CN1272244A

CN1272244A - Device for rotating electric machine

Info

Publication number: CN1272244A
Application number: CN98809644A
Authority: CN
Inventors: 马茨·莱昂; 古纳·凯兰德
Original assignee: Asea Brown Boveri AB
Current assignee: ABB AB
Priority date: 1997-09-30
Filing date: 1998-09-29
Publication date: 2000-11-01
Also published as: EP1020009A1; WO1999017429A1; NO20001596D0; JP2001518778A; SE9703551D0; NO20001596L; PL339561A1; CA2305428A1; AU9291798A; SE513057C2; SE9703551L; BR9812407A

Abstract

A device and a method for thermally insulating a rotating electric machine comprising a stator (1), wound with a high voltage cable (11), and a rotor (17), whereby the machine is provided with a thermal insulation (20, 60, 70, 90) in the air gap between the stator (1) and the rotor (17).

Description

The device that is used for electric rotating machine

The present invention not only relates to high voltage rotating machine, synchronous machine for example, but also relate to the dual-feed motor, the application of asynchronous converter level, outer utmost point motor and synchronous flow motor, and also have alternating current machine, they are mainly as the generator in the power plant that produces electric power.More particularly, the present invention relates to the cooling within the air conduit, and between the rotor and stator in such motor, carry the device of cooling agent by cooling duct.

Such motor conventionally designs for the voltage in the 15-30kV scope, and 30kV is commonly referred to be the upper limit.This means with regard to generator, must generator is connected with power network by transformer, transformer makes voltage be elevated to the electric pressure of power network, i.e. electric pressure in the 130-400kV scope.The present invention's preparation under high pressure promptly mainly surpasses the voltage use down of 10kV.Typical operation scope according to motor of the present invention can be the voltage of 36kV to 800kV.

High voltage rotating machine has cooling system usually, and to force cooling motor, high pressure is the voltage above 10kV and up 30-35kV here.There are two kinds of dissimilar air cooling systems in cooling for routine: radially cooling and axially cooling, in radially cooling off, air also further guides by the radial conduit in the rotor by wheel hub, and in axially cooling off, air is blown into pole gap by axial fan.

High voltage rotating machine is made of the stator that is provided with groove usually, and these grooves are stator slot, wherein arranges AC winding or stator winding.These grooves are generally rectangle or trapezoidal.Between groove, form so-called stator tooth.Each winding is made up of a plurality of coil groups that are connected in series, and each coil groups is made up of a plurality of coils that are connected in series.The different piece of coil is appointed as coil side and end winding, and coil side is the part that is arranged within the stator, and the end winding is the part outside the stator.A coil is made up of one or more conductors, and conductor is become together at height and/or width.One deck thin insulating is arranged, for example the epoxy/glass fiber between each conductor.Coil is by coil insulation and groove electric insulation, and coil insulation is promptly prepared the insulation of tolerance motor rated voltage over the ground.Various plastics, lacquer and glass fiber material can be used as insulating material.Usually, use so-called mica tape, it is the mixture of mica and duroplasts, produces to providing resistance to partial discharge specially, and partial discharge can destroy electric insulation apace.By around coil, twining the several layers mica tape, coil is applied insulation.Make insulation impregnating, and make coil side scribble paint based on figure thereafter, to improve and contacting of stator on every side, stator is connected with earth potential.Stator can be made of the quadrature or the directed steel of lamination, or can constitute by other amorphous or based on the material of powder.Also have some motors, wherein the electric power winding is arranged in the rotor, and the magnetic field winding is arranged in the stator.

For the cooling of large ac machines, often use gas cooled to stator and rotor.Usually make gas pass through cooling duct and radially passed stator, cooling duct is formed by the separator that radially separates.Separator is the unit of the laminated core of stator branch into about the 30mm axial length, and they are the high and thick straight line rectangle steel element of 2mm of 6mm normally.

