JP2627780B2 - Rotor of variable speed induction motor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor of a variable speed induction motor having good torque characteristics and efficiency and easy speed control.

[Conventional technology and its problems]

One of the methods for controlling the speed of the induction motor is to change the power supply frequency. Although this method allows continuous and wide-range speed control, the frequency converter required by this method is expensive, and harmonics are generally used in the process of converting alternating current into direct current by the frequency converter and converting it back to alternating current. Waves and radio waves are generated, which may cause malfunctions of computers and other various electronic control devices or failures such as overheating of capacitors. Among them, measures are taken against harmonics by installing filters. Yes, but it is costly to install filters. Further, it has a drawback that the performance is generally insufficient at low speed.

Also, the method of controlling the speed by changing the number of poles of the motor is:
Even if the speed can be changed stepwise by converting the number of poles, there is a disadvantage that smooth speed control cannot be performed steplessly.

Also, in the method of controlling the speed by changing the voltage of the power supply,
On the other hand, speed control can be performed continuously, but there is a disadvantage that efficiency is deteriorated particularly in a low speed region.

The method of controlling the speed by changing the slip by changing the secondary resistance in the winding type motor is relatively easy and continuous speed control is possible, but on the other hand, the rotor winding is controlled externally via a brush and a slip ring. In order to insert a resistor into the circuit, maintenance is required due to wear of the brush, and the squirrel-cage induction motor has a problem that the speed cannot be controlled by changing the secondary resistance.

To deal with the above problems, for example, Japanese Patent Application Laid-Open
No. 2,290,052 discloses this technique, which comprises two sets of coaxially mounted rotor cores and two independent stator windings opposed to the rotor cores.
Pairs of stators, cage-type conductors that are commonly installed across the rotor cores and are short-circuited at both ends via short-circuit rings, and cage-type conductors between the two rotor cores. A high-resistance element that short-circuits the cage conductors at the center is provided.
It is a twin-core cage type motor that shifts the phase by 0 ° and feeds power in phase during operation after starting.However, the starting torque is increased by shifting the phase between the stator windings by 180 ° at the start to improve the starting characteristics. It is characterized in that it can be operated with normal torque characteristics by matching the phases of the stator windings during operation. Therefore, even if the effect of improving the startability is recognized, this motor cannot be used as a power source of a load requiring a shift because it is not a variable speed motor.

In the above-mentioned Japanese Patent Application Laid-Open No. 54-29005, in the transition from the start-up to the operation, the mutual feed circuits of the stator windings are instantaneously connected in series for the purpose of alleviating a shock due to a sudden change in torque. May be provided in one example, but in this case, the phase shift of the rotating magnetic field is zero.
It is limited to both the points ゜ and 180 ゜ and is not intended for shifting. In addition, the fact that the voltage applied to the stator is reduced to half by switching in series, so that the torque is reduced to 1/4 and the shift control is not possible at all, the gist disclosed in this publication is essential. It is clear from not aiming at shifting.

In short, Japanese Unexamined Patent Publication No. 54-29005 tentatively states "an intermediate step for switching the stator winding between a series connection and a parallel connection with respect to a power supply circuit". It's just a useless connection.

In addition, since there is no special configuration in connecting the conductors between the rotor cores with a resistive material, if the gears are shifted and operated for a long time with a phase shift other than 0 ° and 180 °, heat and centrifugal force will cause an effect. It has disadvantages such as damage to the rotor.

[Object of the invention]

The present invention has been made in order to improve the above-mentioned disadvantages of the prior art, and is disclosed in JP-A-54-29005 and JP-A-49-86807.
This publication seeks a unique torque characteristic that cannot be achieved by the summation of the publications described above. The speed control region can be set to any desired speed as a wide range and the speed control can be set in a stepless manner, and can be started with an arbitrary torque. Variable speed induction with excellent torque characteristics and efficiency over the entire speed range from the starting point to the maximum rotation speed, and excellent heat dissipation of the resistance material, strength of the resistance material, and strength of the rotor conductor. An object of the present invention is to provide an electric motor rotor.

