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July 2, 1946c M; P. WINTHER ELECTROMAGNETIC APPARATUS Filed March 12. 1945 ' 6 sheets-sheet 1 ,EV H f55/ ii" vIk! 9.9 97 49 FIG . ML K )x July 2, 1946. M. WINTHER 2,403,4214 ELECTROMAGNETIC APPARATUS Fíled'March 12, 1945 /l " l 6 Sheets-Sheet 2 July 2, 1946. M. P. WINTHER _ 2,403,421 ELECTROMAGNETIG APPARATUS Filed March 12, 1945 6 Sheets-Sheet 3 July 2, 1946. M. P. wlNTHER 2,403,421 ELECTROMAGNETIC APPARATUS Filed March l2, 1945 6 Sheets-Sheet 4 July 2, 1946. l M. P. WIN'THER ELECTROMAGNETIC APPARATUS 2,403,421 July z, 1946. A M. P. WINTHER 2,403,421 ELECTROMAGNETIG APPARATUS Filed March 12, 1945 n 6 Sheets-Sheet 6 NOE 2,403,421 Patented July 2, 1946 n . UNITED STATES “PATENT oFFl-cE ELECTROMAGNETIC APPARATUS Martin P. Winther, Waukegan, nl., assigner to Martin P. Winther, as trustee Application March 12, 1945, Serial No. 582,301 1 - - 18 Claims. This invention relates to electromagnetic ap paratus, and with regard'to certain more spe (Cl. 18S-104) 2. Referring now moreparticularly to Fig. l, there ciiic features, to high-speed, high-capacity dy is shown at numeral I a platform, upon which are mounted pedestals _3 and 5 (Fig. 2). The namoineters and the like. pedestals 3 incorporate bearing structures which _ - ~ Among the several objects of the invention may be noted the provision of a water-cooled, eddy-current. dynamometer adapted to operate safely at high speeds and to absorb heavy loads; the provision of a dynamometer’of the class de scribed which will pass large volumes of cooling water for high rates of energy absorption with out introducing parasitic unsteady torque; the completeness. Each of thes'e bearings (note the one of Fig. 3 for example) consists' in enclosing members 1 and 9 wherein are supporting bear ing rings II and I3 for supporting outer bearing flanges I5 of a ring gear I1, the rim of the latter provision .of a machine of the class described which employs a rotor and a method of cooling the ring gear containsthe outer race 2| of a roller bearing 23. it adapted to >minimize distortions under high bearing 23 is carried on a neck l21 of a rocking ' are not new herein but which are described for extending radially between the bearing rings II and I3 (see also Fig. 5). An inner hub I9 of The inner- race 25 of this rotor speeds; and the provision of a machine of stator S, to be described hereunder in detail. this class which is simple and economical to build As indicated in Fig. 5, the teeth 29 of the gear and maintain. Other objects will be in part ob I1 mesh with a pinion 3l on a countershaft 35 vious and in part pointed out hereinafter. supported in outboard bearings 33. The counter 'I'he invention accordingly comprises thev >ele 20 shaft 35 carries a sprocket 31 connected by a chain 39 with a sprocket 4I on the shaft 43 of a ments and combinations of elements, features of construction, and arrangements of parts which worm-gear speed reducer 45. The speed Areducer will be exempliñed in the structures hereinafter 45 is continuously driven from a motor 41. The described, and the scope of the application of ' purpose of this type of bearing for each neck 21 25 is to maintain a continuous slow rolling of the which will be indicated in the following claims. In the accompanying drawings, in which is bearings 23 so that each does not continuously illustrated one of- various possible embodiments load one spot on the races 2| and 25, as would be substantially the case if these bearings did of the invention, ‘ . Fig. 1 is an end view of one component dy-not continuously progress~` It will be appreciated narnometer unit embodying features of the in 30 from what follows that each neck 21, although vention; it'rocks slightly, is essentially stationary during Fig. 2 is a left-side view of Fig. 1; operation, the anti-friction bearing being basic Fig. 3 is a partial longitudinal section of one ally necessary for the purpose of preventing loss unit on a slightly enlarged scale with respect to of torque applied through the stator S to a suit 35 able dynamometer measuring scale. that of Fig. 1; Fig. 4 is a vertical section taken online 4-4 The stator S will now be described. It consists of Fig. 3i I of opposite heads 49 and 5I.- Since the interior construction of the head 49 also exemplifies the Fig. 5 is a horizontal section taken on line 5-.