JP2516398B2 - Variable speed induction motor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a variable speed induction motor having good torque characteristics and efficiency, and easy speed control.

[Prior art and its problems]

One of the methods for controlling the speed of the induction motor is to change the power supply frequency. While this method allows continuous and wide-range speed control, the frequency converter required by this method is expensive, and in the process of converting alternating current to direct current and then alternating current again by the frequency converting device, it is generally higher harmonic. Waves and radio waves may be generated, which may cause malfunctions such as malfunction of computers and other electric control devices or overheating of capacitors. Of these, harmonics measures should be taken by installing a filter. Yes, but installing a filter is expensive. It also has a drawback that performance is generally insufficient at low speeds.

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 drawback 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, the speed control can be performed continuously, but there is a drawback that the efficiency becomes poor especially in the low speed region.

The method of controlling the speed by changing the secondary resistance and changing the slip in the wire wound type motor is a relatively simple and continuous speed control method.On the other hand, the rotor winding is externally connected via a brush and a slip ring. In order to insert a resistance into the circuit, maintenance is required due to wear of the brush, and the cage type floating motor cannot change the secondary resistance for speed control.

As a means for dealing with the above problems, for example, Japanese Patent Laid-Open No.
-29005 gazette discloses the technique. This is installed in common with two sets of stators each having two independent stator windings facing the two sets of rotor cores and across the two sets of rotor cores, and short-circuited at both ends. It is equipped with a squirrel cage conductor short-circuited to each other via a ring and a high-resistor that short-circuits the squirrel cage conductors at the center of the squirrel cage conductors between the two rotor cores. This is a twin-core squirrel-cage electric motor that shifts the phases of the stator windings by 180 ° and feeds them in phase during operation after starting, but the phases of the stator windings should be shifted by 180 ° when starting. The characteristic is that the starting torque is increased to improve the starting characteristics, and the stator coils 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, since this electric motor is not a variable speed electric motor, it cannot be used as a power source of a load that requires gear shifting.

In the above-mentioned Japanese Patent Laid-Open No. 54-29005, in order to mitigate the shock caused by a rapid change in torque at the time of transition from start-up to operation, mutual feeding circuits of stator windings are momentarily connected in series. It is also possible to provide an intermediate step of 1.
As an example, in this case, the phase shift of the rotating magnetic field is 0 °.
Both the 180 ° and 180 ° points are limited to and not for gear shifting purposes. Moreover, since the voltage applied to the stator is halved by switching in series, the torque can be reduced to 1/4, and in combination with this, the shift control cannot be performed at all.
It is also clear from the fact that the subject matter disclosed in this publication is not intended for gear shifting.

In short, the one disclosed in Japanese Patent Laid-Open No. 54-29005 is tentatively "an intermediate step for switching the stator winding between series connection and parallel connection with respect to the power feeding circuit", but this series connection is completely for the purpose of shifting. It's just a useless connection.

Further, the one proposed in Japanese Patent Laid-Open No. 49-86807 is an asynchronous electric motor having a stator having a multi-phase winding and a squirrel-cage rotor, which is a conductive bar, a short-circuit end ring and a strong magnetic lamination. Consisting of a first and a second winding section, the sections being coaxially arranged next to each other and to different parts of the rotor, and supplied with alternating current of the same frequency. A non-periodic electric motor provided with means for changing the electromotive force induced in the rotor winding by the second winding section, which is two by mechanical or electrical means. Although it is possible to change the rotation speed by providing a phase difference between the stator sections, the torque is small except when the phase angle between the two stator sections is in phase, and the operation immediately starts when a load is applied. Missing to stop The practical use are those not subjected at all to have, in the connected state of the load, it was to unresolved serious problems that can not be operated as a power source for frequently repeated starting and stopping.

[Object of the Invention]

The present invention is intended to improve the above-mentioned drawbacks of the prior art. The speed control region can be set to a wide range and the speed control can be set to any desired speed steplessly, and can be started with an arbitrary torque. Another object of the present invention is to provide a variable speed induction motor with excellent torque characteristics and efficiency over the entire speed range from the starting point to the maximum rotation speed.

