JPS62260590A - Induction motor - Google Patents

Abstract

PURPOSE:To control a rotor speed to an arbitrary speed by rotationally operating a rotation side stator relative to another stator immovably mounted on a machine frame so as to vary a position of rotating magnetic field. CONSTITUTION:There are arranged a first stator 24 and a second stator 25 provided with windings 22, 23 on the outside facing rotor cores 2, 3. A rotation of the second stator 25 is locked by a bolt 34 of the machine frame 14. A gear 33 is fitted on the outer peripheral face of the first stator 24, a worm gear 36 is journaled to a shaft of a pulse motor immovably mounted on the outer periphery of the machine frame 14 and then inserted from an opening 37 of the machine frame 14 to engage with the gear 33, and the first stator 24 is made to freely rotate concentrically with a rotor 8.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an induction motor with good torque characteristics and efficiency and easy speed control.

Prior art and its problems One method of controlling the speed of an induction motor is to change the power supply frequency. Although this method allows for continuous and wide-range speed control, the frequency converter required by this method is expensive, and the process of converting alternating current to direct current and then converting it back to alternating current with the frequency converter generally requires high frequency adjustment. Waves and radio waves are generated, which can cause problems such as malfunction of computers and other electrical control equipment or overheating of capacitors. Measures against harmonic interference can be taken by installing filters. However, installing a filter is expensive. Additionally, they have drawbacks such as generally insufficient performance at low speeds.

Furthermore, the method of controlling the speed by changing the number of poles of the electric motor has the disadvantage that even though the speed can be changed stepwise by changing the number of poles, it is not possible to control the speed steplessly and smoothly.

Further, although the method of controlling the speed by changing the voltage of the power supply allows the speed to be controlled continuously, it has the disadvantage that the efficiency is poor especially in the low speed range.

In wire-wound motors, the method of controlling the speed by changing the secondary resistance and changing the slip allows continuous speed control with relative ease. Inserting a resistor into the circuit requires maintenance and inspection due to brush wear, and squirrel cage blade conductive motors have the disadvantage that speed control cannot be performed by changing the secondary resistance.

OBJECTS OF THE INVENTION The present invention improves the drawbacks of the prior art described above, and provides an induction motor that can continuously control the speed over a wide range of speeds and has good torque characteristics, especially in the low speed range. There is a particular thing.

The induction motor of the present invention is used by being connected to a single-phase or three-phase power source, etc., and the rotor has a normal squirrel cage shape and a 2 m
It can be applied to any type of cage type, deep groove cage type, special cage type single winding type, etc., and the conductor used in the explanation of the present invention refers to the conductor installed in the squirrel cage rotor core, and This is a general term for each of the windings wound around the wound rotor core.

Means for Solving the Problems In order to achieve the above object, the present invention provides a plurality of stators having windings arranged in parallel at an arbitrary interval, and at least one of the plurality of stators. the pieces are fixed to the machine frame, and at least one piece is formed so as to be rotatable concentrically with the rotor shaft,
A plurality of rotor cores are disposed on an inner peripheral surface facing the plurality of stators and mounted on the rotor shaft, and each of the plurality of conductors respectively installed on the plurality of rotor cores is When an arbitrary voltage is applied to each of the plurality of conductors in the space or non-magnetic core portion of the plurality of rotor cores that are connected to form an integral rotor and do not face the stator, each of the plurality of conductors is energized. This problem was solved by creating a short circuit through the connecting material.

Operation With the above configuration, when electricity is applied to the stator fixed to the machine frame and the stator that can freely rotate concentrically with the rotor, the rotating magnetic field induces a voltage in the rotor, and the rotor core Electric current flows through the conductors installed in the rotor, causing the rotor to rotate. When the rotation of the rotary stator relative to the stator fixed to the machine frame is zero, there is no difference in the phase of the rotating magnetic field between the stators.
Since no current flows through the coupling material, it exhibits the same torque characteristics as a general induction motor, but when the rotary side stator is rotated, the phase of the rotating magnetic field generated between it and the stator fixed to the machine frame changes. As the deviation of It becomes smaller and the torque also becomes smaller.

