JPH01227692A - Variable speed induction motor - Google Patents

Abstract

PURPOSE:To accurately set a speed changing range to an arbitrary speed value from a low speed to high speed by rotating a stator with a speed detector in a variable speed motor having two stators. CONSTITUTION:A small-sized motor 35 is operated to rotate a rotating stator 31 thereby to rotate the stator 31 through a predetermined angle by an electric phase angle, thereby regulating a voltage induced in a rotor 8 to steplessly control the speed of the rotor. A speed detector and a controller (both not shown) are provided. The rotating speed of the rotor 8 is detected and compared with a set speed thereby to drive the motor 35 to become a set speed, thereby rotating the stator 31.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a variable speed induction motor that is applied to loads with reduced torque characteristics, such as fans and pumps, which have good torque characteristics and efficiency and whose speed can be easily controlled.

[Prior art and its problems]

In recent years, one method of generally controlling the speed of a general-purpose electric motor is to change the frequency of the power supply. While this method allows for continuous and wide-range speed control,
The frequency converter required by this method is expensive, and harmonics and radio waves are generally generated in the process of converting alternating current to direct current and then back to alternating current, which can cause computers, their electronic control systems, etc. This can lead to problems such as malfunction of equipment or overheating of condensers. Among these, harmonic interference can be countered by installing filters, but installing filters is costly. Additionally, they have drawbacks such as generally insufficient performance at low speeds.

Further, although the method of controlling the speed by changing the voltage of the power supply allows continuous speed control, it has the disadvantage that efficiency is poor especially in the low speed region.

In addition, the rotor of a general-purpose electric motor is formed by overlapping and connecting multiple silicon steel plates whose end surfaces have been treated with a phosphoric acid insulating coating such as carlite. Even in case C, where no insulation treatment was applied to the conductor insertion hole to be inserted, the current flowing back into the conductor did not flow into the conductor insertion hole, and no special treatment was required.

By the way, as an example of a conventional multiple stator electric motor, the one disclosed in Japanese Patent Application Laid-Open No. 54-19005 is known, and in this technology, two sets of rotor cores installed on the same axis are opposed to each other. A squirrel-cage type stator, which is installed in common across two sets of stators each having an independent stator winding, and the two sets of rotor cores, and which are short-circuited at both ends via short-circuit rings. A conductor and a high-resistance element that short-circuits the squirrel-cage conductors at the center of the cage-shaped conductors between the two sets of rotor cores, and winds wires on independent stators facing the rotor core. This is a twin-iron cage type mower that shifts the phase of the stator windings by 180 degrees at startup, and feeds power while matching the phases during operation after startup. By shifting the phase between the stator windings by 180 degrees, the starting torque is increased and the starting characteristics are improved. During operation, the phase between the stator windings is matched and the stator windings can be operated with normal torque characteristics. It is something.

Therefore, even if the effect of improving startability is recognized, this electric motor is not a variable speed electric motor and cannot be used as a power source for a load that requires speed change.

To briefly describe the technology disclosed in Japanese Patent Application Laid-open No. 54-29005, when transitioning from startup to operation,
For the purpose of alleviating the shock caused by rapid fluctuations in torque, one example is to provide an intermediate staircase that instantly connects the mutual power supply circuits of the stator windings in series, but in this case,
The phase shift of the rotating magnetic field is limited to both Oo and 18o degrees, and is not intended for speed change purposes. Moreover, by switching to series, the voltage applied to the stator is halved, so the torque is reduced to 1/4, and this makes gear change control completely impossible, which is the main point disclosed in this publication. It is clear from the fact that the purpose is not to change speeds, and although it is said that there is an intermediate step in which the stator windings are switched between series connection and parallel connection with respect to the power supply circuit, this series connection is not used for the purpose of speed changes at all. The connection is nothing more than a useless connection, and the speed cannot be controlled to any desired speed.Also, since there is no insulating material installed in the conductor insertion holes for inserting the conductors into the two sets of rotor cores, the stator When increasing the starting torque by shifting the phase of the windings, the current that flows back into the conductor leaks into the rotor core through the conductor insertion hole and is absorbed, resulting in a reduction in starting torque efficiency. Ta.

Furthermore, in Japanese Patent Application Laid-Open No. 57-59457, a rotor core is provided corresponding to each stator, the rotor core is fixed to a single axis, each rotor is provided with a high resistance starting winding, and two
A low-resistance secondary conductor is provided in each rotor core to guide the operating winding, and when starting the motor, the electromagnetic phase input to one stator winding is changed to 1 by switching the electromagnetic switch.
It switches from 80 degrees to 120 degrees to 0 degrees and enters normal operation. During this switching operation, the heat generated in the starting winding is quite large and requires electrical insulation from the secondary conductor, so the conductivity of the heat decreases and most of the generated heat is absorbed by the iron core. Otherwise, it is conducted to the end of the short-circuit ring and dissipated, causing a decrease in the leakage reactance of the secondary conductor, so considerable consideration had to be taken for heat dissipation and insulation of the starting winding. Also, this one also
It is not possible to arbitrarily change the speed in the low speed region, and if the rotation speed is set to match the phase of one stator to 150 degrees or 120 degrees by operating the electromagnetic switch,
The heat generated by the starting winding is extremely high, and this heat generation causes a drop in efficiency and durability due to current loss in the winding and conductor. There was a problem that it could not be used as a practical electric motor that could control speed changes.

Furthermore, the variable speed induction motor disclosed in Japanese Patent Publication No. 27-4357 connects rotor conductors divided into 20%,
A structure in which windings each having a fixed stator and a movable stator are connected to a power source in parallel, a rotating device is connected to the rotating stator, and an indicator light is provided to display the rotation speed. It is. This device is disclosed in the above-mentioned JP-A-54-29005 and JP-A-57-594 in that the speed can be changed freely.
It is different from that in Publication No. 57.

However, this also does not connect the rotor conductor with a short-circuited resistive material between the two sets of rotors, and cannot control the rotational speed range to low to medium speeds to generate sufficient functionality. Particularly in applications that require reduced torque characteristics such as fans and pumps, the resistance material is not short-circuited, so the torque cannot be regulated to the variable speed required for the drive source. For electric motors,
The problem is that the rotational speed is simply notified by increasing or decreasing the indicator light that indicates the rotational speed, and the rotational speed cannot be automatically controlled based on the degree of increase or decrease in the indicator light.