The variable-speed induction motor of the present invention is used by connecting to a single-phase or three-phase power source, etc., and the shape of the rotor is a normal cage type, a double cage type, a deep groove cage type, a special cage type, a winding type. Etc. can be applied to any of the above types.

[Means for solving problems]

In order to achieve the above technical object, the present invention provides a plurality of conductors communicating with two rotor cores provided on the same rotary shaft to form an integral cage rotor, Between the two rotor cores, the plurality of conductors are connected by a resistance material, and two stators are arranged side by side in a machine frame on an outer peripheral portion facing the two rotor cores. Each of the windings wound around each of the stators is connected in series,
In a motor provided with a voltage phase shifter in association with at least one of the stators, the resistance value of the resistance material viewed from the stator side is the resistance value viewed from the stator side of the rotor conductor. A solution was obtained by making the value divided by the value smaller than 25.

[Action]

According to the present invention, when a phase shift is generated between magnetic fluxes of rotating magnetic fields generated in respective stators by a voltage phase shifter of arbitrary means, a combined voltage induced in a rotor conductor according to a phase shift of magnetic fluxes. Changes and the combined voltage induced in the rotor conductor can be controlled to be increased or decreased to arbitrarily change the rotation speed of the rotor.

By the way, due to the configuration in which the plurality of conductors mounted on the two rotor cores are short-circuited between the rotor cores through the resistance material and the configuration in which the windings of the two stators are connected in series, A large current can be generated by flowing a current through the resistance material according to the deviation of the resistance value, and the resistance value of the resistance material viewed from the stator side is divided by the resistance value of the rotor conductor viewed from the stator side. We have clarified the new fact that if the division ratio is set to be smaller than 25, the speed can be stably adjusted to the low speed range near zero rotation with respect to the standard load of constant torque characteristics.

The sum of the resistance value of the rotor conductor viewed from the stator side and twice the resistance value of the resistance material viewed from the stator side divided by the resistance value of the rotor conductor is the two values. When the phase difference of the voltage is not provided between the stators of the motor, if it is set to be larger than the reciprocal of the slip value at the rated load torque of the motor, the load of constant torque characteristics and the load smaller than the rated torque Also revealed a new fact that it can operate at low speed near zero rotation and can take a large speed change range.

As a result, the torque can be stably changed over a wide range by operating the magnitude of the phase shift.

In the present invention, a variable speed induction motor having a winding type rotor, a resistance material is provided outside through a brush and a spp ring to change the secondary resistance to change the slip and to change the speed, is constituted. The characteristics are completely different. That is, in the system having the above-mentioned wound rotor and changing the resistance value of the resistance material provided outside through the brush and the slip ring, the resistance is inserted in series with the rotor conductor, so that it is a so-called proportional transition. In the variable speed induction motor of the present invention, the resistance material is inserted in parallel with the rotor conductor so that the torque characteristic is different from that of the winding type secondary resistance adjusting type.

[Embodiment] An embodiment of the present invention will be described with reference to FIGS.

An embodiment of the present invention will be described with reference to FIGS.
Reference numeral 1 (see FIGS. 1 and 3) is an induction motor, and the induction motor 1 is configured as follows. The rotor cores 2 and 3 made of an iron core are mounted on the rotor shaft 4 at an arbitrary interval, and a non-magnetic core 9 is interposed between the rotor cores 2 and 3. A plurality of conductors 5 mounted on the rotor cores 2, 3 ...
Are connected in series to form an integral rotor 8, and both ends of the plurality of conductors 5 connected in series are connected to the short-circuit rings 6 and 7. Further, the rotor cores 2, 3 and 9 are provided with a plurality of ventilation cylinders 12 ... Which communicate with both side portions 10 and 11 of the rotor 8, and a plurality of ventilation cylinders 12 ... The individual vent holes 13 ... Are drilled. The rotor 8 is a non-magnetic core portion 9 between the rotor cores 2 and 3, and is made of nichrome wire or carbon mixed steel as a connecting material that energizes each of the plurality of conductors 5 ... , Are short-circuited via a resistance material r ... such as a conductive ceramic.
(See FIGS. 1 and 2) Bearing plates 15 and 16 provided on both sides of a cylindrical machine frame 14 are integrally assembled by connecting nuts 18 to a connecting rod 17 ... Cooling impellers 19 and 20 are attached to the parts, and both ends of the rotor shaft 4 are rotatably supported by bearings 21 and 21 fitted in bearing discs 15 and 16, so that the rotor 4 is rotatable.