As the rotational speed of the rotor decreases, the shear rate increases and the power factor decreases.

However, since each of the plurality of conductors is short-circuited at a position that does not face the stator via a connecting member that conducts electricity when a given voltage is applied, there is a phase shift in the rotating magnetic field as the rotating stator rotates. This causes a phase shift between the voltage induced in the rotor conductor in the part facing the stator fixed to the machine frame and the voltage induced in the rotor conductor in the part facing the rotating stator. Then, a voltage is applied to the connecting member, causing a short circuit between the plurality of conductors through the connecting member, and a current flows, thereby improving the power factor and ensuring a large torque in the low-speed rotation region.

Example Embodiments of the present invention will be described based on FIGS. 1 to 19.

Reference numeral 1 shown in FIGS. 1 and 2 is an induction motor,
The induction motor 1 is constructed as follows. The rotor core 2.3 consisting of an iron core is attached to the rotor shaft 4 with an arbitrary interval.
A non-magnetic core 9 is interposed between the rotor cores 2 and 3.

Each of the plurality of conductors 5 installed in the rotor cores 2 and 3 is connected in series to form an integral rotor 8, and the plurality of conductors 5 connected in series are connected in series. Both ends are connected to short circuit rings 6.7. In addition, a plurality of ventilation holes are connected to the rotor cores 2 and 3.9 to both sides 10.11 of the rotor 8.
412... are provided, and a plurality of ventilation holes 13... are bored perpendicularly to the outer circumference of the rotor 8 from the ventilation barrels 12.... As shown in FIG. 3, the rotor 8 has a non-magnetic core 9 between the rotor cores 2 and 3 using nichrome as a connecting material that conducts electricity when a given voltage is applied to each of the plurality of conductors 5. Resistance materials such as wire, carbon-containing steel, etc.
It is shorted through. (See Figure 1 and ?JS2 figure)
Bearing discs 15 and 16 provided on both sides of the cylindrical machine frame 14 are fastened to the connecting rods 17 with nuts 18, and assembled integrally, and cooling W wheels are installed on both sides of the rotor 8. 19.20, both ends of the rotor shaft 4 are supported by bearings 21.21 fitted in the bearing disc 15.16, and the rotor 4 is rotatable.

A first stator 24 and a second stator 25 having windings 22° 23 are disposed on the outside facing the rotor cores 2 and 3, and the machine frame 1
4 and the first stator 24. A sliding bearing 26.27 is installed between the second stator 25, and the sliding bearing 26.27 is connected to the machine frame 1.
4, a movement prevention ring 32 is fitted to the outer periphery of one side of the second stator 25, and the second stator 25 is screwed to the machine frame 14 with bolts. Rotation is locked by 34.

Fit the pin t7-33 on the outer peripheral surface of one side of the first stator 24,
A worm gear 36 is pivotally attached to a pulse motor 35 fixed to the outer periphery of the machine frame 14, and the worm gear 36 is inserted through an opening 37 of the machine frame 14 and engaged with the gear 33, and the first stator 24 is rotatable concentrically with respect to the rotor 8. 38 is a cover provided on the opening 37, 39 is an exhaust hole, and 40 is a plurality of ventilation holes bored in the bearing plate 15, 16.

The operation of the above configuration will be explained below.

1st. When the windings 22 and 23 of the second stator 24.25 are energized, a rotating magnetic field is generated in the stator 24.25, a voltage is induced in the rotor 8, and a current is generated in the conductors 5 of the rotor 8. The flow causes the rotor 8 to rotate.

When the amount of rotation of the first stator 24 with respect to the second stator 25 is set to zero, the winding 2 of each stator 24.25
2. There is no phase shift of the rotating magnetic field input to 23, and as the details will be explained later, no current flows through the resistive material r... which forms the connecting phase, so the torque characteristics are the same as those of the general induced electric motor. It is something that has.

