US589433A - Ellen hirst adminis - Google Patents

Description

(No Model.)

R. B. HIE ST, Decd.

E. Hmsr, Administratrix. STARTING BOX FOR ELECTRIC MOTORS.

No. 589,433. Patented Sept. 7,1897. FIG. I.

FIG. 3.

WITNESSES: INVENTOR: Z T {M I By his Azzorneys.

W@.@rnw g UNITED STATES PATENT OFFICE.

ROBERT I IIIRST, OF BROOKLYN, NEW YORK; ELLEN IIIRST ADMINIS- TRATRIX OF SAID ROBERT I). IIIRST, DECEASED.

STARTING-BOX FOR ELECTRIC MOTORS.

SPECIFICATION forming part of Letters Patent No. 589,433, dated September '7, 1897. Application filed July 3, 1897. Serial No. 643,470. (No 1110(l6l.l

To all whom it may concern:

Beit known that I, ROBERT B. IIIRs'r, a citizen of the United States, residin gin Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in Starting-Boxes for Electromotors, of which the following is a specification.

This invention provides an improved starting-box for electromotors designed to avoid the necessity of providing an external switch for breaking the main circuit in order to stop the motor.

My improved starting box enables both the starting and stopping of the motor to be e1":- fected by the manipulation of the same handle or lever.

My invention is also applicable to controllers for electromotors.

I employ any ordinary resistance-box having a controlling handle or lever serving as the switch-arm for making connection with one or other of the resistance-contacts. I provide said boX with a double-pole switch,

the fixed leaves or members of which are connected to the circuit-mains, while the movable leaves or members are connected to move together, are provided with a spring for drawing them to the open position, and are arranged to be displaced by the resistanceboX lever to bring them to the closed position in the act of starting the motor. I provide the usual retaining-magnet or shuntmagnet for holding said switch closed, and in the shunt-circuit of said magnet I provide any usual overload-magnet adapted when eX- cited beyond the normal by an excessive current to attract its armature and thereby break said shunt-circuit, so as to open the switch, break the main circuit, and stop the motor. In addition I provide any suitable means operated by said lever for breaking the circuit of said retaining-magnet in order to enable the operator to stop the motor at will.

Figure 1 of the accompanying drawings is an. elevation or face view of my improved starting-box, the circuit connections being shown in diagram. Fig. 2- 'is a sectional elevation of the overload-magnet. Fig. 3 is an elevation showing a modified arrangement.

Fig. a is a face view showing a modification of Fig. 1.

Let A designate a resistance-box of any suitable construction having contacts a a and resistances or coils between them (inclicated diagrammatically at b b.) The usual lever B is arranged to move over the contacts in order to throw more or less resistance into circuit.

M designates the motor to be controlled, its armature being connected in a circuit 0 and its field-magnet coils in a circuit (1. Conveniently arranged on the resistance-box is a double-pole switch O O of any usual or suitable construction for closing or breaking the main circuit. I11 the construction shown this is a knife-switch, the arms O and O being pivoted at e and 6, respectively, and connected by an insulating-bar f, constituting a parallel-motion device for forcing the two arms to move together. When in the position shown in full lines, the switch-arms enter between the leaves of the fixed members g g, which connect with binding-posts 71 7t, to which the circuit-mains are joined.

The switch O O carries an armature 1 which when the switch is in the closed position comes into contact with a retaining-magnet D, the attraction of which holds the switch closed against the tension of a spring E, which strives constantly to open it. This spring E may be arranged in any suitable way, preferably by coiling it around one of the posts 6 e, but for clearness I have shown it as a tensile helical spring.

The magnet D is a shunt-magnet connected between the pivotal posts 6 e by means of a shunt circuit orloop 10 10. (Shown in dotted lines.) This shun t-circuit is controlled by an overload1nagnetF of any ordinary construction, being usually a series magnet connected in the main circuit and acting as a relay which normally holds the shunt 1O closed, but upon the passage of an abnormal current its armature is attracted and breaks the shunt. In the construction shown its armature j has a retracting-sprin g 7.2, which presses it strongly against a fixed but adjustable contact-screw t.

The circuit connections extend from binding-post 7L through switch members g and G to post c. Here the circuit divides, one branch passing through the field magnet coils of the motor and the other branch passing through the resistance-box to the armature. The field connection is by wire ll to binding-post 12, thence by wire cZ through the field to binding-post 13 and by wire 14: to post 0 and by switch members 0 and g to the opposite binding-post h. The armature connection is from post 0 by wire 15 to the pivot of lever 13, thence through this lever to any contact a, on which it may rest, and through any of the intervening resistance-coils Z) Z) to the final contact a, thence through the coil of overload-magnet F and by wire 10 to binding-post 1'7, and thence by wire 0 through the armature to binding-post l3, and out as before.

The lever B is arranged in any relation with the switch 0 C, by which the movement of the lever to cut in all the resistance is made effective to throw the switch to the closed circuit position, thereby starting the motor. I may arrange the parallel barf or any other part of the switch in the path of the lever, but preferably I have provided a pin or projection m, which projects into the path of the lever.