As described above, the non-magnetic material between the rotor cores 2 and 3 improves the torque characteristics by reducing the leak reactance, and improves the efficiency as well as between the resistance material and the rotor cores 2 and 3. It also contributes to the improvement of strength.

A first stator 24 and a second stator 25 provided with windings 22 and 23 on outer portions facing the rotor cores 2 and 3 are arranged side by side on the machine frame 14.
Between the first stator 24 and the second stator 25 and the plain bearings 26, 27
The slide bearings 26 and 27 are fixed to the machine frame 14 by the stop rings 28, and the gears 33A and 33B are fitted to one outer peripheral surface of the first stator 24 and the second stator 25. There is.
(See FIGS. 2 and 3) A drive gear 36 is mounted on a pulse motor 35 fixedly mounted on the outer periphery of the machine frame 14, and a relay shaft 29 is mounted on a bearing stand 32 mounted on the outer side of the machine frame 14. It is rotatably mounted, and the relay gear 30 and the rotation gear 31 are axially attached to both ends of the relay shaft 29, and the drive gear 36 and the rotation gear 31 are provided through the openings 37, 37 provided in the machine frame 14. And 2 are inserted into the machine frame 14, and the rotation gear 31 is set to the second position.
The drive gear 3 is engaged by engaging the gear 33B fitted on the stator 25.
6 is engaged with the gear 33A fitted to the first stator 24, and the relay gear 30 is engaged with the interlocking gear 34 integrally formed with the drive gear 36, so that the first stator 24 and the second stator 24 The stator 25 and the rotor 8 are concentrically and rotatably formed, and the first stator 24 and the second stator 25 form a voltage phase shifter 38 to form a variable speed induction motor. Reference numeral 39 is an exhaust hole, and 40 is a ventilation hole formed in the bearing disks 15 and 16 in plural numbers.

Next, the connection of the windings 22 and 23 wound around the first stator 24 and the second stator 25 will be described. (See Fig. 4)
The first and second stators 24 and 25 are connected in series with the windings 22 and 23 each having a star connection. That is, the terminals A, B, C of the winding wire 22 of the first stator 24 are connected to the commercial three-phase power supplies A, B, C, and the terminals a, b, c of the winding wire 22 of the second stator 25 are connected. Winding 23 terminals
The terminals a, b and c of the winding wire 23 are short-circuited and connected to A, B and C.

 The operation of the above configuration will be described below.

When the winding 22 of the first stator 24 is energized from a commercial three-phase power source, a rotating magnetic field is generated in the stators 24 and 25, a voltage is induced in the rotor 8, and a current flows through the conductors 5 of the rotor 8. Rotor 8
Rotates. When the rotation amount of each of the second stators 25 with respect to the first stator 24 is set to zero, each of the stators 2
There is no phase shift in the magnetic flux of the rotating magnetic field generated in 4,25, and since the current does not flow in the resistance material r, which is the connecting material, as will be described later in detail, it has the same torque characteristics as a general induction motor. Is.