[Purpose of the invention]

One of the objects of the present invention is to provide fans, pumps, etc.
These drives can be controlled steplessly to increase or decrease, and the torque characteristics of electric motors that are frequently started and stopped can be improved.
The aim is to construct an electric motor free from harmonic interference.

Another objective is to be able to control the rotational speed of the electric motor to any speed from low speed to high speed, and to configure the speed control at a low cost. The goal is to install equipment that facilitates the process.

Another objective is to install an insulating material on the conductor insertion hole provided in the rotor core, the conductor, or both, to reduce the leakage reactance of the electromotive force leaking from the conductor to the rotor core. The purpose of the present invention is to provide a technology that effectively increases the current flowing through the resistance material connected to the short circuit between multiple rotor cores, and improves the torque characteristics and efficiency during starting and arbitrary speed rotation. .

In the present invention, the term "insulating material is attached to the conductor insertion hole and the conductor" is used, but "insulating material" is not limited to attaching an insulating material to the conductor insertion hole or the conductor. It is a general term that includes the conductor insertion hole of the rotor core or the surface layer of the conductor that has been subjected to various insulation treatments.

As for the rotor configuration of the variable speed induction motor of the present invention, conductors can be inserted into any of the rotor configurations such as a normal squirrel cage type, a double squirrel cage type, a deep groove cage type, and a special squirrel cage single winding type. Applicability or formation into a single-phase or three-phase motor can be arbitrarily selected and adopted.

(Means for Solving the Problems) -10= In order to achieve the above technical problem, the present invention provides a plurality of The plurality of conductors are connected to each other to form an integral rotor, and the plurality of conductors are short-circuited by a resistive material between the plurality of rotor cores, and the plurality of conductors are connected concentrically with the plurality of rotor cores. and a plurality of stators are arranged in parallel and opposite each other on the outer periphery of the machine frame, and at least one stator among the plurality of stators installed on the inner periphery of the machine frame is a rotatable rotary stator. In the electric motor formed into a voltage phase device, each of the windings wound around the plurality of stators is connected in parallel to a power source, and the rotary stator can be freely rotated and fixed. In addition, a speed detector mounted directly or indirectly on the rotor and the drive device are connected via a control device, thereby providing a means to solve the problem.

Further, in another aspect of the invention, a rotation position detector for detecting the rotation position of a rotation stator rotated by the operation of a drive device connected to a control device is installed directly or directly in relation to the rotation stator. A measure was taken to indirectly monitor the situation and communicate the rotational position detector to the control device.

In another invention, a control device is equipped with a phase difference setting device that can change the phase difference of voltages induced from each of a plurality of stators within an arbitrary range of 0° to 180°, and the control device A method was taken in which the drive device was connected to the drive device.

It was used as a means to

Roughly, as another configuration of the present invention, an insulating material is attached to a conductor insertion hole drilled in the rotor core into which the plurality of conductors are inserted, one or both of the plurality of conductors, It was used as a means to solve problems.

[For production]

When the rotating stator, which constitutes a voltage phase shifter, is rotated in relation to at least one stator of the plurality of stators, a plurality of conductors wound around one rotor core are connected to each other. A phase shift occurs in the phase of the voltage induced between the rotor conductors, and the degree of phase shift is controlled by increasing or decreasing the combined voltage induced in the rotor conductors by operating a voltage phase shifter. Then, the rotation speed of the rotor can be changed arbitrarily.

By the way, the windings wound around each of the plurality of stators are connected in parallel to a power source, and the plurality of conductors are connected through resistive materials between the plurality of rotor cores equipped with the plurality of conductors. Due to the short-circuited configuration, the current flowing through the resistor material is approximately equal to (1/2) x (differential voltage induced in the rotor conductor from both the rotating stator and the stator) ÷ the resistance value of the resistor material). A proportional current flows, and a current approximately proportional to (the sum of the voltages induced in the rotor conductor from both the rotating stator and the stator)/(impedance of the rotor conductor) flows in a superimposed manner.

As a result, the slip and torque characteristics become a mixture of the characteristics when a secondary resistance is inserted in a general wound induction motor and the characteristics when the primary voltage of a general induction motor is controlled.

Even if the drive source, such as a fan or pump, has a reduced torque characteristic as a load and frequently repeats start/stop and speed change control, if the speed control is input to the control device, the control device can The drive device is actuated by the output signal of the voltage phase device and the rotation stator is rotated, and the detection signals of the rotation position detector and speed detector are communicated to the control device and input into the control device. Since the drive device automatically stops when the speed control value is reached by the output signal from the control device, there is no need for cumbersome manual operations, and this also simplifies the speed change control device and makes the device less expensive. , it has the characteristic that it does not cause problems that induce harmonic interference.

In addition, since the conductor insertion hole is drilled in the rotor core or the conductor is covered with insulating material, even if the current flowing through the rotor conductor becomes large, especially during startup or low rotational speed operation, the conductor will not rotate. Leakage reactance of electromotive force leaking into the core does not occur, and the current flowing from the conductors on one side and the other side effectively flows through the resistance material and circulates, preventing leakage reactance of the conductors and improving torque characteristics and efficiency. It will improve.

〔Example〕

Examples will be described with reference to the drawings. Reference numeral 1 shown in FIG. 1 is a variable speed induction motor according to the present invention, and the induction motor 1 has the following configuration. Rotor cores 2 and 3 made of iron cores are mounted on the rotor N4 with an arbitrary interval between them, and a non-magnetic core 9 is interposed between the rotor cores 2 and 3.

The non-magnetic core 9 formed between the rotor cores 2 and 3 is made of asbestos, ceramic material (pottery, etc.) with high heat resistance.

Synthetic resins (including non-magnetic new ceramics, etc.) (mica,
Silicone resin synthesized by mixing a few percent of asbestos, glass fiber, etc.
Silicone resin, fluororesin, etc.) aluminum material, stainless steel is used, and openings are provided at appropriate locations in the non-magnetic core 9.
Sometimes.

A plurality of conductors 5 and 5 are inserted in communication with the rotor cores 2 and 3.
. . . to form an integral rotor 8 (details of which will be discussed later), and both ends of the plurality of conductors 5 . . . are connected by short-circuit rings 6 and 7.

In addition, the rotor 8 is attached to the rotor cores 2 and 3 and the non-magnetic core 9.
A plurality of ventilation ll1i1 connected to both sides 10.11 of
2... is established. A plurality of conductors 5 and 5 installed on the rotor 8
... is a nichrome wire or carbon-containing steel that serves as a connecting material for each of the plurality of conductors 5 in the non-magnetic core 9 portion between the rotor cores 2 and 3.