-5 of Fig. 1 but on a further enlarged scale; 40 interior construction of the head 5I, only the Fig. 6 is a diagrammatic plan view of several former will be described in detail so far as in combined units embodying other features of the terior parts are concerned. Referring to Fig. 3, invention; and ' I it will be seen that the neck 21 is on a bell 28 Fig. 7 is a detail section taken on line bolted to the head 49. In addition there is bolted of Fig. 6. -' . 45 to the inside of the head 49 a sleeve bearing 53 which supports a gudgeon 55 of a rotor R, also Similar reference characters indicate corre sponding parts throughout the-several views of to be described. A labyrinth assembly 51 is car the drawings. ‘ ried on the inside of the head 49 and has annular ` Increasing sizes of engines to be tested at high labyrinth dams 58 engaging portions toward the speeds are presenting increasing problems in the 50 rotor R of the gudgeons 55. One or more oil leads dynamometer test. ileld. By means of the appa , 59 having flexible exterior connections lead oil- ratus herein described 15,000 H. P. may be ab sorbed at from 8,000 to 12,000 R. P. M. This is done with relatively simple and safe apparatus requiring a. minimum in control organization. to the bearings 53y and an overflow of pipe 92 carries off excess oil and' foreign material. A flexibly connected air port 8| serves to apply pressure to resist incipient lleakage into the 9,403,431 . ing shown at 04. ‘ _ The connections 91 pass through the outer cyl inder 0l through openings |01. Each water ring 0l is provided with a lower drain pipe as indicated at |00. They are also joined by means of preferably nonmagnetic rings 1l.` although the latter may be magnetic. since the iiux leakage lost through them is ordinarily negligible. Members Il, I1, 00,»1I, 13 and 1l p have less resistance against bending than a single . one of the same capacity. Thus another source of parasitic torque on the stator is minimized. The outer periphery of each head such as 4I is bolted as indicated at 83 to an outer cylinder Il. Within endwise rings B1 this cylinder car ries an inner magnetic cylinder 80 made up of a series of rings 33 and 10. These rings are Joined by .pocket-forming rings 1| and 13 also composed of magnetic material. 4 bility. The reason for making the water con nections 0B inv multiple, is that such connections labyrinth packing l1, the outlet for this air be 10 The outer casing BB isprovided in its bottom with relatively large openings ||| through which extend drain pipes .i I3. Pipes -| I3 are in com munication with openings Il! in the bottom of the inner cylinder composed by the rings 00 and 13. The means for carrying water from the end 40 and necks 21. liquid manifold rings 00 to the outlets H5 is as Within each annular recess formed by the follows, referring to Figs. 3 and 4. At intervals rings 1| and 13 is a peripheralLv wound neld coil along the bottom of the rings 80 and 10 are 11. One coil is shown in Fig. 3 but it will be un derstood that toward the opposite end of the 20 supporting cross bridge plates ill.“ Each clears the bottoms by means of an opening H0. Each machine is another similar coil symmetrically in effect forms an arch or bridge for accommo located with respect to a central plane. dating free liquid ñow beneath it. Each is per Welded to the top arcuate portionsy (but not forated to carry axially disposed water tubes |2 |. the bottom) of the rings 80 and 10 are longi-' Each tube |2l is axially slotted as at |213 adia tudinal magnetic teeth 8| and 83. These extend are suitably welded to form a double-walled hollow cylindrical rotor unit having the heads . radially (Fig. 4). As indicated at 35, their ends extend under the coils 11. 'I'hese teeth are widely spaced and their ends are tapered down preferably to provide for approximate ilux satu cent to the rotor cylinder l1 so as to project a sheet of water against that cylinder. `Notches which hold tubes |2| in the plates ||1 allow the issuing sheet to be continuous throughout the . ration from their ends. The toric flux neld gen 30 length of the cylinder I1'. Axially disposed deilectors' |25 are used above erated by one of the coils 11 is indicated in Fig. 3 the lower nest of tubes I2| thus formed. A de by dotted lines. It engenders. for example, a fiector |21 is also used between groups of five of series of north poles in the teeth Il within ring these pipes and located at the bottom of the 03 and a series of opposite south poles in teeth bridge plates li'l.I These deilectors |25«and |21 33. If desired this polarity may be reversed by serve also as stiffening members between the changing the 'direction of current through the bridged supports Il'l. From Fig. 4 