US1357403A - Centrifugal governor - Google Patents

Description

A. KIMBLE.

CENTRIFUGAL GOVERNOR.

APPLICATION FILED 0CT.2I, 191B.

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WITNESSES.-

"UNITED STATES PATENT OFFICE.

nus'rm xiijunm, or'wausau, wrsco rsm, Ass'reno'n TO, MARATHON ELECTRIC mm co rrANY, orwavsau, wrsconsm, A ooarormrron or WISCONSIN.

cEN'rmrUeAr, GOVERNOR.

Patented Nov. 2, 1920.

Application filed October 21, 1918. Serial No. 259,086.

"To all'whom it may concern: 1 Be it known that I, AUSTIN Kuvrnnn, a

ernors of the centrifugal type, adapted for instance to control a switch, clutch, valve or other mechanism, and more particularly it relates to electric motors of the split-phase induction type having automatic means for cutting out the auxiliary field winding, depending on the speed of the rotor.

The main objects'o-f this invention are to provide automatic switching means of improved form and operation adapted to control' the auxiliary field circuit of a splitphase induction motor; to provide for such a. motor governing means responsive to speed variations and adapted to operate in one direction to openthe circuit at a certain speed as the speed increases, as in starting,

and to closethe circuit at a certain lower speed as the velocity decreases; to provide in sucha dev1ce a switch in combination with a centrifugal governor therefor including' a resilient part adapted for actuation outward by centrifugal force when the rotor comes up to a certain speed and adapted to retain its outward or expanded position un-' til thespeed of the rotor has diminished to a point substantially below that at which the governor is initially actuated; and to provide a centrifugally operable expansible annulus governor adapted to operate one way .at one speed and-to reverse at a different speed.

An iilustrativeembodiment of this inven-v tion is shown in the accompanying drawings, in Tvvhich Figure 1 is a side elevation of the governor and that end of the rotor on whichit is mounted, and shows also that switch contact which is carried by the overnor.

Fig. 2 is a section on t e line 33. of

Fig. 1.

F ig..3 is a section on the line 3-3 of Fig. 2, and'also includes part of the Sta-- tionary frame.

Fig. 4 is also a section on the line 33 of .the drawings, such parts only. of a splitphase induction motor are included as are considered necessary for ex laining the in vention. Referring to said rawings, the rotor 1 is of the squirrel-cae type and comprises a laminated core 2 fixed on the shaft 3, as usual in induction motors.

The stator or field member is provided with a main winding 4 and an auxiliary winding or teaser 5 disposed at an angle thereto and designed to act as a starting coil,-

as understood in the art and as customary in split-phase motors, a switch 6 being provided for cutting out the winding 5 under normal running conditions, subject to automatic control by a governor 7- according to speed, as hereinafter described. I

The governor 7 is mounted on said shaft 3 adjacent, to said core 2, being preferably spaced somewhat from the copper end-ring 8 and adjacent tips of the interconnected hollow bars 9 constituting the squirrel cage member, so as to avoid interfering mate-rially with the ventilatin draft through the conductor fiues .10, whic flues may be substantially like those described in my copending application, Serial No. 235,247, filed he general shapelof the main body of said governor 7 is discoidal, and the outer edge is to advantage substantially flush with the cylindrical face of the core 2.- Said governor comprises a centrifugally responsive member 11 in the form of an endless helical spring .of annulus shape, in combination with apair of corioidal ides or retainers 12 and 13 disposed with their convex faces toward each'othe'r, one'being.

fixed relative to the shaft 3 and the other ingly embraced slidablybetween them. Said means 14 is '"in'the form of a helical spring the loops of which are substantially con-.

centric with said shaft. Said spring 14 is I arranged in compression between the outer side of the slidable member 13 and a stopring on shoulder 15 which is substantially rigid with said shaft. The helical spring member 11 is free of positive connection to the rest of the governor and may be said to be 'in floating relation thereto.

The switch 6 includes a substantially stationary contact 16 carried by the frame or housing 17 and a rotary contact member 18 of ring-shape carried by the axially slidable member 13 of the governor, in such relation that operation of the governor in one direction, as in speeding up, serves to open the switch, and "ice versa. Said switch also includes another stationary contact 19 similar to 16 also arranged to coact with the ring 18 in like manner, said contacts being disposed preferably on opposite sides of the shaft 3, and each being supported somewhat yieldingly on resilient conductor arms 20 which in turn are securedto aninsulating block 21 fixed on said frame 17 at one side of shaft 3. Said switch is connected in series with the starting circuit by means of the leads 22 and 23 attached to the arms 20' respectively. Said arms 20 are preferably made in the form of leaf springs, and the contact blocks 16 and 19, preferably made of carbon, which bear on the switch-ring 18 may to advantage be fastened in place interchangeably on said arms, as by screws 24, so as to facilitate renewal.