They are short-circuited and connected via a resistive material r such as a conductive ceramic. A plurality of cooling bodies 13 made of a material with a high heat dissipation effect are attached to the inner end surface of the non-magnetic core 92 rotor core 2°3, and the cooling bodies 13 are attached to the cooling blade vehicle body 13A.
It is formed.

The cooling member 13 may be formed into a cooling fan using a non-magnetic material in the non-magnetic core 9, or may be formed into various shapes and mounted on both sides of the rotors 2 and 3. The cooling body 13 shall be insulated. In some cases, the cooling body is attached to the rotor shaft 4, and the cooling body 13 may be formed with a plurality of resistive materials r, for example, in a zigzag shape or any other desired cooling stirring body. . Bearing discs 15 and 16 provided on both sides of the cylindrical machine frame 14 are connected to connecting rods 17 with bolts at both ends...
The rotor 8 is integrally assembled with the and nut 18...
Cooling impellers 19 and 20 are installed on both sides of the rotor shaft 4.
Bearing 21.21 with both ends fitted in bearing disc 15.16
The rotor 4 is rotatably supported.

As shown in FIGS. 1 and 2, a rotary stator 31 and a second stator 25, each having a winding 22 and 23 concentrically arranged on the outside of the rotor cores 2 and 3, are arranged in parallel. set, machine frame 14
A stop ring 28 is provided with a sliding bearing 26 between the rotating stator 31 and the rotating stator 31, and the sliding bearing 26 is fitted into the machine frame 14.
The machine frame 14 and the second stator 25 are fixed by a ventilation fixing ring 27 with ventilation windows in several places.
A and a fixing ring 27B. Rotating stator 31
A gear 33 is fitted on the outer peripheral surface of one side, and the machine frame 14
A driving gear 36 is pivotally attached to a small motor 35 for forward and reverse rotation, which is formed by a drive device 29 fixedly installed on the outer periphery of the machine frame 14. 17= A plurality of ventilation holes 4o... are bored in the board 15, 16.

Further, as shown in FIG. 3, each of the rotary stator 31 and the second stator 25 is star-connected and provided with windings 22 and 23 (delta connection may also be used, and pole-converting windings are provided). ), each winding 22, 23 is connected in parallel to the power supply.

Ventilation is provided in a space 66 formed between the rotor cores 2 and 3, the rotary stator 31 mounted on the sliding bearing 26, and the second stator 251 fixed to the ventilation fixing ring 27A and the fixing ring 27B. WA67, a plurality of openings are opened in the machine frame 1 to communicate with the ventilation trunk 67, and the plurality of openings are formed into an arbitrary number of ventilation ports 68 and ventilation ports 69. A motor 72 that is pivoted to a wind turbine 71 is connected to a blower body 70.
The motor 72 is formed to be able to freely rotate in forward and reverse directions, and is connected to arbitrary speed change means such as a voltage regulator and an inverter, and is equipped with an indicator, a display, and a display.
A control mechanism 65 equipped with a switch is connected, and a temperature detector 64 mounted on the ventilation barrel 67 and the control mechanism 65 are connected. The blower device 73 is fixed to the machine frame 14, and the air suction portion 74A of the blower device 73 is connected to the air exhaust port 69 to connect the ventilation barrel 6.
A ventilation port 68 for introducing outside air from the other side of the ventilation port 69 is connected to the ventilation barrel 67, and a ventilation portion 74B is formed in the ventilation barrel 70. Further, a cooler, a condenser, a refrigerant gas, and various refrigerant devices thereof may be connected to the air outlet 69 directly or through a pipe.

A drive gear 36 partially inserted into the machine frame 14 from the frontage part 37 is engaged with a gear 33 fitted to the rotary stator 31, and a small motor 35 equipped with a switch forming the drive device 29 is connected. A second fixing member is connected to the rotary stator 31 via a rotary mechanism 30 consisting of a gear 3'3 and a drive gear 36, so that the rotary stator 31 can freely rotate, and is fixed to the machine frame 14. A rotary stator 31 that is rotatable in relation to the child 25 is formed in the voltage phase shifter 103 .
In addition to the above-mentioned embodiments, various methods that achieve this object can be selected and adopted.

A magnetic sensor 9--32 is mounted on the outer circumferential surface of the rotary stator 31, and a plurality of magnetic detecting bodies 34 having different terminal diameters for detecting magnetism are connected to a non-magnetic plate in relation to the magnetic sensor 32. 41
, and a non-magnetic plate 41 is attached to the inner peripheral surface of the machine frame 14.
The magnetic sensor Fj-32 and the magnetic sensing body 34 form a rotational position detector 42, and the magnetic sensor 32
is electrically connected to a display 43 into which the rotational position of the rotational stator 31 set for each magnetic sensing body 34 is input. Reference numeral 38 denotes a solenoid for controlling the entry and exit of a protruding piece.The solenoid 38 is attached to the machine frame 14, and its protruding piece is freely engaged with a gear 33 fitted to a rotary stator 31. A speed detector 44 such as a tacho generator is mounted on the shaft 4, and the speed detector 44 is connected to a speed indicator 45. Note that the speed detector 44 is not limited to being mounted on the rotor shaft 4, and may be mounted on the rotor cores 2, 3, non-magnetic tachometers, etc., such as a strobe type tachometer or a photoelectric tachometer. It may be used in conjunction with the body core 9, conductor 5, etc.

Next, the rotor core 2.3 shown in FIG. 4 will be explained.

The rotor 2,
3 and non-magnetic material] A9 is inserted and placed on top. To explain the rotor cores 2 and 3 in more detail, the rotor cores 2 and 3 are formed into an integral rotor 8 by polymerizing and connecting a plurality of silicon steel plates 77, both sides of which are treated with a phosphoric acid coating. Ru.

The silicon steel plate 77... has a plurality of conductor insertion holes 78..., and the shorting ring 6 is inserted into the center shaft 75 at the lowest stage, and the silicon steel plate 77... has a predetermined thickness. is polymerized and superimposed.

Seven insulating tubes of the same length are inserted into the conductor insertion holes 78 of the rotor cores 2 and 3 made of silicon steel plates overlapped to a predetermined width.