it will be coils 11. This iiux traverses'the drum I1 which noted that the bridge supports ||1 are welded forms the main part of the rotor R. Thus if the to the inside of the rings 88 and 10. rotor, which is also magnetic, is caused to rotate. A. single additional pipe |20 is used axially eddy currents are engendered therein. and the 40 between the two uppermost groups of teeth 0| resulting reactive nux neld applies torque to the and 83, the same being fastened to these by stator S through the teeth 0| and I0. This means of welded web plates |3|. This pipe, like torque is in a proportion to the energy trans the pipes I2I, is axially slotted adjacent the formation accomplished by the heating of the cylinder 01 by the eddy currents. 45 cylinder 01 to project liquid thereon. It is pref~ The cylinder 01 is solid and preferably made It has a solidv stepped con nection 30 with the gudgeon il. The gudgeon Il also has a solid connection with‘the shaft 0| ' which extends from the machine for attachment 50 of generator steel. of an engine to be tested or for attachment to another dynamometer unit as will be described. erable that all of the pipes I2| and |20 be non magnetic.` such as of brass. so that they do not act as short circuits for the flux field issuing from the teeth Il. All of the pipes I2I and |28 at'opposite ends of the machine are fastened into header rings |33 which form suitable inlets for the pipes from the ring manifolds 9B. The stepped connection 30 cooperates with a From the above it is evident that if water un stepped labyrinth 33 formed on the inside of an endwise water ring Il. The cooperating steps 00 55 der suitable pressure (which may be low) is in troduced into the end rings 8l it will progress to and 03 act as an additional liquid dam. v the pipes |2l and |29 and issue in radially di A header ring 0B is attached at each end of the inner cylinder 0l formed by the rings Il ' rected, longitudinal sheets against the rotor cylinder I1. It will be noted however that by far and 1l. the outer cylinder 05 overlapping 0I end wise. Each ring 0l includes at the top a pair of 60 the greatest volume of water issues from the ten pipes at the bottom of the machine against the water inlets 31 having ilexible connectors Il under side of the cylinder I1 and that only a reaching to the opposite end of the machine. small amount, one-tenth (for example) by com These sets of nexible connectors l! have con parison, issues from the other pipe |29 against nections III with water manifolds |03. The the upper side of the cylinder. This is an im manifold at the end of the machine correspond portant feature of the invention, taken in con ing to the pedestal 3 is carried on the enclosures 1, l. The manifold |03 carried at the other end ' nection with the use of a'limited number only of flux-concentrating teeth 0| over the upper of the machine (Fig. 2) is located upon a bear arc of said cylinder 01 and in connection with ing assembly Ill, supported on the pedestal I. This bearing assembly |30 is similar to the one 70 free drainage facilities. The space below and between the rotor R and stator S is of'suiiicient above pedestal 3 and also includes a bearing ro tating apparatus such as shown in Fig. 5. The volume to accommodate a pool of coolant without the rotor dipping therein. purpose of thus oppositely connecting the mani The cylinder _01 is heated strongly under the AVfolds |03 is so that the flexible connections 33 may be as long as possible for maximum flexi 75 teeth 3|, due to the heavy eddy currents en 2,403,421 - gendered therein. 6 5 The heated surface then quickly sweeps down into a voluminous flood of coolant (water for example) opposite the lower pipes |2I. . This large flood of coolant may safely ' be applied because in this region there are no radially extending teeth which might otherwise tend to cause churning, unsteady, parasitic, hy draulic action of the dynamometer. The excess of coolant descends to the bottom of the hollow four units of the type above described coupled in tandem. This tandem coupling allows for a large increase in speed because capacity is in creased without undue increase'in diameter of the cylinders 81. With smaller cylinders such as 81 higher speeds are better tolerated. The exterior of the apparatus will now be de scribed in connection with Figs. 2, 6,1 and 7. vEach outer case or stator S is provided with cylinder composed by the rings 89 and 10 -and 10 opposite pads |42 for attachment on one or the passing underneath the bridge supports ||1, other side