US1572917A - Short-circuiting device - Google Patents

Description

Feb. 16 1926.

INVENTOR Georg/e /7f. Ga/ce/w? G. H. GARCELON SHORT CIRCUITING DEVICE Filed June 30, 1923 WITNESSES:

ATTORNEY sitions.

Patented Feb. 16, 1926.

UNITED STATES.

PATENT i OFFICE.

GEORGE H. GARCELON, QF SWISSVALE, PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VANIA.

SHORT-CIRC'UITING DEVICE.

Application filed June 30, 1923. Serial No. 648,714.

To all whom it may concern:

Be it known that I, Gnome H. GARcnLoN, a citizen of the United States, and a resident of Swissvale, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Short-Circuiting Devices, of which the following is a specification.

My invention relates to short-circuiting devices and it has particular relation to short-circuiting devices for alternating-cur rent motors that operate during the starting period as repulsion motors and at full speed as close-circuited induction motors.

In the co-pending application of W. H. Himes, Serial No. 660,120, filed August 30, 1923, and assigned to the lVestinghouse Electric and Manufacturing Company, there is described a short-circuiting device employing a plurality of centrifugally actuated balls which are guided by radial slots in a fixed retainer, whereby they move along fixed paths upon the face of the commutator to their outward close-cireuiting po- This device has a special rollingspring arrangement which renders it ren'iarkably free of friction, thus entirely eliminating the'sluggish action encountered in other devices embodied in motors of the same type.

It has been found that, in the operation of the short-circuiting devices of the abovedescribed type, there is a slight tendency for the balls to wear a grooved track in the end face of the commutator, because of their rapid movement along the slots of the fixedrctainer each time the motor is started.

An object of my invention is to provid an improved short-circuiting device that is arranged to secure uniform wear of the running surface thereby eliminating the tracking action of the ball members.

A further object of my invention is to provide a novel detail of the guiding slots of the retaining member for very greatly facilitating the assembly of my device on a very large-scale production basis.

With the foregoing and other objects in view, my invention consists in the noveldetails and combinations which will be best understood by reference to the accompanying drawing, wherein Fig. 1 is a vertical sectional view of the tion 4- of insulating material and conducting bars 5 mounted on the circumference thereof.

The short-circuiting device 1 comprises a substantially cylindrical hub member 6, a

ball retainer 7 rotatably mounted upon the hub member ad'acent to the face of the commutator, and a guide plate 8 secured to the hub member in spaced relation to the ball retainer. The hub member 6 is retained on the shaft 2 by means of a locking ring 9 that'is forced into a groove 10. The ball retainer 7 is of substantially cireular shape and is provided with a plurality of radiallydisposed slots 12 which are Wider at their outer ends than at their inner ends, as will be explained hereinafter. The retainer is re tained on the hub member by means of atlange 18 extending from the latter 0n the comn'iutator side of the retainer.

The guide plate 8 is secured to the hub member (3 by means of a locking ring 1 1 which is sprung into a groove 15 in the hubmember. The guide plate 8 has an inner or intermediate portion 16 which is disposed parallel to the commutator face and which merges, at a predetermined distance from the center, into a conical portion 17 extending away from the commutator.

Balls 18 of conducting material such, for

example, as bronze, are mounted loosely within the slots of the ball retainer 7 for movement in radial directions along the slots and also for rotative movement with the. retainer relatively to the remaining parts. A substantially annular tension member such as a garter spring 19 surrounds the balls and, through a wedging action between the outer portion of the balls 18 and the guide plate 8, forces the balls into a central position and into engagement with the end face of the commutator. By reason of its circular cross-section, the garter spring 19 has a special rolling action which renders it particularly effective in reducing friction, as noted hereinabove in connection with the copending Himes application. Thus, the convolutions contacting with the balls 18 at any instant operate like idler rollers between the balls and the guide plate 8, and the rcmaining convolutions of the garter spring operate like resilient connections between such idler rollers.

In operation, each time the motor is started, the inertia of the balls and of the retainer will cause them to slip back a little with respect to the remaining parts of the apparatus, thus causing the balls to maintain a polished surface over the entire end of the commutator, and preventing uneven wearing or burning of the parts. I

With increasing angular speed, the centrifugal force acting upon the balls will cause them to roll outwardly against the restraining force of the garter spring 19. This movement may be relatively slow until the spring 19 reaches the inclined portion 17 of the guide plate 8, the retaining force of the garter spring 19 being thereupon substantially diminished by reason of the angle of its application. The balls will thus move rapidly to their short-circuiting positions in engagement with the commutator bars 5.