The insulating tube 79 is formed into a thin tube using a synthetic resin (silicon resin, silicone resin, fluororesin, etc.) mixed with a few percent of particulate matter such as mica, asbestos, or glass fiber, and is made of a thin tube containing a plurality of conductors 5. . . . A resistance material r .
a, and the plurality of conductors 5 protruding from the non-magnetic core 9a are inserted into the inner peripheral surface of the insulating tube 79 inserted into the conductor insertion hole 78 of the rotor core 2. . Next, contrary to the above, the non-magnetic core 9b is inserted on the opposite side of the plurality of conductors 5... to which the resistive material r... is welded, and the conductors 5 and 5 protruding from the non-magnetic core 9b are inserted. An insulating tube 79 is inserted into each of the conductors 5, and the silicon steel plate 77 of a predetermined width is connected to the rotor core 3 and the short-circuit ring 7 through the seven insulating tubes.・Insert into. The insulating tubes 79... may be glued to the conductor insertion holes 78..., and the short circuit rings 6, 7, the rotor core 2゜3, the conductor 5..., the non-magnetic cores 9a, 9b. After inserting each of the conductors in turn, fixing the shorting ring 6 and rotating the other shorting ring 7 to skew the plurality of conductors, both ends of each conductor 5 are struck with a helter. However, when the short circuit rings 6, 7 and the conductors 5 are completely tightened, the rotor cores 2, 3 and the non-magnetic core 9 are formed into an integral rotor 8. Note that each of the above-mentioned work steps is mainly performed by automatic loading. In addition, an insulating resin paint is applied to the conductor 5 inserted into the inner peripheral surface of the insulating tube 79 inserted into the rotor core 2゜3.
When the conductor 5... is skewed, the insulation tube 79...
Even if the film is thin, there is no need to worry about poor insulation between the conductor insertion holes 78 and the conductors 5. In addition, in electric motors that have a small starting torque and are used only in high-speed rotation areas, the insulating tube 79
In some cases, the conductor 5 is used by simply applying an insulating resin paint without using the insulating resin paint, but the surface of the conductor 5 coated with the insulating resin paint is left to dry naturally. Baking and drying is preferable from the standpoint of insulation and durability.

The effects of the above configuration will be explained below.

When the windings 22.23 are energized from a commercial three-phase power source, a rotating magnetic field is generated in the rotating stator 31.25, voltage is induced in the rotor 8, and current flows through the conductors 5 of the rotor 8. The rotor 8 rotates. The second stator 25 with respect to the rotating stator 31
When the amount of each rotation is set to zero, there is no phase shift in the magnetic flux of the rotating magnetic field generated in each stator 31.25, and the details will be explained later when the resistance material r.
Since no current flows through the motor, it has the same torque characteristics as a general induction motor.

Next, a case will be described in which the small motor 35 is operated to rotate the rotary stator 31, and the rotary stator 31 is rotated by θ E with an electrical phase angle. Rotating stator 31 and second stator 2
The magnetic flux φ1 of the rotating magnetic field created by 5. The phase of φ2 is shifted by θ, so the voltage L induced in the conductor 5 of the rotor 8 by the rotating stator 31 and the second stator 25 is 3+
, tA2 are shifted in phase by θ. Now, the second stator 2
Voltage d induced in conductor 5 of rotor 8 by 5
2 as a reference, and the voltage is 62=SE. Here, S is slip and E is the induced voltage when slip is 1. At this time, the voltage white 1 induced in the conductor 5A by the first stator 24 becomes 6+=3EεjO.

(Induced voltage when E-slip 1) What is shown in Fig. 5 is the case where the resistive material r... that short-circuits the plurality of conductors 5... is not installed in the non-magnetic core 9 section. This shows the relationship between the slippage S of the rotor 8 and the active power P of the rotor input. When the voltage phase is θ-〇°, the active power P is maximum, and when the voltage phase is 0° and θ<180°, It becomes something smaller than that. Here, if the resistance and inductance of the conductor 5 are R and the angular frequency of the power source is ω, then the maximum active power P is 5−(R/ω
L) Appears when .

Since the active power P is proportional to the driving torque of the induction motor 1, the voltage induced in the rotor 8 is adjusted by operating the small motor 35 and rotating the rotary stator 31 relative to the second stator 25. However, the speed of the rotor can be controlled steplessly.

Next, the respective resistances from the short-circuit rings 6 and 7 of the conductors 5 of the rotor 8 to the connecting members are set to R1 and R2, and the inductance is set to 11. L2, the angular frequency of the power source is ω, and the resistance of the resistive material that short-circuits each conductor 5 is r, the electrical equivalent circuit of the rotor 8 is as shown in Fig. 6, and the symbol is I+, I2. I3 indicates the current flowing through each branch.

Next, when converting the circuit shown in FIG. 7 into an equivalent circuit viewed from both stators 31 and 25 side, it becomes as shown in FIG. 6, and RI=R
2, When LI=L2 and θ-0°, 13=II-I2
= O, and no current flows through the resistor material r.

This means that when θ-0°, the torque T is equal to the value without r. Therefore, when θ=0°, it has the same torque characteristics as a conventional induction motor.

Next, RI=R2, L+=L2rθ-18o.

Next, I+=-I? , l3=TI-I2=21+
Therefore, in a conventional induction motor, if the resistance of the rotor conductor is set as Ri'=R2=R, the result is similar to that in which R increases to R+2r.

As the rotor 8 rotates, outside air is sucked into the machine frame 14 by the cooling impellers 19 and 20 through the communication ports 40 bored in the bearing discs 15 and 16, and the cooling impellers 19 wind the windings. 2
22 rotor core2. The conductor 5... etc. are cooled and the exhaust hole 3
9A... to the outside of the machine frame 14, and the cooling impeller 2
0, the surplus air sucked by the impeller 19 flows into the ventilation barrel 12 . winding 23. The second stator 25 is ventilated and cooled, and the exhaust air is discharged from the ventilation holes 39B of the machine frame 14 through the ventilation window of the ventilation fixed link 27A, and the windings 22, 23, the rotor core 2 , 3. Non-magnetic material 9.
A function is stably exerted on each of the conductors 5...

The speed of the rotor 8 is arbitrarily changed by controlling the phase shift using the rotary stator 31 and increasing or decreasing the current flowing through the conductors 5 of the rotor 8. be able to.