of_a suitable arm for yreaching to passes to the outlets II5. weighing apparatus for measuring force at a On the upper region-„of the cylinder 81, where the flux-concentrating teeth 8| are located, known radius for calculating torque. Opposite The defiectors |25 and |21 tend to> baille the . Fig. 6 an arm on a pad |42 is diagrammatically ' threaded sockets |43 are also employed for ap there is very little water applied. This addi 15 plication in one of said sockets of a suitable arm tional water is only suilicient to prevent excessive (extending in the opposite direction from theheating in the cylinder 81 under the teeth 8|. Y arm in pad |42) to support a dead weight. In streams of water below the cylinder 81 and to shown in dotted lines at |45 and the weighing prevent them from progressing upward. 20 scale at |41. ' Water is carried off from the outlets ||5 to On the opposite side is shown in dotted lines y the pipes I I3 into a hollow base |35 of which the an arm |49 threaded into a socket |43 and sup platform I is the top. Relatively large open porting a dead weight I5|. By this means the ings I31 are applied in the top I movably to amount of weighing that needs to be done by accommodate the pipes |I3, and the latter are 25 means of the scale |41 in order to measure a connected to the top I by fiexìble connectors |39 given torque is reduced by the amount of torque so as to prevent vapor and thevlike from issuing supplied by the dead weight I5|. The amount from the base |35. In the base |35 is a suitable , of the weight I5| of course willbe known, 'and ' coolant sump I4I from which the received hot its moment plus that applied by the scale |41, water is pumped to cooling apparatus, or if 30 will give the total moment applied to the case. desired for recirculation or may be thrown away In Fig. 2, is shown a cover |53 which is located to waste. The base also contains whatever aux over an inspection opening. iliaries may be required, such as an oil pressure Coupling means are used between successive lubricating system etc. units in tandem as shown in Figs. 6 and '1. Cou It will be seen from the above that the cylinder pling is accomplished by providing at each end of -81, the stepped down portion 89, gudgeon 55 and a given unit two pairs of pads |55 (see also Fig. 2) for receiving extension trusses. The trusses on also favors high rotative speeds in addition to each side between adjacent units are indicated at the diameter of the cylinder 81 being kept down |51 and |59 in Fig. 6. All of the trusses |51 and las much as possible 4while relying upon length 40 |59 are of general triangular shape, each having increase for increased capacity. feet |6| for application to one of the pair of pads ' It will be noted also that the stator S is built |55. Each |51 ends in a tongue |63. Each truss up by welding from various Cylinders, rings and |59 ends in a clevis |65. When bolted into posiw the-like. This provides a substantial amount of 4tion the tongues |63 lie withinthe mouths of empty space between rings 59, 10, 13 and the 45 the clevises |65. Adjusting bolts |61 in opDO outer cylinder 65, Hence a rigid double site sides of the clevises |65 serve properly to barreled stator structure is obtained accommo eliminate lost angular motion. The rotor shafts dating the coil 11 and an ample flux path with ' 9| are connectedby couplings 92, as shown be- » shaft 9| are all made integral and solid. This out increasing the weight of the stator unduly. tween the units in Fig. 6. By this means undue flux wandering is also pre 50 It will beobserved that if desired, added dead vented since it is confined entirely to the inner barrel 59, 1|, 13, 10. In this respect it is im portant that the ring 13 be separated from the outer cylinder 65 by means of an air gap so that there will not be a loss of fiux from the flux circuits to outer cylinder 65. y The rings 58 and 1|| joined by the rings 1| and 15 form an inner waterproof structure joined to the outer cylinderv 65 by means of the spacing rings 31. 