In the outer positions of. the balls 18, as indicated by dotted lines 18, there is a well defined wedging action of the balls between the commutator bars 5 and the outer ends of the slots 12 of the retainer 7, such action being obtained by causing the retainer to be bent outwardly away from the commutator,

whereby the armature current is carried by the conducting retainer 7, thus effectively shunting the garter spring and protecting it from the destructive efl'ect that might result, were it permitted to carry current. l/Vhen the motor stops, the balls close in with a positive movement, the smooth side walls of the slots 12 ofiering no hindrance to the balls as they enter the narrower inner portions of the slots.

The retainer plate 7 and the guide or abutment plate 8 are provided, at their peripheries, with flanged portionsQO and 21, respectively, which approach each other in such manner as to limit the outward movement of the spring 10, thereby protecting it from damages that might result from overspeeding ot' the motor.

The device may be assembled as a separate unit, the inner ends of the slots 12 being sutliciently narrow to prevent the passage of the balls therethrough. When the hub member is detached from the commutator, the balls may be inserted in, or removed from, the cage through the wider outer portions 22 of the slots 12 as shown in Fig. 2. The sored of assembling the parts is thereby greatly increased, particularly whcn (p1aIititv-production methods are 'cimshhrcd.

A motor equipped with a starting device embodying my invention has operated for approximately 250,000 starts, after which the device was taken down and minutely examined. No trouble whatever had developed, neither the commutator segments, the end face of the commutator nor the balls were pitted, and the amount of wear of the halls wa not sufficient to be detected with a micrometer caliper. The only change noticed was a slight discoloring of the balls and a polished, discolored band upon the face of the commutator corresponding to the ever changing tracks of the balls in their outward and inward movements.

The extreme simplicity and ease of manufacture as well as the small space necessary for installation ot'the device, are apparent from the drawing. While I have shown a particular embodiment of my invention, it will be obvious to those skilled in the art that it is susceptible of other modifications and art'ore, that only such limitations shall be placed upon my invention as are required by the prior art or as are set forth in the appended claims.

I claim as my invention:

1. The combination with a rotor of a dynamo electric machine having a plurality of circumferentially disposed contact members of a close-circuiting device secured to said rotor, said close-cireuiting device comprising a plurality of close-circuiting members adapted to move under centrifugal action to an outwardclose-circuiting position in engagement with a plurality of said contact members, a yielding restraining member opposing said movement, and retaining means whereby said close-circuiting members may assume difl'erent circumferential positions relative to said rotor.

2. The combination with a rotatable commutator member of an electric machine, of a plurality of spherical close-circuiting members arranged to move outwardly under centrifugal action, a yielding tension member encircling said spherical members for restraining said movement, a guide member associated with said spherical close-circuiting members and rotatably mounted with respect to said commutator member, and a guide mcmer associated with said tension member and rigidly coupled to said commutator member, whereby upon the acceleration of said commutator member, said spherical members move outwardly with a combined radial and circumferential movement.

3. The combination with a dynamo clcc tric machine having a commutator cylinder, ol a short-circniting device, comprising a plurality of spherical short-circuiling incinbcrs. in engagement with the end l'acc. of said commutator cylinder, relatively retatable means associated with said commutator cylinder for retaining said members in spaced relation and for guiding the same in outward movement, a yieldable tension member encircling said spherical members, and an abutment plate for causing said tension member to exert, upon said spherical members, a pressure having one component toward the commutator cylinder and another component toward the axis of rotation.

4.1K centrifugal contact-making device comprising a plurality of annularly disposed rolling members which are movable outwardly under the action of centrifugal force, a cylindrical commutator member having a plurality of peripheral segment members and having an end surface against which said rolling members roll, means for providing another abutment surface spaced from said rolling members, and anti-friction means yieldably engaging said rolling members in rolling engagement therewith and with said other abutment surface for yieldably restraining said rolling members against outward movement, said rolling members having such freedom of rotative movement with respect to said commutator cylinder that they occupy different positions circumferentially of said cylinder upon successive startings thereof 5. A centrifugal contact-making device comprising a plurality of annularly disposed spherical members which are movable outwardly under the action of centrifugal force, a commutator cylinder having a plurality of peripherally located segments and having an end surface against which said spherical members roll, a coil spring surrounding said spherical members, and means for providing an abutment surface for said spring, said spherical members having such freedom of rotative movement with respect to said commutator cylinder that they occupy different positions circumferentially of said cylinder upon successive star-tings thereof."'