The variable speed induction motor of the present invention is used by connecting to a single-phase or three-phase power supply or the like, and the rotor may be any of a normal cage, a double cage, a deep groove cage, a special cage, and the like. It can also be applied to those of the form

[Means for solving the problem]

In order to achieve the above technical object, the present invention relates to a method in which a plurality of conductors mounted on a plurality of rotor cores are connected to each other to form an integral rotor, A plurality of stators are arranged side by side on a machine frame at an outer peripheral portion facing the plurality of rotor cores which are axially attached at intervals, and the plurality of rotor cores not facing the plurality of stators. In the meantime, the plurality of conductors are short-circuited via a resistance material, and one of the plurality of stators is related to at least one of the plurality of stators. A motor provided with a voltage phase shifter for generating a phase difference between a voltage induced in a conductor portion of the rotor facing the stator and a voltage induced in the conductor portion of the rotor facing the other stator. The plurality of stators not facing the plurality of stators. The resistive material, which is short-circuited between adjacent conductors between the child cores, has a plate shape having a width in the direction in which the rotor conductors communicate, and projects from one connected rotor conductor to the outer periphery of the rotor between the conductors. Then, the outer periphery of the rotor was folded back into a U-shaped cross-section, connected to adjacent rotor conductors, and short-circuited between the rotor conductors, thereby providing a means for solving the problem. Further, as another configuration of the invention, a configuration in which a part of the resistance material is formed in a plate shape including a band shape is provided.

(Operation)

According to the present invention, when a phase shift occurs in the magnetic flux of the rotating magnetic field generated between the respective stators by an arbitrary means, the combined voltage induced in the rotor conductor changes according to the phase shift of the magnetic flux, and the rotation is changed. The rotation speed of the rotor can be arbitrarily changed by controlling the voltage induced in the slave conductor to increase or decrease.

By the way, since the plurality of conductors provided on the plurality of rotor cores are short-circuited via the resistance material, a current flows through the resistance material according to the phase shift, and a large torque can be obtained. However, if a current flows through the resistance material, heat is naturally generated, which causes a reduction in the strength of the resistance material and the rotor conductor. In addition, there is an influence of centrifugal force, and the strength between the rotor cores is particularly reduced. In addition, the higher the torque, the higher the temperature of the resistance material increases, which may cause melting of the resistance material itself or melting and destruction of the rotor conductor connected to the resistance material.

By the way, in the present invention, the resistance material connecting the adjacent conductors between the rotor cores not facing the rotor core is formed into a plate shape having a width in the direction in which the rotor conductors communicate, and is protruded from the outer periphery of the rotor. Since the outer peripheral portion was folded back into a U-shaped cross section, the length of the resistance material could be made sufficiently large, and the cross-sectional area of the resistance material could be made sufficiently large to obtain the same resistance value. For this reason, the surface area of the resistance material was increased, the heat dissipation was improved, the temperature rise of the resistance material could be suppressed, and the strength of the resistance material and the strength of the rotor conductor could be improved.

In the case where the resistance material is formed into a plate shape including a belt shape, the surface area of the resistance material is greatly increased, heat dissipation is significantly improved, the temperature rise of the resistance material is significantly reduced, and the resistance material is a rotor. Since the conductors have a width in the communicating direction and are connected, the strengths of the resistance material and the rotor conductor can be greatly improved. As a result, high torque can be obtained over a wide range of speed changes and a wide range of speeds.

In addition, a part of the resistance material connecting the conductors adjacent to each other between the rotor cores not facing the rotor core was protruded to the outer periphery of the rotor, and was folded back into a U-shaped cross section at the outer periphery of the rotor. However, between adjacent conductors means a portion that short-circuits one conductor to the next.For example, a short-circuit from one conductor to the next conductor without passing through the next adjacent conductor next to it. It includes the case where it is done.