'I'his construction provides good rigid ity without commensurate increase of weight in` the stator. It also provides recessed spaces for the coils 11 which needuto be located behind the lweights such as I5| may be applied to each of v the units in the series. More arms such as |45 and scale |41 may also be used. But it is usually preferable to use one arm and one scale on a more or less central one of the umts and also to apply a single arm |49 and single dead weight |5I to said more or less central unit. Through the truss couplings all of the torque from al1 units may be weighed from one. The break line in Fig. 6 indicates that more units may be inferred to be in the line of two shown therein. ' . The endmost unit, which is shown at the right teeth.8|, 83. The hollow heads 49 with the con in Fig. 6, may have its shaft provided with a tained but separate headers 95 favor a light 65 splined slidable crown coupling |59~for engage construction without sacriñce of strength. ment and disengagement with a cooperating` Each unit (one of‘which has been above de crown coupling |1| on the shaft |13 lof a'motor scribed) is arranged'to be coupled in co-axial |15. Theípurpose _of this is to provide means for tandem with another so thatv a line of units may turning the rotor for cleaning operations and the be used together, as shown by Fig. 6. Fig. 6 70 like, independently of any driving engine, or to shows, for example, two units coupled together rotate said rotor for other than testing> pur (one fragmentary). but it will be understood that poses.V ì three, four or more may be coupled for unitary From the above itfwill be seen that- I have pro action in tandem. The capacity above quoted, vided small-diametered dynamometer means namely, 15,000 H.- P. absorptive capacity is for 75 which _is safe athigh speeds for absorbing large 2,403,421 8 7 ward the rotor and into relatively close proximity amounts of energy and for accurately measuring the resulting torque for computing horsepower. 'I'he system employed lends itself to indennita increase in capacity without increasing rotor sizes by multiplying the -units used __in tandem. with the latter to form 'ilux gaps, said poles being ` spaced throughout an arc over only upper por tions oi' the rotor. a field coil in the stator lor generating a flux ileld interlinking the stator and the rotor through said poles, axially located con duit means between the rotor and the stator hav It is also reversible. the opposite pads il! and sockets |43 being for the purpose of properly op positely applying the weights and scales under such circumstances. Thus it is particularly adaptable to a wide range o! cases where dyna ing openings directed toward the rotor for flood ing it with a coolant, and means for introducing 10 coolant into said conduit means. the space‘be mometers are required. In any multiple of units the action is smooth because of the large reduc tion in parasitic hydraulic torque which in the ordinary machine builds up vibrations. Such vi brations in tandem units would become periodic and the present means minimizes this contin gency. , - While the invention is disclosed in connection tween the rotor and the stator adjacent the con duit means being of suil‘icient volume to accom modate a relatively large pool o! coolant. 4. A dynamorneter comprising a rocking stator, an eddy-current rotor therein, rotary liquid seal ing meam between and near the ends of the rotor and the stator, said stator and rotor being sub stantially radially spaced, axial flux-concentrat ing polar teeth extending from the stator toward with a dynamometer application, it will be un derstood that it is also applicable to similar ap-` 20 the rotor and into close proximity with the iat ter, said teeth being peripherally spaced through paratus, such as slip couplings. brakes and the out an arc only over upper portions o! the rotor, like. . a field coil in the stator for generating a flux In view of the above, it will be seen that the held interlinking the stator and the rotor through several objects o! the invention are achieved and said teeth, axially located conduit means between other advantageous results attained. the rotor and the stator having openings directed As many changes could be `made in the above toward the rotor for flooding it with a coolant. constructions without departing from the scope means for introducing coolant into said conduit of the invention, it is` intended that all matter means, the space between the rotor and the contained in the above- description or show_n in the accompanying drawings shall be interpreted stator adjacent the conduitmeans being of sui as illustrative and not in a limiting sense. ticient volume to accommodate a relatively large I claim: circulating pool of coolant without the rotor dip _ l. Apparatus of the class described compris ing inner and outer relatively rotary members’ ping therein, and at least one axial conduit means , over the upper arc of the rotor in the space be ` which are substantially radially spaced. flux-con centrating poles