US936360A - Induction-motor. - Google Patents

Description

arranged to cut out the resistance automaticsenseo.

nutren sufrir l' irn- T FF@ CONWAY ROBNSQN, CF SCHENECTAID', Alt'ltr' ZREL SSGNOR TG GENERAL ELECTEIG COMANY, A CORPORTGN GF NEW YGBK.

IENDUCTION-MTR.

To all when?, it may concern.'

Specification of 'Letters Patent.

Application filed February i4, 1906.

[connections ot the rotor conductors that Patented. 9ct. t2, 199th... serial No. 301,025.

Be .it known that l, CONWAY RoerNsoN, e this distribution ot' the mercury provides e sistenee should be short-circuited when the motor is upto speed. This short-circuiting` of the resistance may be done by hand or automatically, and for this purpose centrifugally actuated switches have been sometimes employed heretofore, the rotor conductors-being short-circuited through' a resistsnce at starting and the switch being ally when the motor is up to speed` In orderthat these switches may be used, it has been customary heretofore to forin the rotor winding out of coils so that the rotor conductors may be connected directly inseriesand only a smallnumber of terminals brought out for short-circuiting. This coil construction is more expensive than what is known as the squirrel-cage construction, which is employedjn motors which start without resistence in circuit, and in which the rotor Winding is composedk simply of bars ell connected together at opposite ends through short-eircuiting end-rings. This simple con# struction has presented diiiculties heretofore when it has been desired to have a resistance in the rotor circuit at starting, since a switch adapted tor short-circuit individually,a large number of bars is necessarily complicated. By my invention it is possible, without a complicated starting switch, to 4employ a squirrel-cage construction and yetto obtain the advantages of a coil-wound rotor with respect to starting with a resistance in the rotor circuit.

My invention consists in providing the motor with a rotary casing containing a conducting fluid, such as mercury, adapted to be distributed around the periphery of the casing by centrifugal force as the motor speeds up, and so arrangingf` the casing and under load shouldv 'here a resistance included in the rotor cir cui-t, if itis' desired to prevent it from drew j' ing a heavy starting current, and this .re-

lowresistance short-circuit tor all the conductors individually, as in a squirrel-cage winding, when the vmotor is up to speed. l'. 'further provide ineens for retarding the peripheral distribution of the mercury so es to obtain the proper time element i'n operation.

More specically stated, my invention consists in providing the motor with a casing carried by the rotor and formingr a high re sistance short-circuit for the rotorA conductors and a conducting'tluid ip"the easing adapted to form e low-resistance shoitcircuit for the conductors when distributed around the inner periphery of the casing by centrifugal force.

My invention comprises a number of other features which will best be .understood by reference to the accompanying drawings, in

AFigure l shows a side elevation, partly in eross-section, of a rotor provided` with an automatic starting device in accordanceewith my invention; and Fig. 2 shows an end elevation in cross-section, of the starting device.

In the drawings A represents the stator of the motor, which carries the usual primary Winding,l a. Brepresents the rotorstructure which carries the rotor conductor b, which consists ot bars supported in the usual menner in slots in' the laminations at the periphery of the rotor structure. The. bars are all'directly connected to each other at one end by short-circuitiug rin-gs C. At the other end of the rotor the rotor oars are short-eircuilted `by a member D, which is bolt ed to the rotor structure, endwhich serves as one of the clamping rings for holding the rotor laminati-ons in place, and which is'in the form of an annular easing. The rotor conductors b extend through the peripheral wall d of the casing close to its inner side. This wall, or, if it isnotinsulated from the 'rest of the casing, the entire casing, is made i of high resistance metal, such, for instance, as manganese copper, and -forms a highv resistance short-circuit for the rotor conductors atv starting. Within the casing Dis supported an annular trough E, which is carried on pins e close to the peripheral wall of the casing D. This trough is provided with a re' strieted opening c in its periphery, es shown in Fig. F, ,i`nl1`ig. 2, represents'a conleo lherinore, the device, iu uddition to being :uitonmtic in its action at starting, also .frutoninticully reacts itself for starting' again when the current is cut ott7 since, :is the rotor slows down7 the niercury Will collect nt the lower portion of the casing.

