 5. This magnet, which is .wound in the usual manner with helix 43, is provided with a-spring-seated armature, 44, which is armed with a detent or tooth, 45. This tooth, as seen in Fig. 3, is adapted to engage an insulated spring, 46, which carries a contact, 47, adjacent to con tact 48, and is provided with a stem, 49,which is partly within hole 41. Binding-posts and 51 are the terminals of the instrument.- The signs andin Fig. 6 may be regarded as the positive and negative terminals, respectively, of an electric generator. p

Such being the elements of my invention, the appropriate electrical connections not already indicated are as follows: The positive terminal of said generator is connected with said motor by wire 52 and with terminal 51 by wire 53. Stud 16 is connected with terminal 51 by wire 54 and with contact 48 by wire 55. Contact 47 is connected with plate 31 by wire 56. Terminal50 is connected with the negative side of said generator by wire 57, with plate 31 by wire 58, and with said motor Upon the under side of this duced.

by wire 63. Helix 43 is connected by shuntwires 59 and 60 with wires and 56, respectively. Stud 16 is connected with resistancecoil 2 by wire 61 and stud 30 with coil 15 by wire 62.

The remaining particulars of the construction and connection of this invention will sufficiently appear from its mode of operation, which is now to be explained.

\Vhen arm 33 occupies its extreme position of contact with pin 39, brush 34 makes contact with stud l6 and plate 31, while pin 35, entering hole 37, as seen in Fig. 3, looks the switch closed. The current then passes from the positive side of the generator successively through wires 53 and 54, stud l6, brush 34,

plate 31, wires 58 and 57 to the negative side of said generator, and the motor is inactive. Vheu arm 33 is in the extreme position of contact with pin 40, the poiutof the springseated pin 35 is held in hole 38, and thus said armis locked in that position. Brush 34 then rests upon stud 30 and plate 32, and the current passes from terminal to terminal of said generator by the way of wire 52, said motor, and wires 63 and 57. At the same time an insignificant portion of the current, which is supplied by the generator passes from terminal by wires 53, 54, 55, and 59, helix 43, wires and 56, plate 31, and wire 58 to terminal 50. When arm 30 occupies an intermediate position, as in Figs. 2 and 5, one end of brush 34 rests upon plate 31, while the other end of the same rests upon one or two of said studs. In this position of affairs the distribution of current is in two courses. One part of the current passes through the motor by way of wires 52, 63, and 57, while the other part of the same passes through a portion of said resistancecoils by the way of wires 53 54, brush 34, plate 31, and wires 58 and 57.

Assuming the switch to be in the position first above described, it it be desired to intro duce said motor into circuit with the generator, said arm is unlocked from its position of contact with pin 39 by manipulation of pin 35, and is slowly deflected by hand toward stoppin 40. The resistances in the rheostat-circuit cause the motor to receive a slight current when the described motion of arm 33 begins. As the motion continues, a gradually-increasing number of said resistances is brought into circuit, and the motor is more and more energized until all said resistances are intro- Then the connection between arm 33 and plate 31 is broken, and the whole current passes through the motor. lVhen arm 33 encounters pin 40, the rheostat is cut out of circuit, and pin 35, entering the hole 38, looks the switch, as above described. By unlocking the switch and carrying arm 33 back to the position first above mentioned the switch is closed, and the current is permitted to pass in t-hefirst-mentioned course through wires 53 and 54, stud 16, brush 34, plate 31, and wires 58 and 57.

In case of any accident, causing an interruption of current through the motor, the increase of current through helix 43, which is arranged in parallel with the motor, causes armature 44 to withdraw tooth 45 from plate 47, and the latter, being thus released, is carried by the elasticity of spring 46 to contact with plate 48. The motor is thus short circuited and the current passes between terminals 51 and 50 by wires 54 and 55, plates 48 and 47, and wires 56 and 58, and continues so to do until plates 47 and 48 are separated. Such separation occurs when arm 33 is returned to the position shown in Fig. 3, being produced by the pressure of pin 35 upon the end of stem 49. The cutout switch is then locked in its original position by the action of the spring-seated armature 45, and the motor remains short-circuited through brush 34 until the arm 33 is again deflected toward pin 40.

Disclaiming, for the purposes of this case, all things which are shown and claimed in my application, Serial No. 225,887, which was filed January 29, 1887, for a patent upon switches for electric motors, I claim as my invention-- 1. An electric circuit, aseries-wound motor in said circuit, a rheostat which is provided with a series of contact-points and is con nected with said circuitatone sideof said motor, a conductive plate which is connected with said circuit at the other side of said motor, a switch-finger which is adapted to make successive contacts with said contact-points and to make and break contact with said plate, in combination with an automatic cutout which is arranged as a shunt about said rheostat and motor, substantially as and for the purpose specified.

2. An electric motor, an automatic cut-out, a rheostat, and a manual switch which is adapted to manipulate said rheostat, in combination with spring mechanism which is carried by the switch-arm and is adapted to open said cut-out whenever said arm is carried to a predetermined position, substantially as and for the purpose specified.

3. An electric motor and a rheostat,in combination with a manual switch which has a movable switclrarm and is adapted to operate said rheostat, a spring-seated stop-pin which is carried by said arm, an automatic cut out which is provided with spring-contact, and an intermediate stem whereby motion is communicated from said stop-pin to said spring-contact, substantially as and for the purpose specified.

In testimony whereofl havehereunto set my name in the presence of two witnesses.

RICHARD H. MATHER.

WVitnesses:

W. M. DYORKMAN, WVILLARD EDDY.

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