When each of the windings 22 and 23 of the rotary stator 31 and the second stator 25 are connected in parallel to a commercial three-phase power supply, the input to the windings 22 and 23 of the rotary stator 31 and the second stator 25 is The voltages are the same, and the voltages induced from each of the stators 31.2'5 to the conductors 5... of the rotor 8 are the same, but the phases of the voltages differ by Pθ, and the voltages induced on the conductors 5... of the rotor 8 are the same. The current flowing through the resistive material r... which serves as a connecting material between the
2) The current is approximately proportional to x (differential voltage induced in the rotor conductor from each of the first and second stators)÷(resistance value of the resistance material r...). However, in the conductor 5 of the rotor 8, in addition to the current flowing through the resistor material r... The currents flow in a superimposed manner. (The above sum voltage is maximum when Pθ-π is zero and Pθ=0, and the impedance of the rotor conductor is composed of the resistance of the conductor and the secondary leakage reactance, respectively, so it varies depending on the slippage.) Therefore, the conductor of the rotor 8 The ratio of the current flowing between the plurality of conductors 5 through the resistive material r to the magnitude of the current flowing through the conductors 5 varies depending on the slip and resistance value even if Pθ is constant. The slip and torque characteristics when Pθ is constant are the characteristics when the secondary insertion resistance of a general wound induction motor is constant, and the characteristics when the primary voltage of a general induction motor is controlled. As shown in Fig. 9, this characteristic is a mixture of the two stators 3i'' and 25 windings 22 and 23, and this characteristic has a wider speed control range than the characteristic when both stators 3i'' and 25 windings 22 and 23 are connected in series. It will become narrower. However, the present invention exhibits excellent torque characteristics when used as a drive source with reduced torque characteristics as a load, such as a fan or pump, and as an electric motor that frequently repeats start/stop and speed change control. 9 shows a constant torque characteristic, whereas FIG. 9 shows a reduced torque characteristic. □Next, the leakage tank 29 of the current flowing through the rotor conductor will be explained with reference to FIGS. 4 and 10.

The current flowing in the conductor (electromotive force) is expressed as e=vBJJ (B...magnetic flux density, Q...length, ■...speed).

If the insulation between the conductor and the silicon steel plates 77a to 77f is perfect at points A to F of the conductor 5, the sum of the electromotive force e flowing in the conductor is as follows: This is the line indicated by P. The magnitude of the electromotive force P at the conductor 5 (7JA point to F point is determined by the magnitude of the resistive material r',
The electromotive force P increases in proportion to the direction from the entry point of the conductor 5' to the point F. If this is not done, the larger the resistance material r is, the greater the electromotive force P will be, and the potential will leak from point F of the conductor 5 to one point of the silicon steel plate 77, and from point F of the conductor 5 to the resistance material r. The flowing electromotive force P decreases, and the rotational torque of the rotor decreases significantly, resulting in a corresponding decrease in efficiency.

However, in the present invention, since one or both of the conductor insertion holes 78 of the silicon steel plates 77 and the conductors 5 are insulated, even if the resistor is formed to a large extent, There is no leakage from the conductors 5 to the silicon steel plates 77, which has a great effect of improving torque characteristics and efficiency.

By the way, when the variable speed induction motor 1 starts operating (see FIG. 2), if the rotational position of the rotary stator 31 detected by the magnetic sensor 32 is, for example, 60 degrees in electrical angle,
If the power is turned on without considering the starting characteristics of the load connected to the rotor shaft 4, the electric motor 1 may not be able to start or may not start properly if a load that requires a large starting torque is connected. Conventionally, securing sufficient capacity for equipment was a problem, but the features of the present invention are that the starting equipment is downsized, and it has a configuration that allows smooth starting and variable speed. Before starting the operation of the electric motor 1, the magnetic sensor 32 of the rotation position detector 32 detects where the rotation fixed position of the rotation stator 31 is. For example, the rotational position of the rotational stator 31 can be detected by the magnetic detection body 34G.
The magnetic sensor 32 detects and informs the display 43,
According to the signal value on the display 43, the rotary stator 31
Digitally displays the rotational position of 60 degrees in electrical angle. Based on the display of the rotational position, the solenoid 38
Activate to unlock gear A7-33, and
The switch reverses the small motor 35 and the rotor 1
For example, when the rotational position of the rotating stator 31 is set to 150 degrees in electrical angle so that the starting speed corresponds to the starting characteristics of the load connected to the ThI 14, the magnetic sensor 32 detects the magnetic sensing body 34f. The rotating stator 3 is displayed on the display 43.
The motor is operated until the target starting rotational position of 150° is displayed, and when the target starting rotational position is displayed, the operation of the small motor 35 is stopped and the solenoid 38 is activated to lock the gear 33. , fixes the rotation of the rotation stator 31.

After the above operation is completed, when the windings 22 and 23 are energized from the power supply, the rotor shaft 4 starts the rotary stator 31 at a smooth rotational speed corresponding to the starting rotation position, and then the solenoid 3
8 to unlock the gear 33, operate the switch to rotate the small motor 35 in the forward direction, detect changes in the rotational speed of the rotor shaft 4 with the speed detector 44, and detect the change in the rotation speed of the rotor shaft 4. When the speed indicator 45 detects that the rotational speed has reached the desired rotational speed, the small motor 35 is stopped and the solenoid 38 is activated to lock the gear 33 and fix the rotation of the rotary stator 31.

Note that the rotational position of the rotational stator 31 at the time of startup is set to an arbitrary rotational position corresponding to the startup characteristics of various loads connected to the rotor shaft 4, and the magnetic It goes without saying that mounting any number of sensors 32 may be selected as appropriate.

Furthermore, the rotational position detector is not limited to the above embodiments, but may include a limit switch.

It can be implemented by forming a plurality of photosensors, etc., or by selecting a rotary encoder with a control function, or various types of rotational position detectors.

After the adjustment of the target rotation position is completed, the motor 72 of the blower device 73 is activated to rotate the windmill 71 at the same time as the start switch is input.
8 to the ventilation shell 67, and the outside air is passed to the cooling body 13.
The inside of the ventilation shell 67 is stirred to cool and radiate heat from the non-magnetic core 9 or the conductor 5..., the resistance material "..., etc., and
The air inside the air blower 70 is sucked into the air blower body 70 through the air outlet 69 and is exhausted to the outside of the air blower 11!70 through the air outlet portion 74B.

In the case of operation in a high speed region, the air blowing action of the cooling impeller 19, 2'0 that sucks outside air is distributed to the ventilation barrel 12... 9 is cooled, exerts a heat dissipation effect on the conductor 5..., the resistor material r..., and the exhaust air is discharged to the air exhaust cylinder 39A...

