US1024807A - Automatic starting device for single-phase induction-motors. - Google Patents

Description

P. J. RAY,

AUTOMATIC STARTING DEVICE FOR SINGLE PHASE INDUCTION MOTORS.

APPLICATION FILED JAN. 25, 1912.

Patented Apr. 30, 1912 Inventor I Attorneys UNITED STATES- PATENT OFFICE.

PAUL J. BAY, OF LAKEWOOD, OHIO.

Specification of Letters Patent.

Patented Apr. 30, 1912.-

Application filed January 25, 1912. Serial No. 673,340.

1b all whom it may concern:

, Be it known that I, PAUL J. RAY, a citizen of the United States, residing at Lakewood, in. the .county of Cuyahoga and State of Ohio, have invented anew and useful Auto matic Starting Device for Single-Phase Induction-Motors, of which the following is a specification.

The present invention relates to improvements in automatic starting devices for single phase induction motors, the primary object of" the invention being the provision of a starting with therotor of themotor and provided with a cut out connected in series withthe starting coils, and having a circuit closer disposed to be normally closed when stationary and to automatically cut out due to centrifugal force when the rotor has attained its speed. I

lVith the foregoing and other objects in view which will appear as the description proceeds, the invention resides in thecombination and arrangement of'parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of invention herein disclosed can be made with in the scopeof what is claimed without departing from the spirit of the invention.

In the drawings-Figure 1 is a vertical central sectional view through the cut-out with the coils of the induction motor shown in diagram. Fig. 2 is a section taken on line 2-.-2 oi? Fig. Fig. 3 is a front elevation of the cutout. F ig, 4 is a partial sectional view through a vertical type of cutout showing the modified construction necessary, but employing the same principle as used in the device shown in Figs. 1, 2 and 3. ig. is an enlarged detail viewshowing the normal position of the liquid circuit closer.

Referring to the drawings, the numeral 1 designates the rotor shaft which has mounted thereupon and rotatable therewith.

the cut-out C, which consists of the inner circular disk 2 of insulating material, preferably of a close grain wood. or fiber, while surrounding the same in concentric relation thereto is an annular ring 3 of the same material. The face of the ring 3 adjacent to the periphery of the disk 2 is provided with the annular channel 4.- which provides a chamber within the ring 3 and about the device carried and rotatable disk 2, the purpose of which will presently appear.

Connected to the-flat face of the annular ring 3 near the outer circumference thereof 18 a metal contact plate 5 while disposed "concentrically thereto and in spacedrelation t'erewith is another metal contact-plate 6, both of said plates being connected to the saldannular ring 3 in such relationas to provide the space or gap- 7 between the respective plates 5 and carried by the circumferential-face ofthe disk 2 are the two metal contact rings 8 and 9 which provide the intermediate circumferential space 10, which. is filled with shellac which is permittedto become dry and hard and forms a closure for the annular channel or chamber 4, so that the fluid circuit closer 11, mally assumes the position Within the lowermost portion of said channel or chamber 4 as clearly shown in Figs. land 2. When in such positions, the said fluid circuit closer contacts a portion of the respective plates 8 and 9 and thereby closes the gap therebetween and forms an electrical connection between said plates, the lower lapping edge of the contact plate 6 carried by the annular ring 3 is projected as at 13 so asto contact the outer face of the ring 9, while a conductor 12 leads from the contact plate'or ring 8 to the contact plate 5 through the preferablyof mercury, nor- 6. Mounted upon andv body of the annular ring 8, thus forming an' electrical connection between the ring 8 and tact normally between plates 8 and 9. i

Carried by the block 14 of insulation are the two metal brush holders 15 and 16 respectively, which have mounted therein the two brushes 17 and 18, respectively, each of said brushes being held toward and in engagement with the respective contact plates 5 and 6 by means of the springs 19 and cap 20.

Connected to and leading away from the respective caps 20 Y are the conductors 21 and 22, the conductor 21 being connected to the starting coil 23 of the induction motor M, while the conductor 24 leads thereaway from the motor terminal P which has led thereinto the line wire L. The conductor 22 is connected to the terminal P of themotor.

Connected to the respective motor terminals l? and P are the conductors 26 and 26 which are connected to the main coils 2 7 of plate 5, while the mercury 11 closes the co the induction motor, thus providing means whereby the starting coils 23 are connected to the main line terminals of the induction motor and also are connected in shunt with respect to the main coils of the induction motor.

In theform of cut-out C as illustrated in- Fig. 4, the members 2' and 3, respectively, correspond .to the members 2 and 3 as heretofore described, and are provided with the fiuid circuit closer retaining annular channel a, while the member 3 upon the upper flat face thereof carries the two brush contact annular plates 5 and 6', respectively, which are spaced as at 7 to be engaged by the respective contact brushes 1''? and 18, the detail structure of which and the connection of which to the respective terminals of the induction motor are identical with that heretofore described. In this form, however, the two rings 8 and 9', which correspond to the rings 8 and 9 heretofore described, are disposed in opposite relation to form the opposed walls of the horizontally disposed annular channel 4' to provide the pocket for the fluid circuit closer 11, which due to centrifugal force when the cut-out C is rotated will 'be thrown outwardly and up the ii-lined' face of the ring 8" and thus out of contact with the ring 9, thus opening the circuit when the motor has obtained its proper speed. The contact ring 8 is connected to the contact plate 5' through the conductor 12, while a conductor 28 connects the plate 6 to the ring 9. By this construction it will be seen that the same principle that is employed in the horizontal form of cut-out shown in Figs. 1, 2 and 3, can be employed to advantage in a vertical form of cut-out as shown in Fig. l.