extending from one of the >members toward `theother and into close proximity tween it and the stator and between said teeth which pipe is also open toward the rotor for pro Jecting coolant thereon. the amount of cooling medium applied to the rotor from said last-named conduit being substantially less than the volume spaced throughout an arc over only upper por tions o! said inner member, a ñeld coil in one of 40 oi cooling medium applied below the rotor from said mst-named conduit means. the members adapted to generate a flux held in 5. A dynarnometer comprising a rocking stator. terlinklng the members through said poles, axial a rotor within the stator and having rotary liq conduit means located between said members and uid end seals with respect thereto, said rotor and having openings directed against one o! the mem bers for flooding it with a liquid coolant. means 45 said stator having relatively large radial spac ing, axially extending magnetic pole means at for introducing coolant into said conduit means, tached to the rotor and extending toward only the space between said members being sumcient . upper arc portions oi the rotor, ileld means in to accommodate beneath the inner member a re1 the stator generating a iiux field interlinking ‘ atively large pool of coolant without -the rotor 50 the stator, the rotor and said axial poles, coolant dripping therein. l pipes axially located in the space between the 2. Apparatus of the class described comprising rotor and the stator, headers in the stator, said inner and outer relatively rotary members which pipes having open ends communicating with said are substantially radially spaced. iiux-concen headers and having openings along their length trating poles extending from one of the members directed toward the rotor for amply flooding it toward the other and into close proximity with with coolant, said pipes being located around the latter, said poles being peripherally spaced the lower arc of the rotor in radial space suill throughout an arc over only the upper portion of cient to form a substantial pool of coolant with said inner member, a ileld coil in one of the mem outthe rotor dipping therein. . bers adapted to generate a nux neld inter-linking 6. A dynamometer comprising a rocking stator. the members through said poles. conduit means a rotor within the stator' and having rotary liq located between said members and having open with the latter, said poles being peripherally ings directed against one of the members for ?oodlng` it with ,a liquid coolant, that portion oi the conduit ‘means which supplies most of the coolant being located between said members throughout an arc under only lower portions of the inner member. the space between said mem bere being suiiicient to accommodate beneath the inner member and in the outer member a rela tively large pool of coolant without the inner 70 member dipping therein. 3. A dynamometer comprising a rocking stator. . uid end seals with respect thereto, said rotor and said stator having relatively large radial spac ing, axially extending magnetic pole means at tached to the stator and extending toward only upper arc portions of the rotor, annular field means in the stator generating a toric flux ileld interlinking> the stator. the rotor and said axial poles, a plurality of coolant pipes axially located in the space between the'rotor and the stator. annular headers in the rotor, said pipes having open ends communicating with said headers and having openings along Vtheir lengths directed to an eddy-current rotor therein. said stator and rotor being substantially radially spaced. nux- - ward the rotor for flooding it with coolant. the ccncentratingpclcsextendingtromtbestatortc 75 numberotplpesapplyingthegrsatcramountct 2,408,421 _ coolant being located under the lower arc of the rotor, the space between said lower arc of the rotor and that of the stator being suflicient to carry a substantial pool .of coolant without the rotor dipping therein. . 10 tor with their ends in close proximity to the rotor, said rotor having endwise portions extend ing from the stator, endwise coolant seals be ytween the'stator and the rotor, liquid headers carried at opposite ends of the rotor, coolant 7. A dynamometer comprising a composite conduits -extending between communications rocking stator, said stator consisting of an outer with said headers and located ~in- the space be wall and a spaced internal wall, the latter having tween the stator and the rotor and having cool-_ ant iiooding openings directed toward the lat axial inwardly directed polar teeth and being provided with at least one outwardly extending l() ter, the conduits supplying most of the coolant lying in a peripheral region outside of that of peripheral recess, an Iannular field coil in said said polar'teeth and therebelow, and a peripheral ¿ recess, a rotor located within the stator and sub stantially spaced therefrom radially, said rotor field co-il supplying a toric iiux ñeld interlinking having endwise portions extending from the sta the stator, rotor and polar teeth. 