Can arrange gas circulation in the motor according to different principle.Hydroelectric generator is a kind of multipolar generator, it is characterized in that big stator diameter and convex pole.Rotor in the hydroelectric generator can design has radially cooling duct, so that air is radially in rotor and stator delivered inside.Usually also make gas be pressed into the air gap vertically with the fan at motor two ends, it turns to 90 ° then, radially leaves by the stator conduit afterwards.Turbogenerator has seldom several magnetic poles, and for example 2 or 4 magnetic poles is characterized in that the rotor that substantial cylindrical constitutes.Rotor conductor in the turbogenerator is often by the gas cooled of carrying within the axial pipe, and these conduits are connected with conductor.The gas of heating is discharged in the air gap by radial conduit, and these radial conduit are often concentrated to central authorities.Stator in the turbogenerator is divided into different cooling chambers, and wherein the direction of gas stream can change, so that cold air can be pressed into the air gap in some chamber, and hot-air can be discharged from the air gap other chambers.Some turbo-dynamo is used so-called reverse cooling, and this means rotor fan makes gas from the air gap sucking-off, rather than air is pressed into the air gap.Be favourable like this, because in such a way, stator is air cooled by cold air rather than hot rotor.So the rotor fan blade is arranged on the top of rotor back-up ring, rather than be installed in vertically after the rotor back-up ring.

Cooling air can be made up of surrounding air, but surpasses under the 1MW at power, uses the closed cooling system with heat exchanger usually.At turbogenerator with approximately reach in the large-scale synchronous compensator of 400MW, use hydrogen-cooled usually.This cooling method still replaces air as cooling agent with hydrogen to work with the similar mode of the air cooling with heat exchanger.Hydrogen has better cooling capacity than air, but encounters difficulties aspect sewing in sealing and supervision.In order to constitute partitioning portion, punched cores dish one deck is arranged on the top of another layer, then form the cooling duct in the rotor usually.

The objective of the invention is to realize a kind of cooling system that is used for electric rotating machine, the high pressure in this electric rotating machine is used for from 10kV to the network voltage rate range.Such electric rotating machine will directly be connected with power network without intermediate transformer.This novel electric rotating machine has some characteristics, compares with conventional motor, has satisfied the specific (special) requirements to cooling system.

Above-mentioned purpose is realized that by device according to the present invention the characteristic of this device such as claims limits.

By using the High-Voltage Insulation electric conductor, this electric conductor is called high-tension cable hereinafter, they have and the used similarly permanent insulation of power transmission cable (for example XLPE cable), then can make the voltage of motor be increased to such grade, and it can directly be connected with power network without intermediate transformer.Therefore conventional transformer can omit.With routine techniques relatively, this concept requirement is wherein arranged the groove in the stator of high-tension cable dark (because voltage is higher, bring insulation thicker and umber of turn is more).The distribution that this means loss is different with conventional motor, and the cooling with regard to stator tooth produces new problem again like this.

Being used for insulated electric conductor of the present invention or high-tension cable and being flexible with flexible, and is the type that more is described in detail among WO 97/45919 and the WO 97/45847.The other narration of this insulated electric conductor or cable can be found in WO 97/45918, WO 97/45930 and WO 97/45931.

Therefore, in device according to the present invention, winding is preferably such type, and it is identical with the type of cable that those have the solid extruding insulation, and these type of cables are the type of cable that is used for distribution now, for example XLPE-cable or have the cable of EPR insulation.Such cable comprises an inner wire that partly is made of one or more strand, the interior semi-conductive layer around this conductor, a solid insulating layer and the outer semiconducting layer around this insulating barrier around this semi-conductive layer.Such cable is flexible, and this point here is important characteristic because according to the technology of device of the present invention mainly based on winding system, wherein winding is formed by the cable that assembly process is bent.The crooking ability of XLPE cable is usually corresponding to the radius of curvature of the about 20cm of cable of 30mm diameter, and the radius of curvature of the about 65cm of cable of 80mm diameter.In should using, the term crooking ability is used to refer to flexible about four times of arriving cable size of winding, is preferably eight of cable size and arrives duodenary radius of curvature.