〔Example〕

Embodiments will be described with reference to the drawings. Reference numeral 1 in FIG. 1 denotes a variable speed induction motor according to the present invention, which has the following configuration. (See FIGS. 1 and 2.) Rotor cores 2 and 3 made of an iron core are mounted on a rotor shaft 4 at an arbitrary interval, and the rotor cores are mounted on the rotor cores 2 and 3 respectively. One end of each of the plurality of conductors 5 is connected by short-circuit rings 6 and 7, and the other side of the plurality of conductors 5 is connected to the other side.
Were formed into a set to form an end portion 51. Further, the rotor 8 is integrally formed between the rotor cores 2 and 3 by connecting a conductor 55 to a pair of conductors, that is, an end 51 of the rotor cores 2 and 3 in a communicating manner. I do. The conductors 55 connected in a communicative manner between the rotor cores 2 and 3 are short-circuited via a resistor r, for example, a copper-nickel alloy, a nickel-chromium alloy, an iron-chromium alloy, and stainless steel.

The rotor cores 2 and 3 are provided with a plurality of ventilation drums 12 communicating with both side portions 10 and 11 of the rotor 8. A plurality of resistance members r project between the rotor cores 2 and 3 so that a part of the resistance members r protrude to the outer periphery of the rotor 8 and are folded back into a U-shaped cross section at the outer periphery of the rotor. Can be formed on the cooling body 13 as a cooling agitator. On both side surfaces of the resistance material r, a shielding plate 52 to which a heat insulating material for shielding heat generated by the resistance material r is provided.

Bearing plates 15 and 16 provided on both sides of a cylindrical machine frame 14 are integrally assembled with bolts 17 on both sides, and cooling impellers 19 and 20 are mounted on both sides of the rotor 8 to rotate. Both ends of the slave shaft 4 are supported by bearings 21 and 21 fitted to bearing plates 15 and 16, respectively, so that the rotor 4 is rotatable.

As shown in FIGS. 1 and 2, a rotating stator 31 having windings 22 and 23 applied concentrically to rotor cores 2 and 3 and a second stator 25 face each other. , A sliding bearing 26 is provided between the machine frame 14 and the rotating stator 31, and the slide bearing 26 is fixed to the machine frame 14 by a stop ring 28. Reference numeral denotes a fixed stator fixed to the inner wall surface of the machine frame 14. A gear is provided on the outer peripheral surface of one side of the rotating stator 31.
A drive unit 33 is fitted and fixed to the outer periphery of the machine frame 14.
29, a driving gear 36 is mounted on a small motor 35 for forward / reverse rotation, and a plurality of air outlets 39 are drilled around the outer periphery of the machine frame 14. The ventilation holes 40 are provided.

A space 66 formed between the rotor cores 2 and 3, the rotating stator 31 mounted on the slide bearing 26, the second stator 25, and the machine casing 14.
Formed in the ventilation drum 67, opened a plurality of openings in the machine frame 14 and communicated with the ventilation drum 67, and formed the plurality of openings in an arbitrary number of blowing ports 68 and exhaust ports 69 is there. A motor 72 mounted on a windmill 71 is mounted on a blower cylinder 70 to form a blower 73. The blower 73 is fixed to the machine frame 14 and the blower 73
The air suction part 74A of the air communication is connected to the air outlet 69 and the ventilation duct 67,
An air outlet 68 for introducing outside air from the other of the air outlets 69
The blower 70 has an exhaust portion 74B formed therein. In addition, a cooler, a condenser, a refrigerant gas,
Other various refrigerant devices may be connected directly or through a conduit.