Since it is discharged from each of 39B..., the resistance material r.
The heat generated by ... does not become very high and no heat is stored. However, in the low-to-medium speed rotation range when the speed is changed, the heat generation of the resistance material r... increases rapidly, so the air blowing action of the cooling impeller 1.9.20 alone causes the resistance material r...
・Although the function of radiating heat from
3, the resistance material r... is cooled and heat radiated regardless of the change in the rotational speed of the electric motor 1, and the electric rotation efficiency is effectively exerted, and the heat generation of the resistance material r... The durability of each of the nonmagnetic cores 9 involved in heat generation can be improved and maintained.

Note that the air exhaust port 74B of the air blower 73 is communicated with an arbitrary number of air outlets 68 provided in the machine frame 14, so that outside air is introduced into the ventilation shell 67 by the air blown by the air blower 73, and the exhaust air is passed through the arbitrary number of air outlets 68. 69 may be excluded. In any case, since the outside air is introduced into the ventilation shell 73 from one side of the machine frame 14 and the exhaust air is exhausted from the other side of the machine frame 14, the resistance material r... and the non-magnetic core 9 are cooled. The air outlet 68. can have an effective effect on heat radiation. Exhaust port 69
may be plural.

Moreover, if cooling air is introduced into the ventilation cylinder 67 from the ventilation port 68 by an arbitrary refrigerant device and the air in the ventilation cylinder 67 is cooled, the non-magnetic core 9. Cooling and heat dissipation to the resistance material r... is made more effective. The blower device 73 is operated by the motor 72 as the rotor shaft 4 changes speed from high speed rotation to low speed rotation.
The rotational speed of the M feeding device 73. may be controlled toward high speed rotation. During high-speed operation of the electric EL11, the refrigerant device controls the motor 72 or any of the refrigerant devices as appropriate, and prioritizes energy saving while checking the relationship with the electric efficiency of the electric motor 1 based on data. It may be avoided. Then, based on the signal obtained by the temperature detector 64, the motor 72 can be automatically operated according to an operation signal set in the control mechanism 65. In addition,
The blower device 73 may be arbitrarily selected and implemented by disposing it elsewhere and communicating with the blower port 68 or the blower outlet 69 via a duct, without directly connecting it to the machine frame 14.

What is shown in FIG. 11 is the silicon steel plate 7 of the rotor cores 2 and 3.
7... are overlapped and connected, and a plurality of conductor insertion holes 78...
This figure shows an example in which an insulating paint is applied to each of the parts.

The rotor cores 2 and 3 are insulated, for example, by the following method. A rotor core mounting board 81 is rotatably mounted on the workbench 80, a central shaft 82 is fixedly mounted on the rotor core mounting board 81, and the rotor core mounting board 81''
A paint spraying device 85 is connected to a servo motor 83 that controls the rotation of the paint tank 8 and is mounted on a support 84 erected on a workbench 80 so as to be able to move up and down.
The paint tank 8'6 is equipped with a heater 88 and a spray controller 89.6 with an air compression valve. A stirring device 90 equipped with a motor and a motor 91 for controlling vertical movement are installed, and a flexible spray pipe 92 with elasticity is provided extending from the bottom of the paint tank. This is a massing machine that prevents adhesion to the surface of silicon steel plates.

In the above-described apparatus, the paint tank 86 is filled with an arbitrary insulating paint, and the heater 88. Warm the paint with a stirring wave @90 and stir it so that there are no spots. Next, the servo motor 83. is activated by a signal set in the control device. The motor 91 is activated to rotate the rotor core mounting plate and stop it at a predetermined position, and at the same time, the paint spraying device 85 is lowered and the spray pipe 92 is inserted to the lower part of the conductor insertion hole 78 of the rotor cores 2 and 3. Then, while applying paint to the inner peripheral surface of the conductor insertion hole 78 by operating the spray controller 90, the motor 9
1, the paint spraying device 85 moves upward, and when the application to the conductor insertion hole 78 of the uppermost silicon steel plate 77 is completed, the spraying from the spraying controller 90 is stopped, and the lower end of the spraying pipe 92 is connected to the mask board. When a small amount of water flows out from 93, the motor 91 stops, and the above-described operation continues thereafter.

Since the skew of the conductor insertion hole 78 due to the plurality of silicon steel plates 77 is done in advance by a skew control device, the conductor is inserted into the conductor insertion hole 78 after applying an insulating paint. However, there will be no insulation failure, and it is effective if a high temperature baking drying process is performed after applying the paint. We can also plasma spray any insulating powder material.

The use of thermal spraying means to form an insulating material can be arbitrarily selected and carried out as required.

The effect of preventing the leakage reactance of the conductor 5 by applying the insulating paint to the conductor insertion hole 78 is similar to the effect described in connection with Fig. 10 above, so the details will be explained below. will be omitted.

In addition to the embodiments described above, the conductor insertion hole 78 of the rotating core 2.3
... or the surface layer of the conductor 5...
Also, 1c may be formed into an insulating material by applying an insulating anodic oxide coating to both sides, and if the conductor 5 is made of aluminum, an alumite coating can be applied to prevent deterioration of durability due to oxidation. can be prevented. Then, if a Teflon (registered trademark) coating is applied to the surface of the conductor insertion hole 78, conductor 5, etc., which has been subjected to an anodized coating treatment, or after coating with any of the synthetic resin paints described above, an insulation effect can be achieved. Durability can be improved accordingly.

Furthermore, in addition to the above-mentioned embodiments, conductors 5 and
For example, use aluminum material, and short-circuit the resistance material 6, 7.
In many cases, they are integrally cast together with the cooling impellers 19 and 20, but in this case, as described above, the insulating tube 79 or insulating paint is applied to the conductor insertion holes 78 of the rotor cores 2 and 3. If the casting process is performed after mounting on the conductor, a stable and constant dimension can be ensured between the cast conductor and the conductor insertion hole 78, so that the cast conductor does not cause insulation defects.

Moreover, instead of integrally casting as described above, for example, the conductors 5 are inserted into the conductor insertion holes 78 of the rotor core 2.3, and the conductors are inserted into the conductor insertion holes 78. Even when filling and injecting the synthetic resin described above into the space of the conductor 5..., when filling and injecting the synthetic resin, the conductor 5...
· may be pressed in one direction of the conductor insertion holes 78, resulting in -C insulation failure. or apply insulating paint to the conductor insertion hole 7.
If synthetic resin is filled and injected after inserting the conductor 5 into the conductor insertion hole 78, the insulation effect between the conductor insertion hole 78 and the conductor 5 will be strong, and the conductor 5 will be Leakage reactance is not affected at all, and oxidation due to ventilation is also prevented, resulting in significant effects such as improved durability.