Winding should keep its characteristic, even when it is bent, or when it stands thermal stress or mechanical stress during operation.It is extremely important that here each layer keeps their adhesion each other.The material behavior of layer here is conclusive, particularly their elasticity and the relatively hot coefficient of expansion.For example, in XLPE cable, insulating barrier is made of cross-link low-density polyethylene, and semi-conductive layer is made of the polyethylene of mixed carbon black and metal particle wherein.Be absorbed as the cable radius change fully by the caused change in volume of temperature fluctuation, and because the elasticity of relative these materials has more small difference between the thermal coefficient of expansion in the layer, so radial expansion can take place under the situation that does not lose layer-to-layer adhesion.

The above-mentioned material combination should be thought just as an example.Other combination natures of realizing rated condition and semiconductive condition also belong to scope of the present invention, and semiconductive promptly has 10 ^-1-10 ⁶Within the ohm-cm scope, the resistivity of 1-500ohm-cm or 10-200ohm-cm for example.

Insulating barrier for example can be made of solid thermoplastic material, cross-linked material or rubber, solid thermoplastic material for example has low density polyethylene (LDPE) (LDPE), high density polyethylene (HDPE) (HDPE), polypropylene (PP), polybutene (PB), poly-methylpentane (PMP), cross-linked material for example has crosslinked polyethylene (XLPE), and rubber for example has ethylene propylene rubber (EPR) or silicon rubber.

In can be identical stock with outer semiconducting layer, the still wherein particulate of hybrid conductive material, for example carbon black and metal dust.

The mechanical property of these materials, particularly their thermal coefficient of expansion seldom are subjected to the influence of mixed carbon black whether or metal dust, i.e. mixed carbon black or the metal dust of these materials to realize requiring according to conductance required for the present invention comparatively speaking.Therefore insulating barrier and semi-conductive layer have roughly the same thermal coefficient of expansion.

Ethylene-vinyl acetate copolymer/acrylonitrile-butadiene rubber, butyl grafted polyethylene, vinyl-acrylate copolymer and ethylene-ethyl acrylate copolymer also can constitute the suitable polymer of semi-conductive layer.

Even when during as various layer basic, wishing that also their thermal coefficient of expansion is roughly the same with dissimilar materials.This is the situation of the above listed material of combination.

More than listed material have relative excellent elasticity, have E＜500MPa, preferably＜the E modulus of 200Mpa.This elasticity is enough to make that any minute differences between the material coefficient of thermal expansion coefficient radially is absorbed flexible in the layer, so that crack-free or any other damage and occur, and layer is not thrown off each other.The layer in material have elasticity, and the layer between adhesion at least with material in the weakest point have same intensity.

The conductance of two semi-conductive layers is enough to make along the current potential of each layer about equally.The conductance of outer semiconducting layer is enough high so that electric field is included within the cable, but enough low again, with not can layer vertically owing to induced current causes sizable loss.

Therefore, two semi-conductive layers constitute an equipotential surface separately in fact, and the winding that constitutes these layers will make electric field be enclosed within it haply.

Certainly, do not hinder one or more other semi-conductive layers of arrangement in insulating barrier.

In motor according to the present invention, the insulation of winding by with the high pressure solid insulated cable in identical materials, for example crosslinked polyethylene (XLPE) is formed.These materials do not have the durability temperature more identical with the insulation of conventional generator, and the insulation of conventional generator can be dealt with about 130 °-155 ℃.The characteristic of XLPE just changes at 70 ℃, and absolute ceiling temperature is 90 ℃.This means that air cooled temperature rise for common 40-60K, only allows 10-20K.Mean very large air containment like this, cause very big ventilation loss, and this is the significant drawback of generator.

In addition, compare with conventional motor, in motor according to the present invention, stator tooth has more elongated shape.The long stator tooth is very responsive to the tangential magnetic force on the flank of tooth that acts on face air gaps.In having traditional gas cooled stator of cooling duct radially,, make between the separator that is stacked in cooling duct crooked owing to the pressure that acts on the lamination causes.The bending of lamination causes the tangential rigidity of lamination to degenerate greatly, and this will be the problem of an especially severe in New-type electric machine.In such long stator tooth, the very big danger that inferior tangential rigidity causes resonating and high amplitude is vibrated causes high sound level and puncture so again in long-play.