Next, the pulse motor 35 is actuated to rotate the first stator 24 and the second stator 25 in opposite directions, and the phase difference angle is θ.
Only the case of rotating only will be described. The phases of the magnetic fluxes φ ₁ and φ ₂ of the rotating magnetic field formed by the first stator 24 and the second stator 25 that form the voltage phase shifter 38 are shifted by θ, and therefore the first stator 24 and the second stator 25 The phases of the voltages ₁ and ₂ induced in the conductors 5 of the rotor 8 are deviated by θ due to the rotating magnetic fields. Now, with reference to the voltage ₂ induced in the conductors 5 of the rotor 8 by the rotating magnetic field of the second stator 25,
₂ = SE Here, S is the slip and E is the induced voltage at slip 1. At this time, the voltage ₁ induced in the conductor 5A by the rotating magnetic field of the first stator 24 is ₁ = SE _ε ^jo .

(E = Induced voltage when slip 1) FIG. 5 shows the rotor 8 in the case where the resistance material r ... Short-circuiting the plurality of conductors 5 ... Is not mounted in the non-magnetic core 9. It shows the relationship between the slip S and the active power P of the rotor input, and the phase of the voltage induced in the rotor is θ.
The active power P is maximum when = 0 °, and 0 ° <θ <180
At °, it is smaller than that. Conductor 5 here
When the resistance and the inductance of ... Are R and L and the angular frequency of the power source is ω, the maximum of the active power P appears when S = (R / ωL).

Since the active power P is proportional to the drive torque of the induction motor 1, the pulse motor 35 is operated to activate the first phase of the voltage phase shifter 38.
By rotating the stator 24 and the second stator 25, the voltage induced in the rotor 8 can be adjusted and the speed of the rotor can be controlled steplessly.

Next, let R ₁ and R ₂ be the resistances from the short-circuiting rings 6 and 7 of the conductors 5 of the rotor 8 to the connecting material, or let L ₁ and L ₂ be the inductances, and let ω be the angular frequency of the power supply. If the resistance of the resistance material that short-circuits each of the conductors 5 is r, then the rotor 8
The electrical equivalent circuit of is as shown in FIG. 6, and the symbols I ₁ , I ₂ , I
₃ shows the current flowing through each branch.

Next, by converting the one shown in FIG. 6 into an equivalent circuit viewed from both stators 24 and 25, the result becomes as shown in FIG. 7, where R ₁ = R ₂ , L
_{When 1} = L ₂ and θ0 °, I ₃ = I ₁ −I ₂ = 0 and no current flows through the resistance material r. This means θ =
At 0 ° it means that the torque T is equal to the value without r. Therefore, when θ = 0 °, it has the same torque characteristics as the conventional induction motor.

Next, when R ₁ = R ₂ and 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 in the conventional induction motor is R ₁ + R ₂ = R, then R will increase to R + 2r. ing.

By the rotation of the rotor 8, the outside air is sucked into the machine frame 14 by the cooling impellers 19 and 20 from the ventilation ports 40 formed in the bearing disks 15 and 16, and the first by the cooling impellers 19 and 20. , The second stator 24,2
5, the rotor cores 2, 3, the conductors 5 ..., the resistance material r ... are cooled by the air that flows through the windings 22 and 23 to cool and the air that flows through the ventilation holes 12 ... Each function works stably. The rotation of the first and second stators 24, 25 is performed by rotating the pulse motor 35 in the forward and reverse directions with a switch. However, the rotation is not limited to the pulse motor 35, and other forward / reverse rotation motors or gas can also be used. , Any drive device such as a servo mechanism using a liquid cylinder can be diverted, and there is also a case where it is operated by a manual handle and a case where only one of the first stator 24 and the second stator 25 is rotated. . Then, the rotation of the stator is released or locked by an arbitrary operating mechanism in association with the operation of the rotation drive device of the stator.

Next, the operation of connecting the windings 22, 23 wound around the first stator 24 and the second stator 25, respectively, in series will be described.