12. A dynamometer comprising a rocking sta tor, endwise coolant seals between the stator and tor, said stator consisting of an outer sleeve and the rotor, annular coolant headers in the vends a spaced internal compositesleeve, the latter be of the stator, and coolant pipes extending be ing provided with at least one outwardly extend tween .communications wi'th said headers and through the space between the rotor .and stator. ing peripheral recess, an annular field coil in said 8. A dynamometer comprising a composite recess, a rotor located within the stator, said ro tor having endwise portions extending from the rocking stator, said stator consisting of an outer wall and a spaced internal wall, the latter having stator, endwise seals between the stator and the axial inwardly directed polar teeth and being pro rotor, and flux-concentrating teeth extending vided with‘at least one outwardly extending pe from the inner sleeve toward the rotor, the ra ripheral recess, an annular field coil in said re dial spacing between the rotor and said inner cess, a rotor located within the stator and sub sleeve being substantial, axially located pipes be stantially spaced therefrom radially, said rotor ~ tween the inner sleeve and the rotor having having endwise portions extending from the sta openings for impinging coolant against the rotor, tor, endwise coolant seals between the stator and said stator having at least one hollow annular the rotor, annular coolant headers in the ends 30 header with which said pipes communicate for receiving coolant. of the stator, and coolant pipes extending be tween communications with said headers and 13. A dynamometer comprising a rocking sta through the space between the rotor and stator, tor, a rotor vlocated within the stator, said rotor said polar teeth extending into cio-se proximity having endwise portions extending from the sta to the rotor surface. ` tor, endwise seals between the stator and the ro 9. A dynamometer comprising a composite tor, flux-concentrating polar teeth extending rocking stator, said stator consisting of an outer from the inner sleeve toward the rotor, an an wall and a spaced internal wall, the latter hav nular field coil providing a flux ñeld interlinking ing axial inwardly directed polar teeth and be the rotor, stator and polar teeth, the radial spac ing provided with at least one outwardly extend 40 ing between the rotor and said inner sleeve being ing peripheralV recess, an annular field coil in substantial, axially located pipes between the in said recess, a rotor located within the stator and ner sleeve and the rotor having openings for im substantially spaced therefrom radially said ro pinging coolant against the rotor, said stator tor having endwise portions extending from the having hollow annular endwise headers for cool stator, endwise coolant seals between the stator ant with which said pipes communicate, flexible and the rotor, annular coolant headers in the feed lines connected to `said headers respective ends of the stator, and coolant pipes extending ly and extending above the stator in opposite di between communications with said headers and rections, each feed line receiving its coolant from through the space between the rotor and stator, a point at the end of the rotor which is opposite said polar teeth extending into close proximity 50 to the end at which the feed line is connected to to the rotor surface, most of the pipes lying in ` its respective header. a peripheral region outside of that of the teeth 14. A dynamometer comprising a rocking sta and therebelow. ' tor having inwardly directed polar teeth, a ro 10. A dynamometer comprising a rocking sta tor within the stator and substantially spaced -tor having inwardly directed polar teeth, _a rotor therefrom radially, said teeth extending from the within the stator and substantially spaced there stator with their ends in close proximity to the from radially, said teeth extending from the sta rotor, said rotor having endwise portions