Therefore be better with this novel stator of water cooling.Stator can be produced singlely like this, and need not be divided into the steel assembly that is separated by cooling duct radially.Rotor can be conventional rotor fully, and it is usually gas-cooled meaning it like this.So the problem that occurs is that the hot-air that may surpass 110 ℃ from rotor makes the surface of stator faces air gap become warm to such degree, so that temperature sensitive stator winding is in the risk of overheating.This is a special problem relevant with turbogenerator.

This problem of novel turbogenerator can be owing to this fact, and promptly heat transfer coefficient is very high in the air gap, brings a large amount of hot-fluids to go into stator tooth like this.In addition,, mean that like this magnetic flux density increases gradually, so the electromagnetic consumable in the stator tooth is near the air gap maximum because stator tooth is tapered to the air gap.Because stator tooth is long like this,,, just be difficult to the torrid zone is walked so do not obtain sizable temperature gradient radially producing high relatively thermal resistance.Also be difficult to arrange enough cooling ducts at the narrowest place of stator tooth.And because eddy current causes, being arranged in the loss ratio of the cable of close air gap, to be positioned at other local cables big, and eddy current is because the result of slot leakage flux and producing in copper conductor.

If in the air gap between rotor and stator, arrange the thermal insulator of heat-obtaining insulating concrete cylinder form, then can address these problems.Radial distance between the inner surface of air gap thereby indication stator core and the outer surface of rotor core.In most of embodiment, cylinder will be connected with the stator solid, and heating is avoided on the surface of protection stator.And in a possibility embodiment, cylinder has cooling duct, so that the additional cooling of stator is provided.The unnecessary length with stator of the length of cylinder is corresponding, and can be short or longer.

The common embodiment of cooling duct requires to make hot-air flow through the inner rotator conduit vertically, and be discharged in the air gap by rotor fan in the rotor, and this air gap is greatly about the centre of motor shaft to length.The rotor air is drawn by the radial stator conduit then usually.If use this solution,, also some stator conduits must be arranged naturally even stator is water-cooled so.So cylinder is made a plurality of parts or is made a plurality of electroplating holes, so that the stator conduit is uncovered.In this case, on the stator winding that should in radial conduit, not be capped, and be exposed on the stator lamination in the hot gas, use thermal insulator.Because hot rotor air is concentrated to the middle body of air gap,, the line shaft of cylinder lacks so making than the axial length of stator to development length.

The air gap unnecessary formation cylinder that insulate, but can form by casting compound or a plurality of axial dielectric plate, make them deadlocked on stator.

If rotor fan turns to other direction, hot-air can pass through air gap sucking-off, promptly so-called reverse cooling so.The advantage that possesses this cooling is to need not center conduit in stator, produces the buckling problem of plate and thermal insulator like this.The reverse cooling of known type that it should be noted that gas circulation discord turbogenerator is corresponding, because there is not the stator conduit.Coil-end cause the insulating concrete cylinder should be longer like this, because also will be protected from hot-air than stator.

Below with reference to accompanying drawing, narrate the present invention in more detail.

Fig. 1 represents the part schematic diagram in the diametric(al) cross section of rotary electric machine.

Fig. 2 represents the sectional view according to high-tension cable of the present invention.

Fig. 3 schematically illustrates the sector of electric rotating machine.

Fig. 4 schematically illustrates according to the first embodiment of the present invention.

Fig. 5 a schematically illustrates according to a second embodiment of the present invention.

Fig. 5 b schematically illustrates a third embodiment in accordance with the invention.

Fig. 6 represents the cross section according to first embodiment of any one cylinder in Fig. 4, Fig. 5 a or Fig. 5 b illustrated embodiment.

Fig. 7 represents the cross section according to second embodiment of any one cylinder in Fig. 4, Fig. 5 a or Fig. 5 b illustrated embodiment.