\Vhen operating the-present device, the. current is thrown into the single phase induct-ion motor M, the same requiring a rotating field to start the rotor and bring the same to full speed, and the cut-out being stationary, the current passes through the stationary coils by way of the motor terminals P through the conductor 22 to the stationary brush holder 16 and its brush 18, to the flat copper current conducting plate 6, thence to the cylindrical ring 9, which is short circuited with the cylindrical ring 8 by the mercury 11 in the lower portion of the slot as viewed in Figs. 1 and 2. The current continuing to flow from the cylindrical ring 8 through the conducting wire 12 to the flat contact plate 5, through the brush 17 and holder 15, and conductor 21 to the starting coils 23 and from the starting coils to the motor terminals P. As a rotating field is caused to beset up by the current in the starting coils, which constitute part of the primary winding of the induction motor, the rotor and cut-out being fixed to the rotor shaft, rotates, the mercury or fluid circuit closer 11 in the annular channel 4 or t, is actuated, due to the centrifugal force, and is thrown outwardly into the insulated portion of said annular channel as, the rotor speed is accelerated. This action causes the fluid circuit closer and breaker, or the mercury, to sever the con-' nection between the rings 8 and 9, or 8 and 9', the starting coils being thus cut out of the circuit when the rotor has acquired full speed, the said rotor still continuing to run under the influence of the main coils 27.

\Vhen the current is cut off, the motor M- stops and the action of gravity" upon the mercury 11 causes the same to assume its original position as shown-in Figs. 1 and 2 at the lowest portion of the channel t, thus connecting the starting coils 23 to the motor terminals P and P the same as before the motor was started. It will thus be seen that the automatic control of the starting coils depends upon the action of the centrifugal force and gravity of the fluid circuit closer carried in the cut-out, and further that the same principle may be employed as well in a vertical type of cut-ont as in a horizontal type as before set forth.

\Vhat is claimed is:

1. The combination in a self-starting single phase induction motor, of main and-starting coils, and a centrifugal cut-out device therefor connected in series with the starting coils of said motor and rotatable therewith, said cut-out comprising two concentric bodies of insulation, a contact plate carried by each body, said bodies being provided withan interposed annular channel, and a fluid circuit closer occupying a portion and within the channel to close the circuit through the plates when the motor is stationary and to open the circuit due to centrifugal force when the motor acquires spee 2. The combination in a self starting single phase induction .motor, of main and starting coils, and a centrifugal cut-out device therefor connected in series with the starting coils of said motor, and rotatable therewith, said cut out comprising two concentric bodies of insulation, a contact plate carried by each body, said bodies being provided with an interposed annular channel, and mercury occupying a. portion of and within said channel to closethe circuit through the plates when .the motof is stationary and to open the circuit due to centrifugal force when the motor acquires speed.

3. The combination in a self starting single phase induction motor, ofmain and starting coils, and a centrifugalcut-out device therefor connected in series with the startin coils of the motor and rotatable therewith, said cut-out comprising two con centric bodies of insulation, a contact plate carried by each body, said bodies, being provided with an interposed annular channel, and a fluid circuit closer occupying a portion thereof and within the channel to close the circuit through the plates when the motor is stationary and to open the circuit due to centrifugal force when the motor acquires speed.

4, The combination in a self starting single Phase induction motor, of main and starting coils, and a centrifugal cut-out device therefor connected in series with the starting coils of the motor and rotatable therewith, said cut-out comprisingtwo concentric bodies of insulation, a contact plate carried by each body, said bodies being provided with an interposed annular channel, and mercury occupying a portion of and within said channel to close the circuit through the plates when the motor is stationary and to open the circuit due to centrifugal force when the motor acquires speed.

5. The combination in a self starting single phase induction motor, main and starting coils; and a centrifugal cut-out device for the motor carried by and rotatable with the rotor thereof and connected in series with the said starting coils and provided with an inclosed annular channel, said outout having two circular contact surfaces insulated from'each other, and a fluid circuit closer occupying a portion of and within the channel, whereby when the motor is stationary, the fluid circuit closer will'contact both circular plates and when the motor is rotating to acquire speed will, due to cent-rif ugal force, be moved out of contact with said circular plates.

6. The combination in aself starting single phase induction motor, main and start-- ing coils, and a centrifugal cut-out device for the motor carried by and rotatable with the rotor thereof and connected in series with said starting coils and provided with an inclosed annular channel, said cut-out having two circular contact surfaces insulated from each other, and mercury occupying a portion of and within thcchannel,

whereby when the motor is stationary the mercury will conti/ct both circular plates and when the motor is rotating to acquire speed will, iduei. to centrifugal force, be moved out of contact with said circular plates.

In testimony that I claim the foregoing as my own, I have hereto aiiiXed my signature in the presence of witnesses.

' PAUL J. RAY.

Witnesses:

G. ONEILL, F. B. ARNOLD,

E. D. RAY.

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