And, it is not something that continues to run and stop frequently,
In the electric motor of the present invention whose speed change control region is a medium-speed and high-speed rotation region, but whose torque characteristics are mainly controlled, the rotor core 2 is
, 3 conductor insertion hole 78... (silicon steel plate 77...), or apply an insulating paint to one or each of the conductors, or conductor 5 protruding from the non-magnetic cores 9a, 9b. Filling and injecting various insulating synthetic resins of arbitrary thickness into a ring shape, or non-magnetic material 9a,
The conductor 5 can be inserted into the inner peripheral surface = 41- of both ends of the 9b, and the conductor insertion hole 7 can be inserted into the outer peripheral surface.
If it is formed into various shapes such as one that can be inserted into the
. . may be formed of a low-resistance material, the sum P of the electromotive force of the conductor 5 does not generate the large electromotive force required in the low rotation region.
There is no need to apply insulation material over the entire length of...

What is shown in FIG. 12 shows that each of the plurality of conductors 5 installed in each of the rotor cores 2 and 3 is connected to the rotor in the space between the rotor cores 2 and 3 or in the non-magnetic core part. A high-resistance ring 94 that is inserted into the shaft 4 is used as a connecting member.
This is an example of short-circuiting due to... Even if the resistive material r is not connected to all the conductors 5, it can obtain the appropriate effect.

Next, one embodiment of automatic control of a variable speed induction motor will be explained with reference to the block diagram shown in FIG.

(See FIGS. 1 and 2) Input/output control circuit 96, control circuit 97. Arithmetic circuit 98. A speed detector 44 such as a tachometer generator equipped with a speed indicator 45 mounted on the rotor shaft 4 and a voltage for detecting the rotational position of the rotation stator 31 are connected to the input side of the control device 95 consisting of a memory circuit 99 and the like. Phase difference detector 4
2, a temperature detector 64 attached to the appropriate position of the ventilation trunk 67,
A keyboard 101 equipped with an activation switch 100 and a display is connected to a voltage phase difference setting device 102, and a small motor 35 (voltage phase difference setting device 102) is connected to the output side of the control device.
3) are connected to the motor 72 of the blower device 73 for cooling and dissipating heat from the conductors 5 . . . , the resistive material r . . . , and the solenoid 38 . The following control values are input from the keyboard 101 to the storage circuit 99 of the control device 95. That is, the voltage phase difference detector 42 detects the rotational position of the rotational stator 31 corresponding to a phase angle of 0° to 180°.
The set values of the starting phase difference and the running phase difference are set to Several types of starting phase difference settings that match the starting characteristics,
A reference temperature setting value for controlling the motor 72 to increase or decrease with respect to the temperature detected by the temperature detector 64 is input.

When the operation preparation key is input from the keyboard 101 at the start of operation, the voltage phase difference detector 42 detects the current rotational position of the rotational stator 31 and displays it on the display.
When an arbitrary starting phase difference set value that matches the starting characteristics of the load connected to the rotor shaft 4 is input from the voltage phase difference setting device 102, the solenoid 38 is activated in response to a signal output from the memory circuit 99 of the control device 95. It operates to unlock the gear 33 fitted to the rotary stator 31, and also activates the small motor 35 to rotate the rotary stator 31. When the phase difference detector 42 detects this, the small motor 35 automatically stops.

When readiness for operation is displayed on the display, a phase difference setting value for arbitrary operation is input to the control device 95 from the voltage phase difference setting device 102 according to the starting torque of the load connected to the rotor shaft 4, and the operation position is set. The rotation speed of the small motor 35 is calculated to obtain the phase difference set value. When the starting switch 100' is activated and an input signal is sent to the control device 9'5, the small motor 35 is operated in response to the output signal of the control device 95 to rotate the rotary stator 31, and the input signal is transmitted to the control device 9'5. When the voltage phase difference detector 42 detects the operating phase difference set value, the small motor 35 is stopped.

Then, the speed value obtained by communicating the detected value of the speed accumulator 44 attached to the rotor shaft 4 is compared with the speed control value set in the control device 95, and if there is a difference in speed, , the control device 75 outputs an output to the small motor 35 to correct and control the rotational speed, and operates the rotary rotor 38 to lock the gear 33 of the rotary stator.

Corresponding to the phase difference setting value for starting or the phase difference setting value for operation set in the voltage phase difference setting device 105, the output signal from the control device 5 sets the rotational speed of the J motor 72 to a high side or a low side. controlled by the side.

When the temperature detection value of the temperature detector 64 communicated to the control device 5 becomes higher than the reference setting value set in the memory circuit 99, the rotation speed of the motor 72 is corrected by a signal output from the control device 95. Then, the ventilation effect in the ventilation barrel 67 is increased to restore the normal function of cooling and dissipating heat from the non-permeable cores 9 . . . , the resistive material r . . . . Furthermore, regardless of the phase difference control of the voltage phase difference setter 102, the temperature detector 6
The control device 9 controls the detection value of 4 to become the reference temperature set value.
The output signal from motor 72.5 of blower device 73 is activated.
No: The rotation speed may be controlled by increasing or decreasing, or by turning it ON or OFF.

And, the stator has a configuration in which pole number conversion winding is applied (
In this case, the rotary core shall be wound with a winding wire)
In this case, if the output side of the control device 95 is connected to a switching switch, it is possible to automatically perform a wide range of gear changes in response to the load reduction torque. In addition, a connection switch is provided to switch the connection of the windings wound around each of the rotary stator and the stator to either delta connection or star connection, and the output signal of the control device 95 determines whether the connection is between delta connection and star connection.
Alternatively, if configured to automatically switch to star connection, the gear shifting range can be expanded.

Furthermore, the multiple stator induction motor of the present application can also be used as an induction generator, and the rotor shaft 4 has a turbine and a gas turbine.

If a solar thermal power generator or the like is directly connected to generate electricity, an expensive governor can be omitted. In addition, when an internal combustion engine is connected as a prime mover, it can correspond to the rotational speed of the internal combustion engine for minimum fuel consumption, and even when the power source of energy is weak and unstable, the maximum output can be obtained. Power can be generated based on the rotational speed, and in hydroelectric power generation, power can be generated efficiently according to the flow velocity, and complicated and expensive variable pitch devices or phase adjusters can be omitted. Furthermore, synchronization with external power can be performed without an expensive synchronization device. In addition, if a switch is provided that connects another rotating shaft to the rotor shaft and switches the two phases on the input side of the stator winding, and the rotor shaft can be freely rotated forward or reversed by the switch, By operating with a voltage phase device, it can also be used as an electric brake, and by controlling the rotation speed with the voltage phase device, the braking force of the rotating shaft connected to the rotor shaft can be efficiently adjusted.