Fig. 8 represents the cross section according to the 3rd embodiment of any one cylinder in Fig. 4, Fig. 5 a or Fig. 5 b illustrated embodiment.

Fig. 9 represents the cross section according to the 4th embodiment of any one cylinder in Fig. 4, Fig. 5 a or Fig. 5 b illustrated embodiment.

Figure 10 represents the cross section according to the 5th embodiment of any one cylinder in Fig. 4, Fig. 5 a or Fig. 5 b illustrated embodiment.

Figure 11 represents the end-view according to the embodiment of Figure 10.

Fig. 1 represents a kind of motor that has rotor 17 and stator 1.The major part of stator 1 is made up of stator frame 2 and stator core 3.As shown in the figure, stator winding forms so-called coil terminal assembly 8 in the both sides of stator 1.

In large-scale conventional motor, stator frame 2 is usually with welded steel structured design.In large-size machine, stator core 2 is also referred to as cores pile in layers, and the so-called steel lamination with 0.50mm designs usually, and these steel laminations are assembled into the assembly with about 50mm axial length, and are separated by the midfeather that constitutes about 5mm air trunking each other.Yet air trunking is removed in motor according to the present invention.In large-size machine, the structure of each piece of stamping parts is by suitable big punching press fragment 9 being arranged together, forming ground floor, stack each subsequent layer thus, assigning to carry out with the whole disc portion of structure stator core 3.

Fig. 2 represents the sectional view according to high-tension cable 11 of the present invention.High-voltage cable 11 comprises many strands 12 with circular cross-section, for example is copper (Cu) line.These strands 12 are arranged in the central authorities of high-tension cable 11.Around strand 12, arrange first semi-conductive layer 13.The insulating barrier 14 that arrangement is for example insulated for XLPE around first semi-conductive layer 13.Around insulating barrier 14, arrange second semi-conductive layer 15.Therefore in should using, the notion of high-tension cable is not included in during the energy distribution usually the external shield around such cable.Shown in this figure is detailed, for this insulated electric conductor or cable, construct these three layers, when cable is crooked even so that their also adhere to mutually.Shown in cable be flexible, and this specific character is maintained at its life period.

Fig. 3 schematically illustrates the sector of this motor, and it has the fan sheet 9 of stator 1 and the rotor magnetic level 16 on the rotor 17 of motor.Also apparent, stator winding 6 is arranged in the interval 7 of taking from driving chain shape between each stator tooth 4.This figure represents that also stator core comprises the stator yoke of stator tooth 4 and formation outer yoke part 5.Stator and form by one in the stator winding 6 that is arranged in the high-tension cable, it is arranged in the interval 7 of taking from driving chain shape that forms between the stator tooth 4 that respectively separates.This conductor is only distinguished stator winding 6 in the drawings.And apparent in the figure, this high-tension cable progressively is divided into several sizes according to its radial position in stator 1.Each of stator tooth 4 inwardly stretches from outer yoke part 5.In addition, in the air gap between stator 1 and rotor 17, arrange a thermal insulation cylinder 20 that is connected with stator.

Fig. 4 represents to belong to the axial section of gas-cooled first embodiment of the rotor 17 of a motor, and this motor has liquid cooled stator, for example water-cooled stator 1.Cooling air thereby from rotor two side inflow air gaps 22 is then by at least one radial conduit 24 in the stator 1.On stator, connect a thermal insulation block piece of getting cylinder 20 shapes, and it is arranged in the air gap between stator and the rotor, so that make the stator winding insulation that is arranged in stator.Cylinder 20 is provided with exhaust apparatus 26, and it gets the shape in space between hole, otch or the part cylinder, so that cooling air is discharged by conduit 24 then radially by cylinder 20 dischargings.In addition, cylinder 20 can be divided into several portions cylinder 20 ', 20 ", thus cylinder allows cooling air from these part cylinders 20 ', 20 " between radial discharge.Similarly, make conduit 24 thermal insulations, so that the protection stator winding is avoided hot cooling air.

