US1551379A - Electbomagnetic cibcuit contbolleb - Google Patents

Description

. Aug. 25, 1925. l 1,551,379

' J. EATON ELECTROMAGNETIC CIRCUIT CONTROLLER Original Filed Sept 29. 1921 Figb'.

- Inveht or-: John Eaton,

His Att ornes.

Patented Aug. 25, 1925.

YUNITED S E PATENT OFFICE"? JOHN EATON, or. scnnnEcTAnY, NEW YORK; ASSIGNOIR. T GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

- ELECTROMAGNETIC CIRCUIT CONTROLLER.

Application flled September v29, 1921, Serial No. 504,052. Renewed February 7, 1925.

' To all whom it may concern:

Be it known that I, JOHN EATON, a subject of the King of Great Britain, residing at Schenectady, in the county of Schenectady, State ofNew York, have invented certain new and useful Improvements in Electromagnetic Circuit Controllers, of which the following is a specification.

My invention relates to a circuit controller which combines the feature. of manual control and also the feature of automatic control to protectthe controlled circuit from abnormal conditions such, for example, as an overload or a failure of voltage, although in certain of its aspects the invention is not necessarily limited to a manually controlled switch. 7 V

The present invention is a modified form of the electromagnetic circuit controller, for which I filed an application for patent on September 29, 1921, Serial No. 504,051.

g In carrying the invention into effect, means is provided for closing and opening the controlled circuit at the will of the operator or in response to any predetermined condition. The same means may take the form of open and close or start and stop push buttons, although the invention is not limited to a push button switch, nor are )0 certainfeatures of the invention limited to their use in a manually operated switch. A

switch member is under the control of the said means and also under the control of an electromagnet which may have a single winding energized responsively to the current through the switch. The electromagnetis provided with a magnetic movable member which is under the control of the magnet winding or windings, and the arrangement is such that .the. switch member is magnetically held'thereby in an operative position as long as the conditions in the controlled circuit are abnormal, .or until said manual means is operated to return the switch to its original position. In case an abnormal circuit condition occurs,such, for example, as a failure of voltage, the magnetic holding effect on the said magnetic movable member is released and the switch member is returned from the closed circuit position to the-open circuit position in accordancewith its bias; or in case there is an overload in the controlled circuit, the

magnetic movable member-is tilted to auto- ,"matic'ally open} the I and permit D the air gap 16 may be terme switch member to return to the open pO'si- M tion in accordance with its bias. In the present form of the invention, which has certain advantageous features of construction and arrangement which will be pointed out particularly hereinafter, the magnetic movable member takes the form of a single armature which is biased to a position with respect to the magnetic structure of the electromagnet, to provide two air gaps in series. The arrangement is such that the armature is tilted in one direction so as to substantially close oneof the said air gaps in the flux path of the electromagnet, so that the switch member. is magnetically held by the armature in the closed circuit position as long as the current in the magnet winding is above apredetermined minimum value. In case the current in the anagnet winding rises above a predetermined maximum value, the armature is automatically tilted in the other direction due to the magnetic pull across the second air gap, so as to open the switch and permit the armature and switch member to return to their biased positions. 1

For a better understanding of the invention, reference is had to the accompanying drawings in which I have shown an embodiment of my invention. Referrin to the drawings, Fig. 1 isa side'view o my improved switch in the open position; Fig. 2 is an end view of the same; Fig. 3 is a View showing the switch in the closed position; Fig. 4 is a view showing the relative positions of theparts when the switch is manually opened; and Fig. 5 is a wry simplified diagram' of a motor starting arrangement embodying the invention.

-Referring to the drawin s, the switch member lOis adapted to ma e engagement with the stationary contact 11 to complete an electric circuit through the switch contacts and also to energize the coil 12 of the electromagnet for the switch. Switch member is mechanically connected to the armature 13 and biased to the open position by means of the springl l which also serves as a pivotal support forthe armature. The armature 13 is disposed withrespectto the magnet structure of the switch to provide two air 'gaps and 16. .Theair gap 15 may be termed the closin air gap, and the the opening air Thesw tch is adapted to be manually controlled by means of the close or start push button 17 and by means of the open or stop push button 18. In such an'arrangemerit, when the start push button 17 is depressed, the armature 13 is tilted about the spring 14 as a pivotal support to close the air gap 15, and at the sametime'carry'the" switch member 10 into engagement with the stationary contactll to thereby complete the electric c-ircuit controlled by the switch, and also energize the magnet winding12. Then the current in the magnet winding 12 is above a predetermined minimum value, the 'arinature 13will be maintained in engagement with the upper end of the left hand leg of the U-shaped magnet structure 19ofthe switch. The surface of the upper end of the left hand leg of the magnet structure 1.9 is angularly disposed with respect .to the surface of the right hand leg of the magnetstructure, so that when the switch is closed the armature 18 will be in the position shown in Fig. 3, and the air gap 16 which is open when the switch is closed, will be substantially as shown in Fig. 3. It will be observed that the switch cannot open automatically while the start button is held depressed. This feature is used to advantage when the switch is used as a starting switch for an electric motor which takes a heavy starting current but which takes a substantially lower current for normal running. Such a condition is met in the electric drive for a washing machine, for example, in which the starting torque required is very great and the normal running torque required is very materially less. If the energization of the motor is maintained during this starting interval by maintaining the start button depressed, the motor will come up to its normal operating speed and then the switch will give the automatic protection against overload and voltage failure. hen the current through the magnet winding 12 rises above a predetermined maximum value, the magnetic pull across the air gap 16 will be such that the armature 13 will be caused to tilt in the opposite direction about the spring .14; as a pivot so as to thereby move the switch member 10 a short distance to the left out of engagement with the stationary contact 11 and therebyinterr-upt the circuit throughthe switch. In order for the-switch to be magnetically opened when the current in the winding 12 is above the predetermined maximum value, it is not necessary that the air gap 15 be entirely opened as shown in Fig. 4:, but it is merely necessary that the left hand end of the air gap 15 be opened :su'fiicieiitly to permit the switch member'lOto, break engagement with the stationary contact 11. Fig. 4 shows therelar 5 tive-positions of the parts when the switch is manually" opened, and it willbe understood that when the switch is magnetically opened due to the current in the magnet winding rising above a predetermined value, the armature'is merely tilted. toha position approaching theposition shown in Fig. l, but the air gap 16 is not necessarily closed. As thus constructed and arranged, the operation of my invention may be readily understood from a description of F ig, 5. In order to close the switch, the push button 17 is depressed, thereby connecting the motor 20 across the source of supply 21, at the same time energizing the magnet winding 12 so that the armature'13 is magnetically held in the position shown in Fig. 3. As long as the current'in the magnet winding is above a predetermined minimum value, the switch will be magnetically held'closed, but in case the power of the supply circuit should fail,the armature will be permitted to return to the position shown in Fig. 1, thereby interrupting the circuit through'the electric motor and the magnet winding 12. The switch will remain in the open position until'the operator again closes the same,

