US913437A - Automatic starter for continuous-current electromotors. - Google Patents

Description

G. A. SGHOELLER & H. SUNDHAUSEN.

AUTOMATIC STARTER FOR CONTINUOUS GURRENT ELEGTROMOTORS.

APPLICATION FILED MAR. 12, 1907.

91 3,437. Patented Feuzs, 1909.

I J V W W "mama? I {12/ JCQOU, 1 an UNITED STATES PATENT OFFICE.

GUSTAV A. SOHOELLER, OF MULHEIM-ON-THE-BUHR, AND HERMANN SUNDHAUSEN, OF ESSEN-ON-THE-RUHR, GERMANY, ASSIGNORS TO FRIED. KRUPP AKTIENGESELLSCHAF-T,

OF ESSEN-ON-THE-RUHR, GERMANY.

AUTOMATIC STARTER FOR CONTINUOUS-CURRENT ELEGTROMOTORS Specification of Letters Patent.

- Patented Feb. 23, 1909.

' Application filed March 12, 1907. Serial No. 362,072.

To all/whom it may concern:

Be it known-that we, GUSTAV A. SoHoEL- LER, residing at 2 Gustavstrasse, Mii-lheimon-the-Ruhr,Germany, and HERMANN SUND- HAUSEN, residing at 43 Riittenscheiderstrasse, Essen-on-the-Ruhr, Germany, both subjects of the Emperor of Germany, have invented a certain new and useful Improvement in Automatic Starters for Continuous- Current Electromotors, of which the following is a specification.

The present invention relates to an automatic starter for direct-current. electromotors.

An object of the invention is to provide a starter in which the current strength may be as hi h as desired and which may be regulated y changing the tension of a spring.

A further object is to provide a starter which insures the motor against overload without interrupting the running.

Other and further objects will appear in t following description and will be more particularly pointed out in the appended claims. 7 1

In the drawings :-Figure 1 is a diagrammatical view-of the invention, the starter be ing in the position of rest.' Fig. 2 is a view of the contacts-in the solenoid circuit, said contacts being spaced apart, and Fig. 3 is a view of the solenoid-circuit contacts, closed.

A are the electric mains or line wires to which the armature or main circuit C of the electro-motor D can be connected through the medium of the switch B and the contacts c, 0 In the armature or main circuit Cthe starting resistances W, W W and W and the maximum current operated means or a solenoid E are inserted. The armature e of the solenoid E is provided with two contacts 6 and e which are insulated from each other and from the armature. A lever F, which is under the action of aspring G of regulable tension by the screw 9 tends to hold the armature e, of he solenoid in the position shown in the i in which'the contact 6 through drawin "CBHQCtlOIl of the contacts h and 0 acts as switch to connect to the armature or menu .rcuit, a short circuit H extending parallel he starting resistances. In this position.

the armature e, the motor is, therefore, in TClllil with the mains and the reslstance 1s out.

J is the main starting solenoid which forms means for gradually-cutting-out' the resistance. The armature a" of this solenoid carries a contact or switch 2' which, when the armature moves, is successively brought into contact with the contacts a, a a a and u of the starting resistances, that is to say, it can successively short-circuit or cut out the several resistances. The armature a" carriesan extension i guided by rollers' K, and its movement can be braked by means manner that, when the circuit is closed, the

contact can move a little without leaving the contact m (as for instance a spring-contact, a plunger-contact or a sliding contact).

In that position of the armature e which isshown in the drawing, the contacts m and e do not contact and the shunt circuit M is, therefore, open.

When the armature ormain circuit C is connected to the mains by meansof the switch B, the current passes from the contact a through the coil of the maximum current solenoid or electro-magnet E, to the contact 0 thence through the contacts e h the shunt circuit H and the armature of the motor D to the contact 0 The motor is, therefore, connected to the mains without starting resistances. counter electro-motive force in the motor, the current strength in the armature circuit increases immediately after the -motor is switched in. As soon as the current strength Due to the lack of a has reached the amount permissiblefor the running of the motor, that is to say, as soon as it has increased so much that the ma gnetic 'force acting on the armature c of the solenoid E can overcome the resistance of the lever F, which is under the action of the spring G, the armature e of the solenoid E is attracted against the action of the spring The shunt circuit H is then first disconnected-from the armature circuit C so that the entire current must pass through without comingout of tacts e m enter into 'contact with eachother and close the shunt circuit M of the starting solenoid, which exerts a pull on its armature i, which, however, at first is not strong enough to overcome the braking action of the lever F. .In the meantime, the