Next, a case where the first stator 24 is rotated by a phase angle of θ with respect to the second stator 25 will be described. First stator 2
4 and the rotating magnetic field generated by the second stator 25...flux φ1. The phase of φ2 is shifted by θ, so the phase of ``upper pressure 6+, (=2) induced on the conductor 5 of the rotor 8 by the first stator 24 and the second stator 25 is shifted by θ. Currently,
The voltage 02 induced in the conductor 5 of the rotor 8 by the second stator 25 is used as a reference, and the voltage is set as e2=SE. Here, S is slip and E is the induced voltage when slip is 1. The voltage 91 induced in the conductor 5A by the first stator 24 is as follows.

e+=sEεje.

(E = induced voltage when slip is 1) What is shown in Fig. 4 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 slip S of the rotor 8 and the active power P of the rotor input. When θ = 0°, the active power P is maximum, and when 0° < θ < 180°, it is smaller. Become something. Here, the resistance and inductance of the conductor 5... are R and L, and the angular frequency of the power source is ω
Then, 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 speed can be continuously controlled by rotating the first stator 24.

Next, let R1 and R2 be the respective resistances from the short-circuit rings 6.7 of the conductors 5 of the rotor 8 to the connecting members, let Ll and L2 be the inductances, let ω be the angular frequency of the power supply, and let each conductor 5 If the resistance of the resistive material that short-circuits each of . I3 indicates the current flowing through each branch.

Next, when converting the circuit not shown in Fig. 5 into an equivalent circuit seen from both stators 24 and 25 side, it becomes as shown in Fig. 6, and RI=R
2, 13=I+-12 at LI=L2 and θ=0°
= 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, when R+=R2, LI=L2 and θ=180°, I+=-12, l3=I+-12=211,
In a conventional induction motor, the resistance of the rotor shaft is RI=R
If 2=R, the result is the same as if R were increased to R+2r.

From the above results, the torque characteristics range from S=1.0 to S-
In the range of O, as shown in FIG. 7, the first stator 24
If you change the phase angle by rotating , the torque will change.

Now, if the reaction torque of the load connected to the rotor shaft 4 of the induction motor 11 is Tr shown in FIG.
By changing the rotation angle θ of the rotor 8, the slip of the rotor 8 can be reduced by 8
1 to 82, that is, the rotational speed of the rotor 8 can be changed. Furthermore, by changing the set value of the resistance r, the speed range of the rotor 8 can be further expanded, and a large torque can be generated during low speed rotation.

Next, with reference to FIG. 8, another embodiment of a rotor in which a diode is used as a connecting member for short-circuiting each of a plurality of conductors will be described. 'l! installed in rotor cores 2 and 3! Each of the 2a conductors 5 is connected in series to form an integral plurality of conductors 5..., and both ends of the plurality of conductors 5... are connected to a short-circuit ring for integral rotation. A child 8A is formed, and the first. In the non-magnetic core 9 portion between the rotor core 2.3 that does not face the second stator 24.25, a connecting member that connects and short-circuits each of the plurality of conductors 5 is operated at an arbitrary voltage value. A set of constant voltage diodes D connected in series with opposite polarity...
・It is a binding. The electrical tongue: 1ilIi circuit is as shown in Fig. 9, and when the phase angle θ operated by the first stator 24 is 180 @ and R1 = R2°L + = 1-2, I'1 = -I2. , when a pair of constant voltage diodes D... inserted in the path where the electric circuit is short-circuited are energized, a current of l3=II-I2=2I+ flows, so a large torque is generated even at θ-180°. can be produced.

FIG. 10 shows the torque characteristics in this example. The curve shown by the solid line is the torque characteristic when the connecting material to be short-circuited is connected to a pair of diodes D... This is the torque characteristic in the low speed region when each of 5... is not short-circuited. As can be seen from this torque curve, when θ=θ°, multiple conductors 5...
No current flows through a pair of constant voltage diodes D, which are used as connecting members to short-circuit each of the -, and the torque characteristics are the same as those of the - installed motor, and the torque characteristics are different in the low-speed rotation region at each phase difference. At the same time, efficiency is also greatly improved.

What is shown in FIG. 11 is another embodiment of a rotor in which a resistive material and a set of diodes are directly connected as connecting members for short-circuiting each of a plurality of conductors.