or until the switch is closed in any suitable manner in response to any predetermined condition,

Ifwhile the switch is magnetically'held closed, the current taken by the motor should rise above a predetermined maximum value, the magnet winding 12' will be energized to set up a flux which will produce a pull on the right hand end of the armature 13 tending to close the air gap 16, and the armature will thereby be tilted about the spring ll a short distance so as to interrupt the circuit through the switch and permit the parts'to resume their relative positions shown in Fig. 1. The motor is thus automatically disconnected from the source of supply.

hen .used as a push button or manually operated switch, the invention has the advantages that the switch not .only serves the purposes of theordinary start andstop push button arrangement, but it also combines the features of providing voltage failure and overload protection. It will also be observed that a single winding is necessary for magnetically holding the switch closed as long as the current in the winding is above a .predetermined minimum value, and for magnetically opening the switch when the cur rent in the magnet winding is above the predetermined maximum value.

The broad general features of an electromagnetically controlled device which is ,provided with a movable controlled member biased to one position, magnetically held in a second position against its bias when the ene'rgizatfion of the controllin electr om'agnet s above a p ed te m ned m mllm e u when the energization of the electromagnet is in excess of a predetermined maximum value, is broadly claimed in my said application, Serial No. 504,051, filed September 29, 1921. Furthermore, in my said former a plication I have broadly claimed a manua ly operable automatic overload and undervoltage protective switch having the broad general features above set forth and arranged so as to be manually opened or closed at the will of the operator. The invention of this application is directed to a particular arrangement having the above broad gen-e represent the best embodiment thereof, but

I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States, is

1. An electric switch comprising a switch member biased to the open position, a controlling electromagnet therefor comprising a magnet structure and a winding energized responsively to the current through the switch, an armature for the electromagnet connected to the switch member and biased away from the said magnet structure to provide two air gaps in series, means for tilting the said armature in one direction to close the switch and to substantially close one of said air gaps, whereby the said switch member is magnetically held in the closed position when the current in the said winding is above a predetermined minimum value and the said armature is tilted in the other direction by the magnetic pull across the second air gap to open the switch when the current in the said winding is above a predetermined maximum value.

2. An electric switch comprising a switch member, a controlling electromagnet therefor comprising a magnet structure and a winding energized responsively to the current through the switch, an armature for the electromagnet connected to the said switch member, means for biasing the said armature away from the said magnet structure to bias the switch member to the open position and to provide two air gaps in series between the said armature and magnet structure, means for tilting the said armature in one direction about the said biasing means as a pivotal support to close the switch and to substantiall close one of said air gaps, whereby the said switch member is magnetically held in the closed position when the current in the said winding is above a predetermined minimum value and the said armature is tilted in the other direction by the magnetic pull across the second air gap to open the switch when the current in the said winding is above a predetermined maximum value.

3. An electric switch comprising a switch member, a controlling electromagnet therefor comprising a magnet structure and a winding energized responsively to the current through the switch, a single piece armature for the electromagnet connected to the switch member, a spring for holding the said armature away from the said magnet structure to bias the switch member to the open position and to provide an air gap between the armature and magnet structure on each side of said spring, manually operated means for tilting the said armature in one direction about the said s ring as a pivotal support to close the switc and to substantially close one of the said air gaps, whereby the said switch member is magnetically held in the closed position when the current in the said winding is above a predetermined minimum value and the said armature is tilted in the other direction about the said spring to open the switch by the ma etic pull across the air gap on the other side of the said spring when the current in the said winding is above a predetermined maximum value.

4. The combination in a push button switch of a switch member,a push button for closing the switch and a push button for opening the same, a controlling electromagnet having a U-shaped magnet structure and a winding therefor in the circuit controlled by the switch, an armature for the said electromagnet connected to the said switch member and arranged to be operated by the said push buttons, the said armature disposed with res ect to the said magnet structure to bridge t e poles thereof and biased away therefrom to provide two air gaps in series relation, whereby the said armature is tilted to close the switch and to close one of said air gaps by the operation of the closing push button, and the switch is magnetically held in the closed position while the current in the said winding is either above a predetermined minimum value or below a predetermined maximum value.

In witness whereof, I have hereunto set my hand this 28th day of September, 1921. JOHN EATON.

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