Since the windings 22 and 23 are connected in series, the commercial three-phase power source inputs the winding 22 and the current flows between the windings 22 and 23. Even if there is a difference or a difference in the magnitudes of the capacities of the two stators 24 and 25, the magnitudes of the currents flowing through the respective windings 22 and 23 are equal regardless of the difference, and therefore, the first stator 24 and the second stator The action of equalizing the magnitudes of the currents induced by the rotating magnetic fields of the stator 25 in the conductors 5 of the rotor 8 and the voltage phase shifter.
According to the difference in rotation between the first stator 24 and the second stator 25 of 38, that is, the phase shift generated between the magnetic fluxes of the rotating magnetic field, both stators 24, 2
The action of forcing the currents flowing in the conductors 5 of the rotor 8 to become equal by the respective rotating magnetic fields of 5 and the conductors of the rotor core facing the stators 24 and 25 are induced. Due to the synergistic effect with the action of generating a forcing force, the current of the vector difference caused by the phase difference of the voltage inevitably flows through the resistance material r ... Each of the plurality of conductors 5 serving as a connecting material. As shown in FIG. 8, it is possible to improve efficiency and generate a large torque in each speed change range, such as slip and torque characteristics, and facilitate starting in each speed range even when a load is connected. Thus, it is possible to arbitrarily use the power source such as a smooth start according to the load start characteristic or a high output start, and it is possible to optimally cope with a power source that frequently repeats start and stop. As described above, in the speed change of the rotor 8, the voltage phase shift device 38 controls the shift of the phase shift to allow the conductor 5 of the rotor 8 to move.
The rotational speed of the rotor 8 can be arbitrarily changed only by the control that increases or decreases the current that is induced by flowing.

It should be noted that, with respect to the magnitude of the current flowing through the conductors 5 of the rotor 8 due to the rotating magnetic fields of the first stator 24 and the second stator 25 in which the windings 22 and 23 are connected in series, a plurality of conductors 5 …
The ratio of the current flowing in a short circuit between the resistance materials r ...
Resistance material r ... Pθ (P = irrespective of resistance value and slip
It is determined by the value of the number of pole pairs, θ = phase angle, and if Pθ is constant (the above ratio is maximum at Pθ = π and becomes zero at Pθ = 0), the secondary insertion of a general wire wound induction motor is performed. The slip and torque characteristics are the same as when the resistance is constant,
When Pθ becomes small, the ratio of the current flowing through the conductors 5 of the rotor 8 becomes small, and making Pθ small has the same effect as making the secondary insertion resistance of a general wire wound induction motor small. Become. When the rated current is applied to both the stators 24 and 25, the rated current and rated torque characteristics of the maximum speed will depend on the selected slip value and the design of the resistance value of the connecting material even if the phase difference θ is changed arbitrarily. And can be acted on at substantially the same time in the respective shift regions. Further, even if the windings 22 and 23 of the first and second stators 24 and 25 are connected in series, if one of the conductors 5 is not short-circuited without providing a connecting member, one of the fixings is fixed. Stator conductor 5 facing the child
Almost no voltage is induced in.

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

(Refer to FIG. 1) A speed detector 60 such as a tachogenerator having a speed indicator 61 on the input side of a control device 55 comprising an input / output control circuit 56, a control circuit 57, an arithmetic circuit 58, a memory circuit 59 and the like.
And a stator rotation position detector 62 such as a magnetic sensor, and a machine frame
An electromagnet that connects a temperature detector 63 mounted at a proper position in 14 and a keyboard 64 equipped with a display, and locks or releases the rotation of the pulse motor 35 and the rotation side stator on the output side of the control device 55. 65, windings 22, 23, conductor 5, ..., resistance material r
It is connected to the electric motor 66 that drives the blower that blows the air for cooling etc. from the proper place of the machine frame 14, and the following control values are input from the keyboard 64 to the memory circuit 59 of the control device 55. There is. That is, the rotation amount of the stator with respect to the phase difference angle of 0 ° to 180 °, the pulse control value of the pulse motor 35 with respect to the rotation amount of the stator, and the position detector 62 of the stator with respect to the phase angle of 0 ° to 180 °. The relationship and the temperature reference value for cooling the inside of the machine casing 14 are entered, and the keyboard 64
When the speed control value of the rotor shaft 4 is input from the controller to the control device 55, the rotation amount of the stator is calculated to obtain the input speed control value, and the pulse motor corresponding to the rotation amount of the stator is calculated.
35 pulse control values are calculated. The electromagnet 65 is operated by the signal output from the control device 55 to unlock the stator, and the pulse motor receives the signal from the control device 55.
35 is operated to control the speed change, and the speed value communicated with the detection value of the speed detector 60 mounted on the rotor shaft 4 is compared with the speed control value. Is output to the pulse motor 35 to correct and control the rotation speed, and the rotation of the stator is locked by the electromagnet 65.