Driving gear 36 partially inserted into machine frame 14 from opening 37
And a gear 33 fitted to the rotating stator 31 are engaged with each other, and a small motor 35 having a switch forming a driving device 29 and a rotating mechanism 30 including a gear 33 and a driving gear 36 are provided. The rotating stator 31 is connected to the rotating stator 31 so that the rotating stator 31 is rotatable, and the rotatable stator 31 that is rotatable relative to the second stator 25 fixed to the machine frame 14 is transferred to the voltage stator. Formed on phase device 100.

By the rotation of the rotor 8, the outside air is sucked into the machine frame 14 by the cooling impellers 19, 20 from the ventilation holes 40 formed in the bearing plates 15, 16, and the windings 22, The rotor core 2, the conductors 5, etc. are cooled and removed out of the machine frame 14 through the exhaust holes 39, and in the cooling impeller 20, excess air sucked by the impeller 19 is passed through. The fluid flows into the body 12 and the rotor core 2,
3 is cooled, the air sucked from the bearing plate 16 is combined with the air, and cooled by passing through the windings 23 and the second stator 25, and is discharged from the exhaust holes 39B of the machine frame 14 to be cooled. The function is stably applied to each of the rotor 23, the rotor cores 2, 3 and the conductors 5. Reference numeral 38 denotes a solenoid for controlling the movement of the projecting piece in and out.
Numeral 38 is attached to the machine frame 14 and its protruding piece is engaged with a gear 33 fitted to the rotating stator 31 so that the stator can be easily operated without necessity such as reaction of the stator when torque is generated. This is a stopper for preventing rotation.

As shown in FIG. 3, the winding stators 31 and the windings 22 and 23 each having a star connection are connected to the second stator 25 in series. That is, the terminals A, B, and C of the winding 22 of the rotating stator 31 are connected to the commercial three-phase power supplies A, B, and C, and the terminals a, b, and c of the winding 22 are connected to the winding of the second stator 25. The terminals A, B, and C of the wire 23 are connected, and the terminals a, b, and c of the winding 23 are connected by short-circuiting.

 The operation of the above configuration will be described below.

When current is supplied to the windings 22 and 23 from a commercial three-phase power source, a rotating magnetic field is generated in the rotating stators 31 and 25, and a voltage is induced in the rotor 8, and a current flows through the conductors 5 of the rotor 8 so that the rotor 5 8 rotates. When the amount of rotation of each of the second stators 25 with respect to the rotation stator 31 is set to zero, there is no phase shift in the magnetic flux of the rotating magnetic field generated in each of the stators 31 and 25. Since no current flows through the resistance materials r, which are the materials, they have the same torque characteristics as general induction motors.

Next, a case will be described in which the small-sized motor 35 is operated to rotate the rotating stator 31, and the rotating stator 31 is rotated by θ at the electric phase angle. The phases of the magnetic fluxes φ ₁ and φ ₂ of the rotating magnetic field generated by the rotating stator 31 and the second stator 25 are shifted by θ, so that the rotating stator 31 and the second stator 25 voltage _{1, 2} phase induced in ... is shifted by theta. Now, based on the voltage ₂ induced on the conductors 5 of the rotor 8 by the second stator 25, the voltage is set to ₂ = SE. Here, S is the slip, and E is the induced voltage at the time of slip 1. Voltage ₁ induced in the conductors 5A by the first stator 24 this time is _{1 = SEε ^jθ.}

(E = Induced voltage at the time of slip 1) FIG. 4 shows the rotor 8 when the resistance material r ... that short-circuits the plurality of conductors 5 ... is not mounted in the non-magnetic material core 9 part. This shows the relationship between the slip S and the active power P of the rotor input. The active power P is maximum when the voltage phase is θ = 0 °, and is smaller when 0 ° <θ <180 °. Becomes If the resistance and inductance of the conductors 5 are R and L and the angular frequency of the power supply is ω, the maximum of the active power P appears when S = (R / ωL).

Since the effective power P is proportional to the driving torque of the induction motor 1, the voltage induced on the rotor 8 is adjusted by operating the small motor 35 to rotate the rotating stator 31 with respect to the second stator 25. In addition, the speed of the rotor can be controlled steplessly.