lVbut. I cluiin ns new, and desire to secure by Letters Patent olE the United Sintes, is,

l. ln :in induction motorU n. rotor having u squirrel enge w hiding, u closed casing carried :it one end of the rotor engaging the ends oit :ill the conductors of Huid Winding and Serving aS u high resistance end ring for Suid Winding, und n conducting iluid in said Caising adapted when distributed uround the inner periphery of seid casing tofurnish an additional low resistance shortcircuit for Suid conductors and to :1ct electrically :1S e. low resistance end ring therefor.

ln un induction niotor, u starting switch comprising n roluny casing', u Conducting fluid therein, connections whereby the rotor conductors ure Shorhcircuited by the distriried within the cuing; The n-'zills of the trough E are arranged. 'to extend inward :i dielunce substuntiully equal to the depth of the inercury in the eosin casing is at rent, :is shown in Fig. l, so that when the crisi v et reet nearly ull the nier cury is contained in the trough; only :i enroll portion being;` outeide ol the troiufh und in contact with 'the peripheral wall d.

is the niotor te, the fluid F diS- tributed by centrifugal 'to 1e around the :ixunulur trough E. )it Stnrtng, the rotor conductors are short-circuil'ed only bythe high resistance casing, the Smell uniount of inercury outside oi the trough short-circuiting only u few conductora, und not materially I allecting the operation. litter the mercury is distributed uround the trough ll by cen triliugul force, it begins Lo pues, outward through the restricted ooeninc' c, und to distribute itselt' around the inner periphery o' `the ending. ln this way, in :ulditionul Shortn i uxiinuni when the ducting lluiihsuch es mercury, which is our circuit or low resituncc i -i produced lor the bution or the fluid around the inner periphrotor conductors through n lun' rc ietnnce ery ol Suid casing by centrifugal 'torce7 und formed by the mercury itself, und also by the ineens 'tor rcturding the distribution of the trough E, which inode of low-resistance tluid.

In un induction niotor7 u :starting switch comprising' u casing carried by the rotor and foi-nung :1 high resistance short-circuit for the rotor conductors, Luid :i conductingfluid in said casing adapted to forni :i low-resistance Shortfcircuit. `for Suid conductors when distributed uround the inner 'periphery of Suid easing by centrilugzilforce.

4. ln un induction motor, u Starting Switch comprising u casing carried by the rotor und forming u higlrresistnnce Short-circuit Jor the rotor coi'iductors, u conducting fluid in Suid casini; udnoted to forni n low-resistance Short-circuit 'tor Suid conductors when distrilnited around the inner periphery or' Suid rinsingv by ccntritugnl force, und ineens for returding the distribution oi said luid.

5. ln :in induction motor, LI-Sturting switch coniprieing u casing i by the rotor und material, :unl which is placed in electrical connection, with ull the conduct/orsA Z; by the mercury iillinu the ,eprice between the trough und the peripheral wull (Z. 'l he tiine Which elztpses between the starting oi the motor und u completo short-circuiting of ell the' rotor conductors by the mercury is deterniincd by the si' or' the restricted opening c', und consequently uuty readily be mede Whitt.- ever desired. l he cmiductorn` 7 :ire pli ced clone enough to the inner side ot the w ll l so 'that the reintuncc- :e little riferiti-,r thun if the mercury were in du ort commet with these ronductors? und thie ronntrui ion rcudera it unnecessary to innige u, fluid-tight joint betneenveuch conductor und the cunin would Abe necesnr) iii the cond nctors extended into the clnnnber within the casing so us to coinc into direct contuct with the mercury.

.lf lthe casingis built up ol' seperate ports, for eonienicuce in uesenibliuq, {luid-tight joint between the parte "nay be obtained b finishing the contact Surface "I i curing thorn toim her, ;'o\ fj their: mixture oi: lithorge und glycerin. The con struction of the onda-ing may, oi course, be varied as desired.

1With a motor :is thus constructed the udi'untuges of a c iiln'onn,d rotor :irc obtained, as reguds the amount or stnrtingrurrent taken, with the cheupuess :rofl simplicity oit construction of e squirrel-enge. Furthern'ioriu since the starting device is entirely l :iutoinuticT the niotor muy be installed in un l inucceusible position end Started by nierely l closing u switch in the p 'imftry circuit loczited wherever is most convenient. Furcarried forming n high-resistance short-circuit 'jor the rotor conductors, said conductors extending into the peripheral wall of sind casing close to its inv-er side, and :i conducting fluid in Said :using adapted around the inner periphery of Suid raining by centrifugal force unil thereby to torni n lowresistunce Sliort-circuit for the rotor conductors.