\Vhen the motor is at rest, the switch is in the position shown in dotted lines, and the lever may be preferably in mid-position. To start the motor, the lever is thrown over to the position shown in full lines, and in so doing it strikes the pin on and throws the switch over to its closed position, while at the same time the lever cuts in all the resistance of the box in circuit with the armature. The motor then starts, and as it gains speed the operator gradually cuts out resistance by moving the lever B in the contrary direction, until finally at full speed it stands upon the terminal contact a. The switch is not drawn back by the tension of its spring E, but is held by the attraction of the shuntmagnet D. The motor will now run continuously until stopped in one or other of three ways, either, first, by the occurrence of an overload, or, second, by a cessation of current 011 the main circuit, or, third, by the act of the operator when he desires to stop it. In the first case the magnet F becomes overexeited and attracts its arm atrn-e,thereby breaking the shunt-circuit 10 at Z, so that magnet D is demagnetized and lets go the switch, which is instantly thrown over by the spring E to the open position shown in dotted lines, therebybreaking the circuit and stopping the motor. In the second case the magnet I) is demagnetized by the drop in voltage. In the third case the shunt-circuit 10 is broken by a movement imparted to the lever B in the manner which I will now describe.

I provide any suitable means to be operated by a movement of the lever for breaking the circuit of the retaining-magnet. The preferred means is that best shown in Fig. 2, by which the lever 1 acts mechanicallyupon the armature of the magnet F to pull it away from the screw Z, to the same effect as though the magnet F were overcharged. Connected to the armature is an arm or slide 2), having a hooked end p, with which end cooperates a stiff spring q, carried by the lever B. By moving the lever 13 to the position of full speed (shown in dotted lines in Fig.1 and in full lines in Fig. 2) the spring (1 moves over the beveled end 1) and snaps past it to the position shown in Fig. 2. In so doing its thrust exerted against the slidep presses it into firmer contact with the screw Z. \Vhen the operator desires to stop the motor, he moves the lever B in the contrary direction, whereupon its springarm q catches against the abrupt end of the hook p and displaces the slide 1), pulling it out of contact with the screw Z, and thereby breaking the shunt-circuit 10, with the effect of demagnetizing the retaining-magnet, releasing the switch, and stopping the motor. To the same effect I may introduce a separate circuit-breaker, as shown in Fig. 3, where a leaf-sprin g g presses against a stop-screw Z, both being in the circuit 10 and constituting a circuit-breaker. The spring q projects up into the path of the spring-arm (1 of the lever 13, which, moving toward the position shown in dotted lines, snaps past the spring q without impairing its contact with the screw Z, but on the return movement the spring-arm q presses the spring q away from the screw and breaks the circuit. Home with either of these construc tions the operator in order to stop the motor has only after having carried the lever to its extreme position to displace it slightly in the contrary direction. Ile should not move it far enough to displace the switch from its open position.

In case it is desired to control the speed of the motor by introducing more or less resistance for the purpose of varying the current which traverses its armature the mechanical circuit-breaker, which is operated by the lever B, has only to be placed in an intermediate position instead of at the extreme position, as shown, for example, in Fig. 4:. In this figure the construction is the same as already described, except that the overloadmagnet F,with the mechanical circuit-breaker shown in Fig. 2, is arranged, for example, midway of the row of resistance-contacts a a, the contact a in this case not being the final contact, but one of a series of contacts a a a, &c., whereby the resistance is varied according to the manner of controllers for electro motors.

My invention enables the motor to be both started and stopped by manipulating the lever of the starting-box and avoids the necessity of the outside double-pole switch heretofore required.

My invention is not limited to the exact arrangement of parts shown and heroin described, it being understood that the switch may be differently arranged with relation to IIC the lever and that any suitable mechanical construction or connection may be adopted for causing the movement of the lever to the starting position to displace the switch to the closed position. This may be accomplished either directly, as shown, or by some indirect mechanical connection. Neither is my invention limited to the exact details of construction of the switch or other elements of the device, as my invention is applicable with other constructions of switches, and in other respects is open to considerable modification in mechanical or structural details so long as the essential features of my invention are not departed from.

I claim as my invention 1. The combination with a resistance-box and its lever of a switch controlling the main circuit, movable to closed position by said lever, a spring tending to open said switch, a retaining-magnet adapted when excited to hold said switch closed, and means operated by said lever forbreaking the circuit of said magnet to release said switch.

2. The combination with a resistance-box and its lever of a switch controlling the main circuit, movable to closed position by said lever, a spring tending to open said switch, a retaining-magnet adapted when excited to hold said switch closed, an overload-magnet adapted when excited beyond the normal to break the circuit of said retaining-magnet, and means operated by said lever for breaking said circuit to release said switch.

The combination with a resistance-box and its lever of a switch controlling the main circuit, movable to closed position by said lever, a spring tending to open said switch,

a retaininganagnet adapted when excited to hold said switch closed, an overload-magnet adapted when excited beyond the normal to attract its armature to break the circuit of said retaining-magnet, and a mechanical connection between said overload-magnet and said lever, whereby the movement of said lever acts upon said armature to break the circuit of said retaining-magnet.

4. The combination with a resistance-box and its lever, of a double-pole switch controlling the connection of the respective circuitmains, with the resistances and motor movable to closed position by said lever, a spring tending to open said switch, a retaining-magnet adapted when excited to hold said switch closed, and means for breaking the circuit of said magnet to release said switch whereby the motor is controlled solely by the resistance-box switch.

5. The combination with a resistance-box and its lever, of a double-pole switch controlling the circuit-mains, constructed with movable arms or members C C turning around separate pivot-posts c c, with an insulating parallel barf connecting them, an armature carried by said bar, a retaining-magnet arranged to attract said armature, a spring for throwing said switch open, and means for breaking the circuit of said magnet to release said switch.

In witness whereof I have hereunto signed my name in the presence of two subscribing witnesses.

ROBERT B. IIIRST. lVitnesses:

ARTHUR O. FRASER, FRED WHITE.

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