Next, the resistances from the short-circuit rings 6 and 7 of the conductors 5 of the rotor 8 to the connecting members are R ₁ and R ₂ , and the inductances are L ₁ and L ₁ .
And L _2, the angular frequency of the power source was omega, if the resistance of the resistive material for short-circuiting the conductors 5 ... each of the r, electrically equivalent circuit of the rotor 8 becomes as shown in FIG. 5, reference numeral I _1, I _2, I ₃ shows a current flowing through each branch.

Next, when the circuit shown in FIG. 5 is converted into an equivalent circuit viewed from both stators 31 and 25, the circuit becomes as shown in FIG. 6, where R ₁ = R ₂ , L ₁
= L ₂ and θ = 0 °, I ₃ = I ₁ −I ₂ = 0, and no current flows through the resistor r. This means that when θ = 0 °, the torque T is equal to the value when there is no r. Therefore, when θ = 0 °, it has the same torque characteristics as the conventional induction motor.

Next, when R ₁ = R ₂ , L ₁ = L ₂ and θ = 180 °, I ₁ = −
I ₂ , I ₃ = I ₁ −I ₂ = 2I ₁ , and if the resistance of the rotor conductor is R ₁ = R ₂ = R in the conventional induction motor, the result is the same as that when R is increased to R + 2r. I have.

Next, the operation of connecting the windings 22, 23 wound around the rotating stator 31 and the second stator 25, respectively, in series will be described with reference to FIGS.

Since the windings 22 and 23 are connected in series, current flows between the windings 22 and 23 from the commercial three-phase power supply. Regardless of the difference in the capacitance, regardless of the difference, the magnitudes of the currents flowing through the respective windings 22 and 23 are equal, and therefore, the rotation of the rotor 8 Are fixed according to the action of equalizing the magnitudes of the currents induced in the conductors 5... And the difference in rotation between the rotating stator 31 and the second stator 25, that is, the phase difference generated in the magnetic flux of the rotating magnetic field. Child 3
1, 25, the current flowing through the conductors 5 of the rotor 8 becomes equal, and the vector difference current caused by the voltage phase difference between the stators 31, 25 is Due to the synergistic effect of the action of generating a forcing force that flows inevitably through the resistance members r, which form each of the plurality of conductors 5 as a connecting member, efficiency such as slip and torque characteristics shown in FIG. 7 is obtained. And a large torque can be output in each shift range, and even when the load is connected, it is easy to start up in each speed range. Or start-up with high output can be used arbitrarily, and can be optimally adapted to a power source that repeatedly starts and stops repeatedly. As described above, the speed change of the rotor 8 is performed by the rotation stator 31.
, The rotation speed of the rotor 8 can be arbitrarily changed only by controlling the current flowing through the conductors 5 of the rotor 8 to increase or decrease.

It should be noted that the magnitude of the current flowing from each of the rotating stator 31 and the second stator 25 in which the windings 22 and 23 are connected in series to the conductors 5 of the rotor 8 is different between the plurality of conductors 5. Resistance material r ...
.. Irrespective of the resistance value and slip of the resistance materials r..., Pθ (P = the number of pole pairs, θ =
Phase angle), (the ratio is Pθ =
(π becomes maximum and Pθ = 0 and becomes zero when Pθ = 0) If Pθ is constant, the slip and torque characteristics are the same as those when the secondary insertion resistance of a general wound induction motor is constant, and when Pθ is small, The ratio of the current flowing through the conductors 5 of the rotor 8 becomes small, and reducing Pθ has the same effect as reducing the secondary insertion resistance of a general wound induction motor. When the rated current is applied to both stators 31, 25, the rated current and rated torque characteristics of the maximum speed depend on the selection of the slip value and the design of the resistance value of the connecting material even if the phase difference θ is arbitrarily changed. Can be made to act substantially equally in each shift range. In addition, even if the rotating stator 31 and the windings 22 and 23 of the second stator 25 are connected in series, if the connecting members are not provided between the conductors 5. At some point, current hardly flows through the rotor conductors 5.