Fig. 5 a represents to belong to the axial section of gas-cooled second embodiment of the rotor 17 of a motor, and this motor has the stator 1 of liquid cools.Refrigerating gas thereby flow into rotor vertically radially flows out rotor then, and flows into air gap 22.Coolant from the air gap sucking-off of rotor both sides, is discharged by the coil-end part 28 of stator 1 each side vertically afterwards then.Even in the embodiment of this gas cooled rotor, stator also has thermal insulation cylinder 20, but because another gas flow embodiment, cylinder 20 does not have exhaust apparatus, therefore design singlely, thereby radially sealed, and make gas cannot radially flow through cylindrical wall.

Fig. 5 b represent one corresponding to Fig. 5 a different embodiment, difference only is that in the 3rd embodiment refrigerating gas is arranged to the air gap 22 of flowing through whole rotor 17 and whole motor vertically, promptly flows out at opposite side at a side inflow.

Cylinder 20 designs according to a plurality of embodiment, so that get the gas-cooled form according to Fig. 4, or as according to the gas cooled of Fig. 5, plays an insulation block piece.

According to Fig. 6, in first embodiment of cylinder 20, cylinder 20 designs with the tube portion 60 of the homogeneous that low thermal conductivity material is made.Armoured glass fibrous epoxy resin or polymeric material are the suitable materials of thermal insulation cylinder.This class material has the thermal conductivity of 0.3W/mK.

According to Fig. 7, in another embodiment of cylinder 20, cylinder 20 is designed to the cooling water pipe 70 that spiral twines.Cooling water pipe 20 thereby design have the square-section, so that relatively radially extend the discharge area that keeps big.According to present embodiment, cylinder can also design the cooling water pipe with circular cross-section, and their spirals around an extruding movement twine, and keep distance between each winding turns, make these pipes " pressing " after this, so that pipe obtains the tubular outward appearance of homogeneous.

Fig. 8 represents the 3rd embodiment of cylinder 20, and it is two-tube 80 that it is designed to spirality, is the combination according to the embodiment of Fig. 6 and Fig. 7, promptly the tube portion 60 of homogeneous by cooling water pipe 70 around.

Fig. 9 represents the 4th embodiment of cylinder, and it forms with axial cooling water pipe cylinder 90.Cooling water pipe 70 thereby in air gap 22, be arranged in parallel with stator tooth 44.

Figure 10 represents the 5th embodiment of cylinder, and it forms with the axial winding of tube portion 60 with homogeneous two-tube 20, and the tube portion 60 of homogeneous is twined by an axial arranged cooling water pipe 70, and it forms an outboard tube.

Figure 11 is illustrated in the circular cooling water pipe 70 within the part, and it is wrapped in around the tube portion 60 of homogeneous, forms two-tube 100 of axially winding like this.

In all embodiment comprising cooling water pipe, cooling water pipe can design has circle, ellipse or square-section, or gets the homogeneous drum forms, and cooling air is radially passed through.

Cylinder 20 is with from the very little distance of stator inner surface coaxial arrangement suitably, so that further improve the insulation in the air gap 22.Little space between stator and the cylinder may need to fill up insulating material, glass fibre cotton for example, but dispensable.Cylinder is in providing mechanical strength, and glass fibre cotton forms main insulating material.Cylinder 20 is too not thick, because go wrong when the rotor that has its back-up ring is inserted stator.Can respectively the have an appointment suitable thickness value of 5mm of cylinder and space.Can utilize different may selecting, for example cylinder be wedged in the air gap 22 coaxially, so that cylinder 20 is fixed in the stator with separator.

Claims

1. electric rotating machine, comprise rotor (17), it is characterized in that this motor also comprises the stator (1) that is twined by high-tension cable (11), this high-tension cable (11) has an inner wire that is made of one or more strand (12), this conductor by an interior semi-conductive layer (13) around, this semi-conductive layer by a solid insulating layer (14) around, and this insulating barrier (14) by an outer semiconducting layer (15) around, and be that this motor has a thermal insulator (20,60,70,90), be arranged in air gap between stator (1) and the rotor (17).

2. according to the motor of claim 1, it is characterized in that stator (1) is a liquid cools, and rotor (17) is gas-cooled.

