US519121A - Controlling device for electric motors - Google Patents

Description

(No Model.) 2 Sheets-Sheet 1.

P. B. HERDMAN.

CONTROLLING DEVICE FOR ELEOTRIG MOTORS. No. 519,121. Patented May 1, 1894.

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(No Model.) 2 Sheets-Sheet 2. F. E. HERDMAN.

CONTROLLING DEVIGE FOR ELECTRIC MOTORS.-

No. 519,121. Patented May 1,1894.

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UNITED STATES PATENT OFFICE.

FRANK E. HERDMAN, OF INDIANAPOLIS, INDIANA.

CONTROLLING DEVICE FOR ELECTRIC MOTORS.

SPECIFICATION forming part of Letters Patent No. 519,121, dated May 1, 1894.

Application filed July 19, 1892. Renewed January 11, 1894. Serial No. 49654:7- (No model.)

.To all whom it may concern:

Be it known that I, FRANK E. HERDMAN, a ci tlzen of the United States, residing at Indianapolis, county, of Marion, and State of Indiana, have invented a new and useful Improvement in Electric Motors, of which the following is a full, clear, and exact descrip tion, reference being had to the accompanying drawings, which form a part of this specification.

The objects of this invention are to give better contact and greater efficiency in the consumption of the current for the operation of electric motors in use with elevators or in any manner of use where they are subject to being continually stopped, started and reversed. One of the difficulties to be overcome, especially with elevators, is the great strain upon the main circuit and the central station when starting. Thus, the moment before the armature of the motor commences to revolve after the current is turned on the same, an excessive amount of current is liable to pass through it, causing a momentary strain upon the power supplying the current. As soon as the armature commences to revolve, this strain is gradually reduced, until the motor obtains its speed.

My invention consists in certain improved wiring and electric connection, so that excessive strength is given to the fields at the time the current is thrown on to the motor, and the armature thus revolves that much quicker, and also obtains its speed in much less time, than if the fields were not strengthened, thereby reducing the strain on the power station. Of course, this greater strength of the fields, if maintained, would prevent the motor from running at its full speed. Consequently, the strength of the fields is reduced as the motor increases its speed to the maximumat the same time afiording the means of reducing to the minimum the strain upon the power station in starting.

In the drawings-Figure 1 is a diagrammatical view. Fig. 2 is a diagrammatical view. Fig. 3 is a diagrammatical view. Fig. 4 is a face view of lever of Fig. 3. Fig. 5 is a plan view of lever of Fig. 3. Figs. 6, 7 and 8 are detail views of the switch roller.

M is the motor.

Ais the rheostat box. In this box is the wooden drum A, loose on the shaft a, having bearings a, (1. This drum has upon its face two plates, B and C. These plates are of peculiar shape and Wound around the drum in a peculiar manner. Thus the plate B has a solid portion 1) at one end, while at the other end it is formed into two portions, 1), b separated by a space. The plate 0, in a similar mannor, has at one end the solid portion 0, and at the other end the two portions 0', c separated by a space. These plates are wound around the drum in a peculiar manner, so that they cross one another. At their point of passing, the two plates are separated by an insulated strip.

Beneath the drum A, and in contact with the same, are the two brushes 3 and 4, one in contact with plate B, and the other in contact with plate 0.. The brush 3 is connected directly with the main circuit, the brush 4 being in direct electrical connection with the other pole of current supply, the field of the motor being also in direct electrical connection with the source of current supply. In contact with the top of the cylinder A are the brushes 5, 5 and 6, 6. The brushes 6, 6', are in electrical connection with the solenoid D. Brush 5 is in electrical connection with the contact 30; the other brush 5' is. in electrical connection with the armature of the motor.

E is an arm connected at one end to the.

solenoid core and at the other end to a dash pot F.

G is an arm connected to the arm E, and carrying a brush g.

H are the resistances, and the arm G from the point g is in electrical connection with the armature of the motor and has brush 9',

so that through the resistances and arm G,

brush 5 is in electrical connection with the armature of the motor. The fields of the motor being excited in the usual way, with the wiring for the best results for its maximum speed and connected to the main circuit, as hereinbefore described; there are placed, in addition to this arrangement, on the outside of the regular coils, or on a separate spool in the field magnet, a succession of coils, K, K, K K, 850. Each individual coil of these coils is brought to the surface and connected on one side with one pole of the main circuit,

and on the other side with its individual contacts, It, S, T. The contact Q is connected with the remaining pole of the main circuit. These contacts are so arranged that contact Q extends beyond the limit of contacts It, S,- and T, while contacts R, S and T are of different lengths, both contact Q and contacts R, S and T are in line of movement of arm G, and these contacts R, S and T are so arranged that as the arm G passes over the rheostat face, it cuts out one of these contacts at a time. To the arm G is attached a brush J, which passes over the contacts and is insulated from the arm G. Thus when the switch is operated to admit the current and the solenoid electrified, the arm G travels over the rheostat. As the arm G moves, first contact R is cut out, as it passes beyond said contact, then contact S, and finally contact T. Thus, as the arm G travels over the rheostat face, one coil at a time of the entire coils K, K, K &c., is cut out of the field circuit, thereby reducing it. In this way, at the starting, the fields are given greater strength, thus giving the armature greater power of starting, with less strain on the central station.