When the temperature detection value of the temperature detector 63 communicated to the control device 55 becomes higher than the temperature reference value set in the memory circuit 59, a signal output from the control device 55 causes a motor of the blower.
66 is started, and air is blown into the machine casing 14 to wind the windings 22, 23, the conductor 5, ...
The resistance material r ... Is cooled. Keyboard while driving
When a new rotation speed value is input from 64 or a speed control value is automatically input to the control device 55 directly from the control panel connected to the load via the keyboard 64, the stator rotation position detector 62 Based on the current position of the contacted stator, the pulse value for operating the pulse motor 35 is calculated for the desired speed value, and the electromagnet 65 and the pulse motor 35 are operated by the output signal from the controller 55 to rotate. Control the speed.

The output side of the control device 55 may be connected to a pole number changeover switch 68, a phase changeover switch 69, etc., and may be automatically controlled according to the speed control value input to the control device 55.
In some cases, the air cooling device 67 is connected to the blower, and the air cooling device 67 acts on the temperature reference value set in the control device 55.

By the way, Fig. 10 to Fig. 17 show the resistance value of each rotor conductor (combined in parallel of multiple rotor conductors) and each resistance material when windings of multiple stators are connected in series. It represents the relationship between the resistance value of S, and the slip and torque at each phase difference.

Generally, the type of load that the reaction torque increases at low speed, the type of load that decreases from high speed to low speed such as fan and pump, and the load of constant torque characteristic from high speed to low speed in principle There is. And
If the slip and torque characteristic curves of the variable speed motor and the torque characteristic curve of the load intersect at a position where the torque tends to decrease as the slip increases, the speed changes as the load changes. Unstable fluctuations occur.

Therefore, in order to perform stable speed control of the load of the constant torque characteristic that is the standard load, the torque does not change substantially as the slip increases, or the torque curve of the load shows a tendency to increase at a position where the torque tends to increase. Need to meet.

In FIGS. 10 to 17, R ₂ is a numerical value representing the resistance of the rotor conductor viewed from the stator side, R ₃ is a numerical value representing the resistance of the resistance material viewed from the stator side, and R ₃ for R ₂
If the value divided by is 25 or less, the torque does not change substantially as the slip increases, or the condition that the load torque curve intersects at the position of increasing tendency is satisfied,
Stable wide-range speed control is possible for a constant torque characteristic load that is a standard load, and it can be used very effectively as a variable speed induction motor.

In the present invention, if the two stator windings are connected in series and connected to a power source, a resistance material for short-circuiting the rotor conductors between the rotor cores is provided. If there is no phase difference, it is good if the phase difference is 0 °. However, if the phase difference is provided, almost no voltage is induced from one stator to the corresponding rotor conductor portion, and if a load is applied, the motor will stop. Sometimes. The fact that no resistance material is provided means that the resistance is close to infinity. Even if the resistance material is provided, if the resistance value is very large, a phenomenon similar to the above will occur. .

In short, in the variable speed induction motor having the configuration of the present invention, if the resistance value of the resistance material is too large, the torque characteristic becomes poor, and it becomes impossible to shift a wide range of loads having a constant torque characteristic which is a standard load. .

The cause of such characteristics will be further examined as follows. That is, when the phase difference θ is provided, a phase difference occurs between the voltages induced in the corresponding portions of the rotor conductor. However, if the resistance value of the resistance material is too large, it becomes difficult for the current to flow for a certain phase difference, and the equivalent reactance increases and the power factor deteriorates.