3. according to any one motor in the claim 1 to 2, it is characterized in that the rotor coolant is arranged to the central authorities that inwardly flow to rotor (17) from each rotor-end vertically, flow through the air gap and flow through rotor central authorities both, then by thermal insulator (20,60,70,90) exhaust apparatus in (26) outwards flows through at least one radial conduit (24) in the stator (1).

4. according to any one motor in the claim 1 to 2, it is characterized in that the rotor coolant is arranged to the central authorities that inwardly flow to rotor (17) from each rotor-end vertically by rotor (17), and radially outwards flow into air gap (22), flow out by air gap (22) along two-way then.

5. according to any one motor in the claim 1 to 2, it is characterized in that the rotor coolant is arranged to from a rotor-end inwardly flows through whole rotor (17) vertically, promptly by air gap and the central authorities by rotor, the other end by rotor flows out then.

6. according to any one motor in the claim 1 to 5, it is characterized in that arranging a cylinder (20) in the air gap between stator (1) and rotor (17), so that between stator and rotor, play a thermal insulation block piece.

7. according to the motor of claim 6, it is characterized in that cylinder (20) is connected with stator (1).

8. according to any one motor in the claim 6 to 7, it is characterized in that cylinder (20) is designed to the cooling water pipe (70) that spiral twines.

9. according to any one motor in the claim 6 to 7, it is characterized in that cylinder (20) is designed to have the cooling water pipe cylinder (90) of axial arranged cooling water pipe (70).

10. according to any one motor in the claim 6 to 7, it is characterized in that cylinder (20) is designed to tube portion (60).

11. any one motor in 9 is characterized in that cooling water pipe (70) is installed in the outside of tube portion (60) according to Claim 8.

12. any one motor in 9 or 11 is characterized in that cooling water pipe (70) presents the square-section according to Claim 8.

13. according to any one motor in the claim 1 to 12, it is characterized in that cylinder (20) has exhaust apparatus (26), so that make cooling air can pass through stator (1) from radially discharging.

14. according to any one motor in the claim 1 to 12, it is characterized in that cylinder is divided into a plurality of part cylinders (20 ', 20 "), so that make cooling air can pass through stator (1) from radially discharging.

15. according to any one motor in the claim 1 to 12, it is characterized in that making whole cylinder (20) radially to seal, see through cylinder and make stator winding (6) heating so that prevent cooling air.

16., it is characterized in that tube portion (60) is by the made with low heat conductivity coefficient according to any one motor in the claim 10 to 15.

17., it is characterized in that tube portion (60) is by the polymeric material manufacturing according to the motor of claim 16.

18. according to any one motor in the claim 6 to 17, it is characterized in that cylinder (20) with and the inner surface of stator (1) have a space to arrange coaxially, and this space fills up insulating material, for example glass fibre cotton.

19., it is characterized in that making layer (13,14,15) and also adhere to mutually even be arranged to when insulated electric conductor or cable bending according to any one motor in the claim 1 to 18.

20. one kind makes the heat-insulating method of electric rotating machine, it is characterized in that this motor comprises the stator (1) and a gas-cooled rotor (17) of a liquid cools, stator (1) is twined by a kind of high-tension cable (11), this high-tension cable has an inner wire that is made of one or more strand (12), this conductor by an interior semi-conductive layer (13) around, this semi-conductive layer by a solid insulating layer (14) around, and this insulating barrier (14) by an outer semiconducting layer (15) around, this stator has an outer yoke part (5), stator tooth (4) inwardly stretches from this yoke part, and be to realize the thermal insulation between stator (1) and the rotor (17) by a thermal insulator being inserted in the air gap between stator (1) and the rotor.

21., it is characterized in that making cylinder (20) to be arranged in the air gap between stator (1) and the rotor (17), and be connected, so that between stator and rotor, play a thermal insulation block piece with stator (1) according to the method for claim 20.

22., it is characterized in that cylinder (20) prevents that also gas stream from crossing the coil-end on the one or both sides of stator (1) according to the method for claim 21.