The rotor of the induction motor configured as described above will be described below with reference to FIG. 1 and FIG.

First, the rotor cores 2 and 3 are generally formed by laminating a silicon steel sheet and an electromagnetic steel sheet. More specifically, the rotor cores 2 and 3 are made of a plurality of silicon steel sheets whose both sides are treated with a phosphoric acid film. It is polymerized to form an integral rotor core. This silicon steel plate is provided with a plurality of conductor insertion holes.

As described above, the rotor cores 2 and 3 are further cast with aluminum, and the ends for welding the conductor 5 and the short-circuit rings 6 and 7 and the conductor for connecting the rotors by the so-called aluminum die casting method. The portion 51 is formed integrally at the same time.

Here, the end portion 51 formed by the casting is one end portion 51 formed of a plurality of conductors 5 formed in a plurality of conductor insertion holes similarly by casting. However, one end 51 may be formed for one conductor 5.

The rotor 8 is welded between the cast rotor cores 2 and 3 by welding the ends 51 and the conductors 55 formed on the rotor cores 2 and 3 to form the conductors 55 in communication. Form.

For the conductor 55 described here, copper, brass, stainless steel, copper-nickel alloy, iron or the like is used.

Further, the conductor 55 welded to the rotor 8 is short-circuited via a plate-shaped resistance material r having a width in the communication direction of the conductor 55, and the plate-shaped resistance material connected between the conductors 55 is short-circuited. r is protruded from the outer periphery of the rotor 8 between the conductors 55 and is folded back into a U-shaped cross section at the outer periphery of the rotor 8 and is fixed to the conductor 55 by welding. Here, the welding includes brazing. The term "projected and folded back into a U-shaped cross section" means that, for example, the resistance material r circumscribes the outer peripheral portion of the conductor 55a and protrudes toward the outer periphery of the rotor, and is folded back into a U-shaped cross section on an arbitrary extension. The resistance material r is circumscribed to the outer peripheral portion of the next conductor 55b adjacent to the conductor 55a, and repeatedly protrudes to the outer periphery of the rotor, and the resistance material r is a contact surface or contact between the conductor 55 and the resistance material r. It is welded at a point and fixed to the conductor 55.

Outside the above embodiment, for example, circumscribes the outer peripheral portion of the conductor 55a, further circumscribes the outer peripheral portion of the next adjacent conductor 55b, protrudes to the outer periphery of the rotor, is folded back into a U-shaped cross section on any extension, and again. The shape of repeating the outer peripheral portion of the conductor 55c adjacent to the conductor 55b, or the outer peripheral portion of the conductor 55a, circumscribes the outer peripheral portion of the conductor 55a, protrudes to the outer periphery of the rotor, is folded back into a U-shaped cross section on any extension, and Circumscribes the outer periphery of the next conductor 55b adjacent to the conductor 55a, and
A method that does not circumscribe the 55c but circumscribes the outer peripheral portion of the conductor 55d next to the conductor 55c and further protrudes to the outer periphery of the rotor can be easily considered.

The resistance material r is intended to increase its surface area and to improve heat dissipation and strength. Depending on the resistance value of the resistance material r, the resistance material r may have a plate shape.
In some cases, the width of the plate may be narrowed to form a strip, or a hole may be provided at an arbitrary position in the resistance material r.

With the configuration described above, a current flows through the resistance material r and generates a large amount of heat according to the phase shift caused by the voltage phase shifter when the variable speed induction motor according to the present invention starts and when a high torque is generated. However, as described above, it is projected to the outer periphery of the rotor and formed into a U-shaped cross section on an arbitrary extension to form a band-shaped or plate-shaped resistance material r, so that its surface area is increased, and heat dissipation is greatly improved. The strength of the resistance material and the strength of the rotor conductor can be improved.