6. A self-contained speed-responsive attachment comprising a hub, a guide plate rotatably mounted thereon and having subrotatably mounted thereon and having sub-,

stantially radially disposed slots, an abutment plate secured to said hub in spaced relation to said guide plate, a plurality of annularly disposed balls disposed in the space beeween said plates and projecting partially through said slots, respectively, and a coil spring surrounding said balls and engaging said abutment plate.

8. A self-contained speed-responsive attachment comprising a hub, a guide plate carried thereby and having a plurality of substantially radially disposed slots, an abutment plate secured to said hub in spaced relation to said guide plate, a phirality of annularly disposed roller members disposed in the space between said plates and having their rolling surfaces projecting through said slots, respectively, means for preventing the passage of the entire roller members through said slots in the inner portions thereof, the outer ends of said slots being sutficiently wide to permit spaced relation to said guide plate, a plurality of annularly disposed balls disposed in the space between said plates and projecting partially through said slots, respectively, in the inner portions thereof, the outer ends of said slots being suiticicntlv wide to permit the passage of said balls therethrough, and a coil spring surrounding said balls and engaging said abutment plate.

10. The combination with the commuta tor cylinder of an electric motor, of a speedresponsive, circuit-closing device comprising a guide plate mounted for relative rotational movement adace'nt the end of said commutator cylinder, said guide plate having substantially radially disposed slots, a plurality of annularly disposed weight members movable in said slots under the action of centrifugal force and means for yieldably restrainingsaid weight members against centrifugal movement, said slots having closed ends for limiting said centrifugal movement and for so engaging said weight members as to cause the centrifugal action to wedge the Weight members between said commutator cylinder'and said slot-ends.

11. The combination with the commutator cylinder of an electric motor, of a speed carried thereby and having a plurality of substantially radially. disposed slots, an abutment plate secured to said hub in spaced relation to said guide plate, a plurality of annularly disposed roller members disposed in the space between said plates and having their rolling surfaces projecting through "said slot-s, respectively, means for preventing the passage of the entire roller members through said slots m the lnner portions thereof, the outer end of said slots being sufiiciently wide to permit the passage of said roller members therethrough, and a coil spring surrounding said roller members and engaging saidabutment plate, whereby said roller members may move outwardly under the operation of centrifugal force against the reaction of said spring, the outward movements of said roller members being limited by the outer ends of said slots, the outer portion of said guide plate being inclined toward said abutment plate whereby said roller members, in their extreme outer positions, are forced away from said abutinent plate by the centrifugal force pressing the roller members against said slot-ends.

13. A self-contained speed-responsive attachment comprising a hub, a guide plate carried thereby and having a plurality of substantially radially disposed slots, an

abutment plate secured to said hub in spaced relation to said guide plate, a plurality of annularly disposed balls disposed in the space between said plates and projecting partially through said slots respectivelv, in the inner portions thereof, the outer ends ol' said slots being sutliciently wide to permit the passage of said balls therethrongh and a coil spring surrounding said balls and engaging said abutment plate, whereby said balls may move outwardly under the operation of tentrifugal force against the re action of'said spring, the outward movements of said balls being limited by the outer ends of said slots, the outer portion of said guide plate being inclined toward said abutment plate whereby said balls, in their extreme outer positions, are "forced away from said abutment plate by the centrifugal force pressing the balls against said slotends.

14. In combination with the rotatable connnutator member of an electric machine, a plurality of spherical close-circuiting contact members arranged to have circumferential movement relative to said commutator member and adapted to move outwardly under centrifugal action, an annular tension member of substantially circular cr0ss-section surrounding said spherical contact members and tending to retain said membcrsiin central positions, and guide means for causing said spherical members. upon retelling a predetern'iined speed. to partially displace said tension member and thereby diminish its restraining action.

In testimony whereof, l have hereunto subscribed my name this 27th day of June onones n. eancnrou.

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