Instead of connecting the armature directly with the lever G, I can connect it through a solenoid 25 (see Fig. 2), the core of which is provided with a trip 26, which works in a series of teeth on a wheel 27, attached to the arm G and turning 011 the same pivot as said arm. Nhen the current reaches the proper limit, to prevent strain on the motor, this solenoid 26 will draw in the core and raise the trip 26 until it is in contact with the teeth of wheel 27, thereby preventing any further movement of the arm G, thus in consequence retaining a certain number of coils K, K K in circuit, and also retainingacertain amount of resistance in the armature circuit. when the speed of the motor increases so as to reduce the amount of current passing through this solenoid to the armature to within the maximum amount, then the core drops, releasing the trip from the teeth and allowing the arm g to continue its movement to the right, and cutting the resistances out of the armature circuit, also cutting the additional strength out of the fields. If the current passing through becomes excessive, the solenoid would at once act and again check the movement, thereby preventing an excessive amount of current passing. The brush J, instead of being carried by the arm G, may be carried by an independent ar (see Figs. 3, t and 5). This arm 32 is pivoted to the arm E at the same place that the arm G is pivoted (see Fig. 5) and has the toothed wheel 27, in the teeth of which the trip 26 works. A weight 33 is attached to arm 32 and said arm has a projection 34; so that said arm 32 and arm G may work independently, the weight 33 moving said arm, and the trip 26 and solenoid 25 regulating the movement of said arm. When the current is turned off, the

arm G, on its return movement, strikes the projection Set, carrying the arm back with 1t.

Having now fully described my invention, what I claim, and desire to protect by Letters Patent, is

1. In combination, a source oE current supply, a switch, electrical connection between said switch and the source of current supply, a rheostat, electrical connection between said rheostat and switch, a solenoid, electrical connection between said solenoid and switch, an arm operated by the core of said solenoid and adapted to travel over said rheostat, a motor,

electrical connection between the source of current supply and field coils, electrical connection between the armature of motor and switch, and electrical connection between said armature and arm operated by solenoid, coils around the field magnets, contacts to which said coils are separately connected, said contacts being of different length, said coils also connected with the main circuit, and a contact connected with the other pole of the main circuit, and an arm adapted to pass over said contacts.

2. In combination a source of current supply, a switch, electrical connection between said switch and the source of current supply, resistances, electrical connection between said resistances and switch, a solenoid, electrical connection between said solenoid and switch, an arm operated by the core of said solenoid and adapted to travel over said resistances, a solenoid in electrical connection with said arm, a motor, electrical connection between the source of current supply and field coils electrical connection between the armature of the motor and the switch, electrical connection between said armature and solenoid in electrical connection with the arm, coils around the field magnets, contacts to which said coils are separately connected, said contacts being of different length, said coils also connected with the main circuit, a contact connected with the other pole of the main circuit, an arm adapted to pass over said contacts, a toothed wheel on said arm, a trip attached to the core of the solenoid in electrical connection with the armature, said trip being adapted to work in the teeth of said toothed wheel.

3. In combination, a source of current sup ply, resistances electrical connection between said resistances and the source of current supply, an arm adapted to travel over said resistances, a motor, electrical connection between the source of current supply and the field coils, electrical connection between the armature of the motor and the source of current supply, electrical connection between said armature and said arm, coils around the field magnets, contacts to which said coils are separately connected, said contacts bein g of different length, said coils also connected with the main circuit and a contact connected with the other pole of the main cir- ICO cuit and an arm adapted to pass over said contacts.

4:. In combination, a source of current supply, resistances electrical connectionbetween 5 said resistance and the source of current supply, an arm adapted to travel over said resistance, a solenoid in electrical connection with said arm, a motor electrical connection between the source of current supply and the 10 field coils, electrical connection between the armature of the motor and the switch electrical connection between said armature and solenoid in electrical connection with the arm, coils around the field magnets, contacts 15 to which said coils are separately connected,

Witnesses:

W. L. ROBINSON, W. V. MARTIN.

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