In the present invention, the relationship between the resistance value of the rotor conductor and the resistance value of the resistance material is clarified by using an experiment based on the clarification of the above new fact.

It should be noted that the present invention is not a variable speed motor that controls the speed over a wide range, but it is started by suppressing the starting current when starting and obtaining a large torque, and after the start, the phase difference is made small or zero. It can also be applied to a startability improving motor, which enables stable acceleration or deceleration for the same reason as described above.

By the way, it goes without saying that the torque characteristics differ when a phase shift is caused by the resistance value of the rotor conductor and the resistance value of the resistance material, but the resistance value of the rotor conductor viewed from the stator side and the A value obtained by dividing the sum of the resistance value of the resistance material viewed from the stator side and twice the resistance value of the rotor conductor by the resistance value is not provided between the plurality of stators. when the phase difference θ of the voltage to 180 ° by equalizing the principle reciprocal value S ₁ of the sliding in at the rated load torque T ₁ of the motor, the slip S and the torque T
The new fact was clarified that the torque when the slip S = 1 in the characteristic graph showing the relationship of ₁₎ becomes equal to the rated torque T ₁ .

FIG. 18 is a characteristic diagram when the resistance value of the rotor conductor and the resistance value of the resistance material are determined as described above, and FIG. 19 is the resistance value of the rotor conductor viewed from the stator side and from the stator side. The rated value of the electric motor in the case where a value obtained by dividing the sum of the resistance value of the resistance material and twice the resistance value by the resistance value of the rotor conductor does not provide a voltage phase difference between the two stators. a characteristic diagram when less than the value S ₁ of the sliding in at the load torque T _1, the variable speed range becomes narrower, of course the low-speed range near zero rotational load of the constant torque characteristic, which is a standard load You will not be able to rotate it.

On the other hand, FIG. 20 is a diagram showing an embodiment of the present invention in which the sum of the resistance value of the rotor conductor viewed from the stator side and the resistance value of the resistance material viewed from the stator side is doubled. The value divided by the resistance value of the conductor is set to be larger than the reciprocal of the value of the slip S ₁ in the rated load torque of the electric motor when the phase difference of the voltage is not provided between the two stators. In the characteristic diagram of the case, a load having a constant torque characteristic which is a standard load and a load smaller than the rated torque T ₁ can be operated in a low speed range near zero rotation and a large speed change range can be set, so that a variable speed motor can be obtained. It was able to be excellent.

〔The invention's effect〕

As described above, according to the present invention, a plurality of conductors mounted on each of two rotor cores are connected to each other to form an integral rotor. In, connecting the plurality of conductors by a resistance material,
Concentric with the two rotor cores and 2
The two stators are arranged side by side and the windings of the two stators are connected in series to be connected to a power source, and at least one of the two stators has a voltage. Since a phase shifter was provided and the resistance value of the resistance material viewed from the stator side was divided by the resistance value of the rotor conductor viewed from the stator side to be smaller than 25, it was a standard load. The unstable region of speed control against the load of torque characteristics disappeared, and stable wide-range speed control became possible.

The sum of the resistance value of the rotor conductor viewed from the stator side and twice the resistance value of the resistance material viewed from the stator side divided by the resistance value of the rotor conductor is the two values. Since it is set to be larger than the reciprocal of the slip value at the rated torque of the motor when the phase difference of the voltage is not provided between the stators, the constant torque characteristic load is also applied to the load smaller than the rated torque. It became possible to operate at a low speed near zero rotation and to have a large speed change range, and the speed control became stable over a wide range.