〔Effect of the invention〕

As explained above, according to the present invention, the windings wound around each of a plurality of stators are connected to a power source in parallel, and each of the conductors attached to a plurality of rotor cores is connected to a resistive material. Since the short circuit occurred through the The speed change range can be accurately set to any speed value from low speed to high stray current.

In addition, there is no need to use expensive speed control devices such as inverters and transformers, and the configuration cost can be reduced.In addition, it is easy to operate and does not generate harmonic interference, which is not possible with conventional devices. It has no significant effect.

Furthermore, it was discovered that since the resistance (A) generates a strong and unique rotational torque, the starting force leaks from the conductor to the silicon steel plate of the rotor core, reducing efficiency. Therefore, by installing an insulating material on either the conductor insertion hole provided in the rotor core or the conductor, or both, even when a strong current flows from the conductor to the resistance material as rotation torque, No starting force leaks from the conductor to the silicon steel plate of the rotor core, effectively increasing the current flowing through the resistor material and improving torque characteristics and efficiency, which is especially noticeable during startup and in low-speed rotation areas. It has a great effect.

[Brief explanation of the drawing]

1 to 13 are illustrations of embodiments of the present application. Fig. 1 is a side sectional view of the induction motor, Fig. 2 is a side view showing the rotation mechanism of the rotating stator and the blower, and Fig. 3 is a side view showing the rotation mechanism of the rotating stator and the air blower. The connected wiring diagram, Figure 4 is an example in which an insulating tube is installed in the conductor insertion hole of the rotating core, Figure 5 is a diagram showing the relationship between rotor slip and active power, and Figure 6 is a diagram showing the relationship between rotor slip and active power.
The figure is an electrical equivalent circuit diagram of the rotor, Figure 7 is an electrical equivalent circuit diagram seen from the stator side, Figure 8 is a diagram showing the relationship between torque using resistance materials, and Figure 9 is the relationship between reduced torque and slip. Figure 10 is a diagram explaining the electromotive force flowing in the conductor, Figure 11 is an example of applying insulating paint to the conductor insertion hole of the rotor core, and Figure 12 is a diagram explaining the electromotive force flowing in the conductor. FIG. 13 is a partial cross-sectional view showing the connected resistance materials, and FIG. 13 is a block diagram showing the configuration of automatic control. 1... Induction motor, 2, 3... Rotor core, 4...
・Rotor shaft, 5... Conductor, 6, 7... Short circuit ring, 8.
...Rotor, 9,9a,'9b-...Nonmagnetic core, 1
0, 11... Side part, 12... Ventilation body, 13... Cooling effect body, 13A... Cooling wing body, 14... Machine frame, 1
5.16...bearing board, 17...connecting rod, 18...
Nut, 19°20... Cooling impeller 21... Bearing,
22.23...Winding, 25...Second stator, 26.
... Sliding shaft, 27... Fixed ring, 28... Stop ring, 29... Drive device, 30... Rotating mechanism, 31... Rotating stator, 32... Magnetic sensor, 3
3... Gear, 34, 34a-34 (+... Magnetic detector, 35... Small motor, 36... Drive gear, 37... Opening, 38... Solenoid, 39...・
・Exhaust hole, 40... Ventilation hole, 41... Non-magnetic plate, 4
2... Rotation position detector, 43... Display device, 44...
・Speed detector, 45...Speed indicator, 64...Temperature detector, 65...Control 11 equipment, 66...Space part,
67... Ventilation barrel, 68... Ventilation port, 69... Ventilation outlet, 70... Ventilation barrel, 71... Windmill, 72... Motor, 73... Blower device, 74A...・Air intake port 7
4B...Exhaust port portion, 75...Center shaft, 76...Jig stand, 77...Silicon steel plate, 78...Conductor insertion hole, 7
9... Insulated chicobe, 80... Workbench, 81...
Rotor core mounting board, 82... Central shaft, 83... Servo motor, 84... Support column, 85... Paint spraying device, 86... Paint tank, 87... Support rod, 88・・・
・Heaters, 8 pieces...Spray controller, 90...Agitator, 91...Motor, 92...Spray pipe, 93...
・Mask board, 94... High resistance ring 95... Control circuit,
98...Arithmetic circuit, 99...Memory circuit, 100...
・Start switch, 1゜1...Keyboard, 102...
- Voltage phase difference setting device, 103... Voltage phase device.

Claims (5)

[Claims] (1) A plurality of conductors installed in each of a plurality of rotor cores fixed to a rotating shaft at arbitrary intervals are connected to form an integral rotor, and the plurality of conductors are connected to each other to form an integral rotor. The plurality of conductors are short-circuited and connected between the rotor cores by a resistive material, and a plurality of stators are arranged in parallel and facing each other concentrically with the plurality of rotor cores and on the outer periphery thereof, In the motor, in which at least one stator among the plurality of stators is formed into a rotatable rotary stator to form a voltage phase device, each of the windings wound around the plurality of stators is used as a power source. A drive device connected in parallel and capable of freely rotating and fixing the rotary stator is provided, and a speed detector mounted directly or indirectly on the rotor and the drive device are connected via a control device. A variable speed induction motor characterized by: (2) The variable speed according to claim (1), wherein all or part of the plurality of rotor cores is made of a non-magnetic material, and the plurality of conductors are short-circuited and connected by a resistive material between the rotor cores. induction motor. (3) A rotational position detector for detecting the rotational position of the rotational stator at the time of starting the electric motor is mounted directly or indirectly in relation to the rotational stator, and the rotational position is detected. 2. The variable speed induction motor according to claim 1, wherein the variable speed induction motor is connected to the control device. (4) a voltage induced in a conductor of a rotor facing the rotary stator by controlling the voltage phase device by the drive device activated in response to an output signal of the control device;
Patent claim (1), wherein the control device is equipped with a phase difference setting device that can change the phase difference of the voltage induced in the rotor conductor facing the stator on the other side within an arbitrary range of 0° to 180°. Variable speed induction motor as described. (5) The variable speed induction motor according to claim (1), wherein an insulating material is attached to either or both of the conductor insertion holes drilled in the rotor core into which the plurality of conductors are inserted.