motor hasbeen set in motion. When the speed ofrotation of the motor increases,

the counter electro motive force of the. motor increases, while at the same time the current strength in the armature or main circuit decreases. The attracting force of the maximum current solenoid E decreases and the braking force of the lever]? becomes correspondingly. smaller. In spite of the decrease in current strength, the shunt circuit M remains closed because as aforesaid, the contact' 6 can move a short distance tact m 1 The u ward movement of the armature e is reall cause, as soon as the attraction of the maximum solenoid E decreases, to become equal to the opposing pulling force of the spring G, the pressure or friction between the cam f and the extension i becomes equal to nothing. When the friction reaches a certain amount, the attraction of the starting solenoid J overcomes the braking action of the lever F and thearmature a" commences to move and short-circuit the first step of the starting resistance. .The cur-' rent stren h in the armature or main circuit then immediately increases. This proceeding is repeated until all the starting resistances are short-circuited and the motor has obtained its normal speed. As the currentstrength has then been lowered to operating current strength and'a newcurrent shock does not" any longer take'place, the pressure, which the lever F effects on the armature e due to the action of the G, overcomes the attraction of the maxrmum current solenoid and brings the contact '6 of the armature into contact with the contacts 71. and 0 thereby connecting the circuit H to the armature circuit C. At the same time the shunt circuit M of the starting solenoid is interrupted due to the removal .of the contact e from the contact m (Figs. 2 and 3) and'the cam f of the lever F recedes from the armature a" which consequently drops down into its original position shown in the drawing. a The current now takes the same course as immediately upon the switching in of the motor.

The above-described starter presents the contact with "the con-I y practically equal to nothing, be-

I advantage that the current strength for. starting the motor can be selected as high as desired and can be regulated by changing the tension of the spring G. Moreover, the

starter insures the motor against overload without efl'ectingi'a stopping of the operation in case of overload, as is the case with lead safety fuses. As soon as the current strength,:which increases due to overloading the motor, has reached the amount of the starting current strength, the maximum current solenoid again enters into operation and switches in the starting resistance in front of the armature of the motor. Simultaneously with this, the starting solenoid is switched in.- When the overload "has been removed,

the speed of rotation of the motor is again. automatically brought to its normal amount in the aforesaid manner through the shortcircuiting or cutting out of the resistances. As the starting solenoid is without current after the starting of the motor has been eflected and as the maximum current solen-.,

oid; presents only a slight resistance, the starter uses onl little energy and is, therefore, economic Having thus "described our invention,

what we claim as new therein and desire to secure byLetters Patent is:

1. In a starter for continuous current electro motors, the combination withthe resistance, of a maximum current o erated means throwing in the resistance," an means gradually cutting out the said resistance, and controlled by the maximum current operated means.

2. In a starter for continuous currentelectro motors, the combination with the resist ances, of a shunt about the same a maximum current solenoid controlling Sflld' shunt cir-, cuit, and a starting solenoid for cutting out the resistances, having its circuit closed by the maximum current solenoid.

3. In an automatic starter for continuous current electric motors, the combination with the main circuit and the resistances-in the main circuit, of a shunt circuit about the resistance's, a solenoid operated to cut out the shunt circuit upon a maximum current in the main circuit, a cut out'for the resistances, a solenoid operating said out out and in shunt with the main circuit, and connection between the main current solenoid and the shuntcircuit of the other solenoid, to throw cur-rent electric motors, the combination w the main circuit, and resistance therein, a

' shunt circuit about the resistance, of a maximum current solenoid constructed to cut out 'the shunt circuit to cause the full current to pass through the resistance, a starting solenoid, a circuit for the starting solenoid closed when the maximum current solenoid attracts its armature, and broken when the latter solenoid releases its armature, and means ance, controlled by the maximum current operated means.

7. In an automatic starter for continuous current electric motors, the combination with the-main circuit and the resistance therein, of a maximum current solenoid, a starting solenoid controlled by the maximum current solenoid and cutting out the resistance, and a brake for the armature of the starting so lenoid, controlled by the maximum current solenoid. v v a 8. In an automatic starter for continuous current electric motors, the combination with the main circuit and the resistance therein,

of a maximum current solenoid, a starting solenoid controlled by the maximum current solenoid and cutting' out the resistance, a

.brake for the armature, of the starting" solenoid, controlled by the maximum current solenoid, and a shunt circuit'about theresistance, closed b the maximum current solenoid when it 1s in its inoperative position.

The foregoing specification signed at Dusseldorf, Germany, this sixteenth day of February, 1907.

GUSTAV A'. SOHOELLER. I HE-RMANN SUNDHAUSEN.

In presence of M. ENGELS, ALFRED POHLMEYER.

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