[Brief description of drawings]

1 to 20 are views showing an embodiment of the present invention, FIG. 1 is a side sectional view of an induction motor, FIG. 2 is a side view showing a rotating mechanism of a stator, and FIG. 3 is a stator. 4 is a partially broken side view showing the rotating mechanism of FIG. 4, FIG. 4 is a connection diagram in which the windings wound around the stator are connected in series, and FIG. 5 shows the relationship between the slip of the rotor and the active power. Fig. 6 is an electrical equivalent circuit diagram of the rotor, Fig. 7 is an electrical equivalent circuit diagram viewed from the side of the stator, and Fig. 8 is a stator in which each of a plurality of conductors is short-circuited by a resistance material. FIG. 9 is a torque characteristic diagram showing the relationship between speed and torque when the windings wound on the coil are connected in series, FIG. 9 is a block diagram showing the configuration of automatic control, and FIGS. 10 to 20 are torque characteristic diagrams. 1 ... Induction motor, 2,3 ... Rotor core, 4 ... Rotor shaft, 5 ... Conductor, 6,7 ... Short-circuit ring, 8,8A-8C ... Rotor, 9 ... Non-magnetic Core, 10,11 …… side part, 12 …… ventilator, 13 …… vent hole, 14 …… shaft, 15,16 …… bearing panel, 17…
… Connecting rod, 18… Nut, 19,20… Cooling impeller, 21…
… Bearing, 2,23 …… Winding, 24 …… First stator, 25 …… Second
Stator, 26,27 …… Slip shaft, 28 …… Stop ring, 2
9 …… Relay shaft, 30 …… Relay gear, 31 …… Rotation gear, 3
2 …… Bearing stand, 33A, 33B …… Gear, 34 …… Bolt, 35…
… Pulse motor, 36 …… Drive gear, 37 …… Opening,
38 …… Voltage phase shifter, 39 …… Ventilation hole, 40 …… Ventilation hole, 55
...... Control device, 56 ...... Input / output circuit, 57 ...... Control circuit, 58
...... Arithmetic circuit, 59 …… Memory circuit, 60 …… Speed detector, 61
...... Speed indicator, 62 …… Stator rotation position detector, 63 ……
Temperature detector, 64 …… keyboard, 65 …… electromagnet, 66 ……
Electric motor, 67 ... Air cooling device, 68 ... Number of poles changeover switch, 69 ... Phase changeover switch.

Claims (2)

(57) [Claims] 1. An integral squirrel-cage rotor is provided by mounting a plurality of conductors communicating with two rotor cores mounted on the same rotating shaft with a space or a non-magnetic material provided at arbitrary intervals. Then, the plurality of conductors are connected by a resistance material in the space or the non-magnetic body, and concentrically with the two rotor cores,
In addition, two stators are provided side by side on the outer periphery of the stator,
A rotor in which the windings of a plurality of stators are connected in series, and which faces one of the two stators in relation to at least one of the two stators. In a motor provided with a voltage phase shifting device that causes a phase difference between a rotating magnetic field generated around the rotor and a rotating magnetic field generated around the rotor facing the other stator, a resistance material viewed from the stator side. The variable speed induction motor is characterized in that a value obtained by dividing the resistance value of 1 by the resistance value of the rotor conductor viewed from the stator side is smaller than 25. 2. An integral squirrel-cage rotor is provided by mounting a plurality of conductors communicating with two rotor cores mounted on the same rotating shaft with a space or a non-magnetic material provided at arbitrary intervals. Then, the plurality of conductors are connected by a resistance material in the space or the non-magnetic body, and concentrically with the two rotor cores,
In addition, two stators are provided side by side on the outer periphery of the stator,
A rotor in which the windings of a plurality of stators are connected in series, and which faces one of the two stators in relation to at least one of the two stators. In a motor provided with a voltage phase shifting device that causes a phase difference between a rotating magnetic field generated around the rotor and a rotating magnetic field generated around the rotor facing the other stator, the rotor viewed from the stator side. A value obtained by dividing the sum of the resistance value of the conductor and the resistance value of the resistance material viewed from the stator side by the resistance value of the rotor conductor is the phase difference of the voltage between the two stators. The variable speed induction motor is characterized in that it is larger than the reciprocal of the value of slip at the rated load torque of the electric motor in the case of not providing.