The inner member or plate 12 of said governor is adapted for stamping from sheet metal and comprises a flat middle part perforated centrally to receive the shaft 3. The outer part of said plate flares conoidally at 25 toward the core'2 and terminates peripherallyv in a series of spaced teeth' 26 turned abruptly in the opposite direction and disposed nearly parallel with the shaft,

The inner part of said plate fits against an outwardly facing shoulder 27 on said shaft and is thereby held in definite spaced relation to the core 2. The complementary governor guide member 13 includes a plate 28 substantially similar to plate 12 but facing oppositely so that their respective'fiares at 25 and 29 are mutally divergent;- -The teeth 30 on plate 28.are adapted to interfit with and lap past the teeth 26 of plate 12 when the governor is at rest and contracted When the governor is expanded, the tips of all of saidteeth come substantially into circular alinement and the teeth as. a whole constitute a kind of barred cage or peripheral retainer which serves to limit the a radial expansion of the resilient annulus 11 when the rotor cames up to speed. The

inner part of plate 28 adjacent to its per- .ning position.

- nulus.

Q memos sleeve 31. The opposite end of said sleeve is secured to a radially disposed disk 32 also" serves to support the switch-ring 18 in opera'tive relation to the stationary contacts 16 and 19 whenever it is moved into its runsleeve 31 are substantially parts of the axially movable member 13 of the governor 7 and hence responsive to the centrifugally induced movements of the spring 11.

lln. starting the motor by closing the current supply switch 33, the operation of the device is as follows: Initially the governing annulus 11 is contracted 'so that the plates 12 and 18 are forced apart and the switch is closed and both field windings are effective, but as the rotor speeds up, centrifugal force operates to gradually expand said an- As soon as said annulus recedes outward sufliciently over the conoidal faces of Said ring 18, disk 32, and.

walls 25 and 29, the slidable member 13 is friction, and pulls itself wedgingly inward between said members 12- and 13 and so,

forein the latter outward, serves to close the sw tch 6 atcontacts 16 and 19. Then unless the fnain switch 33 has been opened the motor will again operate as a split phase machine and so carry the extra load, and speed up again to normal, as soon as the load will permit. 7 w

in stopping the motor upon opening the power supply switch 33, the speed will immediately fall gradually, thus permitting the annulus 11 to contract and so close the auxiliary field control switch 6 ready for starting again, though such reverse operation of the overnor and switch occurs at a substantial y lower speed than required for there are frequent overloads, because in such machines the auxiliary winding is ordinarily very inefiicient respecting its consumption of power and should be thrown in only on suc overloads as are suflicient to slow down *the speed very materially, whereas in start- "effectually controlled.

ing the motor said winding should be permitted to remain in circuit until the rotor has acquired approximately full speed. The speed interval between the cut-out speed in speeding up and the lower cut-in speed in slowing down depends on several factors in design, as for instance the relative length and stiffness of the annulus 11, the resiliency of spring 14, and the conical pitch of the members 12 and 13.

Although but one specific embodiment of this invention has been herein shown and described, it will be understood that numerous details of the construction shown may be altered or omitted without'departin from the spirit of this invention as defined y the following claims.

I claim: p

1. In a centrifugal governor, a yielding annulus resiliently expansible peripherally at a certain speed by centrifugal force acting on its own mass, and. guide means therefor mechanically responsive to the movement of said annulus, said means including inner and outer parts bearing yieldingly against said annulus and having fixed radial distances from the common axis, one of said parts including a switch controlling member, and said annulus being movable between said parts, whereby the switch actuating part is 2. A centrifugal "governor including a part expansible by centrifugal force at a certain speed and operatively contraetible solely at a substantially lower speed, said part being in the form of a resilient annulus dis-, posed coaxially with the governor, and a conoidal body also disposed coaxially thelgovernor in-coaetive relation to sand part for relative axial movement.

3. A centr fugal governor eomprlsing a shaft, a pair of conoidal retainer guides V mounted eoaxially on said shaft with their convex sides facing toward each other and one of them: being slidable axially, means urging said guides together, and a centrifugally expansible annulus disposed between said guides in operative relation to said s1 es.

L. A centrifugal governor comprising a shaft,v a pair of conoidal retainer guides mounted eoaxially on said shaft with their convex sides facing toward each other and one of them being slidable axially, means urging said guides together, and acentrifugally expansible annulus disposed between said guides in operative relation to said sides, said guides having their outer edges turned reversely and toward each other and said edges being formed with alternate teeth and notches whereby said edges may interfit October, 1918.

AUSTIN KIMBLE.

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