G. ln an induction motor, :i storting switch comprising' u casing carried by the rotor und formingA u high-resistance short-circuit for the rotor eomluctors, seid conductors extendinginto the peripheral wall of Suid casing close to its inner side` u coinlucting fluid in Suid casing adopted to be distributed Around the inner periphery of Suid casing luy-centrifugal Jforce and thereby to forni u lowto be distributed 'annular trough for the 1otor confor retarding the distri resistance short circuit ductors, and means bution of said iuid.

7 In an induction motor, a starting switch comprising a casing carried by the rotor and forming a high-resistance short-circuit for the rotor conductors, a conducting fiuid in said casing adapted to be distributed around the inner periphery of said casing by centrifugal force and thereby to form a loW- resistance short-circuit for the rotor conductors7 and an annular trough carried Within said easing` an d having a restricted opening in its periphery. 1

8. in an induction motor, a starting switch comprising a casing carried by the rotor and forming a high-resistance short-circuit for the rotor conductors7 a conducting fluid in said casing adapted to be distributed around `the inner periphery of-said casing by centrifugal force and thereby to form av low-resistance short-circuit for the rotor conductors, and an ot' low pressure material carried Within and close tothe inner periphery of said casing and having a restricted opening in its periphery.

S). In an induction motor, a starting switch comprising a easingearried by the rotor and forming a high-resistance shortecircuit for' the rotor conductors, a conducting tluidin said casing adapted to be distributed around the .inner'periphery-of said casing by centrifugal force and thereby to form a 10W` resistance short-circuit for the rotor conductors, and an annular. trough carried Within said casing, its sides extendingin- Ward a distance substantially equal to the maximum depth of said fluid in said casing when said casing is stationary, said trough having a restricted opening in its periphery.

In an induction motor, a starting switch comprising a casing carried-by the rotor and forming a high-resistance .shortcireuit for the rotor conductors, said conductors extending into the peripheral Wall of said casing close to its innerside, a conductingluid in said easing adapted to be distributed around the inner periphery of-said i l l l I l to form a lowresistaiice short-circuit for the rotor conductors, and an annular trough for low-resistance material carried Within and close to the inner periphery of said casing and having a restricted opening in its periphery.

l2. In an induction motor, a laminated i'otor body, an end-ring for clamping the aminations in place in nular casing, conductors carried by the rotor connected at one end to said-ring, vsaid 4ring being adapt-ed to form a high-resistance short-circuit for said conductors, and a conducting fiuid Within said end -ring adapted to be distributed around its inner periphery by centrifugal force and thereby to form a low-resistance short-circuit for said conductors.

13. In an induction motor, a laminated rotor body, an end-ring for clamping the laminations in place in the form of an annular casing, conductorsv carried by connected at one end to said ring,

the form of'an anshort-circuit for said conductors, a conductcasing by centrifugal force and thereby. to

form a low-resistance rotor conductors,

carried within said stru-.ted opening in short-circuit foi; alid an annular trough casing and having' a reits periphery. f

11.111 an induction motor, a starting switch comprising a casing carried by the ing fluid Within said end-ring adapted to be distributed around its inner periphery by centrifugal force and thereby to form a lo'w- 90- resist-ance short-circuit for said conductors and means for. retarding the distribution ot said Huid.

14. In an ,induction motor, a laminated rotor body,

an end-ring for clamping the laminations in place in the form of an annular casing, conductors carried by the rotor and extending into the peripheral ivall of said casing, said Wall being ada ted to form thigh-resistance short-circuit tor said eon- 100 ductors, vand a conducting fluid Withinl said casing adapted to be distributed around its inner periphery by centrifugal force and thereby to -form a low-resistance short-cir cuit for said conductors.

15.111 an induction motor, a laminated rotor body, an end-ring for clamping the laminations in place in the form of an annular casing, conductors carried by the rotor and extending into the peripheral Wall of said casing, said wall being adapted to form a high-resistance short-circuit for said conductors, a conducting tluid within said casing adapted. toA bedistributed around its inner periphery by centrifugal force and thereby to 'orin a low-resistance short-circuit for said conductors, and means for retardingl the distribution of said iiuid.

ln witness whereof, l have hereunto set my hand this 13th day of February, 1906. 120

CONWAY ROBINSON.

lVitnesses:

BnNJAMiN B. Hur' HELEN Oni'onn.

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