〔The invention's effect〕

By pursuing the improvement of the torque characteristics and efficiency over the entire speed range from the starting point to the maximum rotation speed of the variable speed induction motor according to the present invention by the above configuration and operation, melting of the resistance material due to heat generation of the resistance material or In some cases, the rotor conductor was melted and broken.

However, a part of the resistance material connecting the adjacent conductors between the rotor cores is projected to the outer periphery of the rotor, folded back into a U-shaped cross section on an arbitrary extension of the outer periphery of the rotor, and the resistance material is strip-shaped. By using a plate-like thing containing
The heat dissipation of the resistance material, the strength of the resistance material, and the strength of the rotor conductor can be greatly improved. That is, by suppressing the temperature rise of the heat generated by the resistance material, the variable speed induction motor can obtain high torque in a wide range of speed changes and a wide range of speeds.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a variable speed induction motor according to the present invention, FIG. 2 is a front sectional view of FIG. 1, FIG.
The figure shows the relationship between rotor slip and active power, FIG. 5 shows an electric equivalent circuit of the rotor, FIG. 6 shows an electric equivalent circuit of the rotor viewed from the stator side, and FIG. FIG. 8 is a diagram showing the relationship between speed and torque when each of the rotor conductors is short-circuited by a resistance material and the windings wound on the stator are connected in series. FIG. 4 is a front sectional view of a rotor portion. 1 ... variable speed induction motor, 2,3 ... rotor core, 4 ...
Rotor shaft, 5 ... Rotor conductor, 6, 7 ... Short-circuit ring, 8 ...
Rotor, 10,11 ... Both sides, 12 ... Ventilator, 13 ... Cooling body, 14 ... Machine frame, 15,16 ... Bearing board, 17 ... Bolt, 19,20 ... Cooling Impeller, 21 ... bearing, 22, 23 ... winding, 25 ... second stator, 26 ... sliding bearing, 28 ... stop ring, 29 ... drive device, 30 ... rotating mechanism, 31 ......
Rotating stator, 35 ... small motor, 36 ... driving gear, 37
…… Opening, 38 …… Solenoid, 39 …… Outlet, 40 ……
Ventilation opening, 51… end, 52… shielding plate, 55, 55a, 55b, 55c, 5
5d ... conductor, 66 ... space, 67 ... ventilator, 68 ... vent, 69 ... vent, 70 ... wind turbine, 71 ... windmill, 72 ...
Motor, 73 …… Blower, 74A …… Air intake port, 74B ……
Exhaust port, r ... resistance material.

Claims (2)

(57) [Claims] A plurality of rotor cores attached to the same rotating shaft at arbitrary intervals and provided with a plurality of rotor conductors communicating with the plurality of rotor cores; A plurality of stators are formed on a machine frame, and a plurality of stators are arranged side by side on a machine frame at an outer peripheral portion facing the plurality of rotor cores, and the plurality of rotor cores not facing the plurality of stators. In between, the plurality of conductors are short-circuited to each other via a resistance material, and any one of the plurality of stators is associated with at least one of the plurality of stators. A voltage phase shifter for generating a phase difference between a voltage induced in a conductor portion of the rotor facing one stator and a voltage induced in a conductor portion of the rotor facing the other stator is provided. A rotor of an electric motor, wherein conductors adjacent between the plurality of rotor cores are provided. Are connected to each other in the form of a plate having a width in the direction in which the rotor conductors communicate with each other. A rotor for a variable speed induction motor, wherein the rotor is connected to conductors and short-circuited between rotor conductors. 2. The variable speed induction motor according to claim 1, wherein the resistance value of the plate-shaped resistance material protruding from the outer periphery of the rotor is changed by changing the width of the rotor conductor in the communicating direction. Rotor.