US595803A

US595803A - Samuel l

Info

Publication number: US595803A
Authority: US
Publication date: 1897-12-21
Anticipated expiration: 1914-12-21

Description

(No Model.) S. L. BARRIETT.

AUTOMATIC SWITCH FOR ELECTRICAL APPARATUS.

No. 595,803. Patented De0.21,1897.

WITNESS INVENTOR M A TTOR/VE) UNITED STATES PATENT OFFICE.

SAMUEL L. BARRIETT, OF NEW YORK, N. Y.

AUTOMATIC SWITCH FOR ELECTRICAL APPARATUS.

SPECIFICATION formingpart of Letters Patent No. 595,803, dated December 21, 1897.

Applicatlonfiletl September 9, 1897. Serial No. 651,154. (No model.)

To all whom it may concern.-

Be it known that I, SAMUEL L.-BARRIETT, a citizen of the United States, residing in New York, in the county of New York and State of New York, have invented certain new and useful Improvements in an Automatic Switch for Electrical Apparatus; and I do declare the following to be afull, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to an improvement in automatic cut-out devices as applied to rheostats, starting-boxes, or other switching apparatus used for electrical purposes; and the object of my invention is to provide a device or arrangement by which the lever, arm, or contact-maker of such switching apparatus is made to automatically return to a given or fixed position (from whatever position it may formerly have occupied) either by reason of an excessive flow of current or when the circuit is by any means broken. In the first instance the device serves as a safeguard against overload currents and short circuits, and in the second instance it provides that the circuit shall remain open until it is desired by the operator to again close it. This latter qualification is important for the reason that should the current momentarily cease it cannot start up again suddenly to the probable detriment of the electrical devices in the circuit.

I shall explain and describe my invention as applied to a rheostat or starting-box to be used in connection with electric motors. In former devices of this class the lever, arm, or contaet-maker is moved from the position of no current or open circuit over a series of contactpoints, decreasing the resistance in the circuit as the arm is moved forward over the successive contact-points until the resistance of the rheostat is all out and the motor is supplied with the full pressure. In this final position the lever, arm, or contact-maker is held (against the pull of a spring toward open circuit) by a suitable catch, depending upon the action of an electromagnet.

A feature of my invention resides in the fact that the lever, arm, or contact-maker will return to its position of open circuit from any position that it may have occupied previous to the excessive flow or cessation of flow of current.

Referring to the drawings, Figure 1 shows a View looking down on top of the startingbox, and Fig. 2 shows a front elevation.

10 and 10 are the main terminals of the instrument and serve to connect it in series with the armature of the motor. The current passes from the left-hand terminal 10 through the coils of the electromagnet 4, (wound with coarse wire,) thence to the contact-plate 9, through the contact-spring 8 and arm 2 to the terminals of the resistance-coils, and so to the right-hand terminal 10. The electromagnet 3 (wound with fine wire) is connected in series with the field-coils of the motor by means of the terminals 1.1 and 11. The arm 2 carries the circular arc of soft iron 1, which acts as a keeper or armature to the magnet 3. One end of this armature is fastened to the arm 2 at 7, while the other end is supported by the piece 6, fastened to the pole of the magnet 3 in such manner that the armature 1 is compelled to slide close to both poles of the magnet, which are shaped to fit it, as

shown.

The action of the instrument is as follows: The magnet 23, being in series with the fieldcoils of the motor, becomes energized when the main-line switch is closed. It therefore attracts the armature 1 and holds it with such force against its poles that as the arm 2 is moved over successive contact-points the torque of the coiled spring 16, tending to return the arm 2 to the position of open armature-circuit, is overcome. The result is at whatever position it is desired to have the arm 2 the magnet 3, acting through the armature 1, will maintain it in that position. If, however, the circuit by any means is broken, the magnet 3 loses its energy and the armature 1 ceases to be attracted. Therefore the coiled spring 16 quickly returns the arm 2 to the position of open circuit. Again, shouldzthe flow of current become too great the electromagnet 4 will become sufiiciently energized to draw up its armature 13 against the force of gravity. \Vhen this happens, the terminals 11 and 11 of the magnet 3 are connected together by means of the contacts 11 and 11 and the armature 13. This shortcircuits the magnet 3, which thereupon becomes demagnetized, allowing the armature 1 to slip past its poles and the arm 2 to open the circuit. The critical excess of current is provided for by adjusting the lock-nuts 14 in an obvious manner.

The foregoing description shows the invention as applied to an ordinary rheostat or starting-box; but the invention is designed to be used with any electrical apparatus where it is desired to maintain any particular part lever arm, or contact-switchin any position and to automatically return the same to a given or fixed position.

Having described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. In a switch for electric apparatus in combination with an arm moving over successive contact-points, and an electromagnet having a curved segmental band-armature, which acts to maintain said arm in contact with any one of said contact-points against the action or force tending to return the arm to off position, substantially as described.

2. In a switch for electric apparatus in combination with an arm moving over successive contact-points and a magnet having a curved segmental band-trniature holding the arm upon any one of said contact-points, means for automatically releasing and returning said arm upon an abnormal flow of current allowing the arm to return from any position to off position, substantially as described.

3. In aswitch for electric apparatus in combination with amovable arm, a segmental bandarmature, suitable means for holding the arm in any desired position, a mechanism to short-circuit the retaining-clectromagnct upon an excessive flow of current, a mechanism adapted to release the arm upon a cessation of a fiow of current, allowing the arm to return to the off position, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

SAMUEL Ii. I-EARIHICT'I.

Witnesses:

CHAS. CONARD. JOHN MARE.

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