extend tor with their ends in close proximity to the ro ing from the stator, endwise coolant seals be tor, said rotor having endwise portions extend tween the stator and the rotor, liquid headers ing from the stator, coolant seals between the 80 carried at opposite ends of the rotor, a plurality stator and the rotor, liquid headers carried by of coolant pipes extending between communica the stator, coolant conduits extending between tions with said headers and located in the space communications with said headers and located between the stator and the rotor and having in the space betweenvthe stator and the rotor coolant flooding openings directed toward the and having coolant flooding openings directed 65 latter, the pipes supplying most of _the coolant toward the latter, the conduits which supply most lying in a peripheral region outside of that of of the coolant lying in a peripheral region out said polar teeth and therebelow, and a peripheral side of that of said polar teeth and therebelow, -ileld coil supplying a torio flux field interlinking and a peripheral field coil supplying a toric flux the stator, rotor and polarteeth. field interlinking the stator, rotor and polar 70 15. A dynamoineter comprising bearing ped estals, a hollow stator mounted to rock in said 11. A dynamometer comprising a rocking sta pedestals, a rotor having bearings in the stator tor having inwardly directed polar teeth, a rotor and having end portions extending therefrom, within the stator and substantially spaced there coolant-receiving means at opposite ends of said >`from radially, said teeth extending from the sta 75 stator, separate flexible coolant supply pipes at teeth. , ' 1l moan: tached to said coolant-receiving means vrespec 12 K volume being distributed adjacent the lower arc tively, coolant-supply headers mounted upon said of therotor, and flux-concentrating poles pro pedestals, each ilexible coolant supply pipe which jecting from the inside of the stator into close proximity with respect to the rotor over upper larcuate portions thereof, and at least one annu lar field coil carried by the rotor and supplying a ilux circuit through the rotor, poles and stator. 18. Apparatus of the class described compris ing inner and outer relatively rotary members vwhichA are substantially radially spaced, iiux concentrating poles extending from one oi the members toward the other and into close prox is connected to one receiving means communi eating with the header on the pedestal which is at the opposite end of the stator. 16. A dynamometer comprising a stator, an annular field coil in the stator, a rotor within the stator passing through said coil, said stator and rotor being amply spaced radially, flux-con ’ centrating teeth in the ilux circuit oi' said coil and extending from the stator and into close proximity to the rotor surface at upper arcuate imity with the latter, a field coil in members .adapted to generate a iiux portions of the latter, endwise coolant .headers in the stator, coolant pipes connecting said head 15 linking the members through said poles being peripherally spaced with ers, said pipes having coolant openings adjacent the rotor and at its lower arcuate portions for one of the field inter poles, said a majority of them located in a predetermined upper arc be tween the adjacent peripheries of the rotary projecting coolant against the rotor, said pipes members, - thereby leaving in the remaining arc be being in the space between the rotor and the stator and connecting said headers, and supports 20 tween said adjacent peripheries a space which is for the pipes at intervals along 'the stator but less obstructed by poles than is the space in said bridging its bottom portion to allow for a sub' upper arc, means for spraying coolant onto the in ner rotary member primarily from said relative stantial pool of coolant, said stator having bot tom outlet means from the pool of coolant. ly unobstructed space, said outer member hav 17. A dynamometer~ comprising a hollow cy 25 ing coolant outlet means from said relatively un lindric stator, a cylindric rotor therein and-am obstructed space which -will let out coolant from phr spaced therefrom radially, annular coolant the outer member, the arrangement being such that no pool of coolant in said relatively unob headers at the ends o! the stator, coolant pipes connecting said headers and having coolant pro structed space touches the rotor. Jection openings directed toward the stator, the number oi' pipes carrying the greatest coolant MARTIN P.