Each of the plurality of conductors installed in the rotor core 2.3 is connected in series to form an integral plurality of conductors 5, and both ends of the plurality of conductors 5 are short-circuited. to form an integral rotor 8B. Second stator 24.25
In the non-magnetic core 9 portion between the rotor cores 2 and 3 that do not face each other, a nichrome wire that becomes energized when an arbitrary voltage is applied serves as a connecting material that connects and short-circuits each of the plurality of conductors 5. Resistance materials such as iron roam wire, carbon-containing W4, etc.
. . . and at least one set of constant voltage diodes D.
...and are connected in series.

The electrical equivalent circuit in this embodiment is as shown in FIG. is applied and the voltage value becomes larger than the voltage value set for the diode D..., the plurality of conductors 5...
A current is short-circuited and flows through each of the resistive materials r... and the set of voltage regulator diodes D..., and the first
As shown in the torque curve shown in Figure 3, a resistive material r... which short-circuits each of the plurality of conductors 5... during low speed rotation.
Torque values T1 to T4 at each phase difference are shown by dotted lines when a set of diodes D... are not provided in series with
On the other hand, when a resistive material r... and a set of constant voltage diodes D... are provided as connecting members, the torque l1lIT+'~T4' at each phase difference becomes large, and even in the low speed rotation region, the torque l1lIT+'~T4' becomes large. to secure the market. It should be noted that the series connection of the resistive material r and the set of constant voltage diodes D may be reversed from the embodiment diagram and C may be used.

Next, FIG. 14 shows still another embodiment of a rotor in which a resistive material and a pair of diodes are arranged in parallel as connecting members for short-circuiting each of a plurality of conductors.

A plurality of conductors 5 installed in communication between the rotors 2 and 3...
・ for each of the 1st. In the non-magnetic core 9 portion that does not face the second stator 24° 25, a short-circuiting connecting member is provided in parallel with a resistor r... and a set of constant voltage diodes D... connected in series with opposite polarity. However, it is formed in the rotor 8C which is integral with the rotor 8C.

The electrical equivalent circuit in this embodiment is as shown in FIG. 15, in which the phase difference between the voltages induced in the conductors 5 of the rotor 8 gradually increases as the first stator 24 rotates. From this point on, a short circuit occurs to the resistive material ``...'', and a current flows, and the resistive material r.
The power factor is improved by the action of ..., and the voltage phase shift becomes large, and when current flows through a pair of constant voltage diodes D connected in series with opposite polarities, the torque characteristics in the low speed region change. The torque curve is shown in FIG. 16. The torque characteristics in this example are the same as those in the example (not shown in FIG. 3) while the set of constant voltage diodes D... are not energized, and the voltage is applied to the set of constant voltage diodes D... The characteristic is that when the current is applied and the current is applied, the characteristics become close to those of the embodiment shown in FIG. One of them should be selected and adopted after consideration.

Next, the connections connecting the wound rotor and the windings will be explained with reference to FIGS. 17 and 18.

Two rotor cores 41 and 42 made of iron core on the rotor shaft 4
is mounted so as to face the first stator 24 and the second stator 25, windings 43, 44 are applied to the rotor core 41, 42,
As shown in FIG. 18, in a circuit 45 that connects the conductor and the windings 43 and 44 in series, diodes D connected in series with opposite polarities are interposed to connect the windings. A short circuit may be made, and if necessary, a resistive material r... may be connected in series to the constant voltage diode D. Winding wires 43, 44.
A cover 46 made of a non-magnetic material is attached to the connecting portion 45 to prevent the diode D... and the resistance material r... from being swung out due to the centrifugal action accompanying the rotation of the rotor 47, forming an integral rotor 47. It is. The rotor cores 41, 42 have a plurality of ventilation holes 15148 passing through each end thereof.
, 49 . . . , and a plurality of exhaust holes 50 . The configuration other than the above is the same as in FIGS. 1 and 2, and each winding 43.
The connection material that short-circuits the circuits 45 of 44 is connected to a pair of constant voltage diodes D..., and its effect is the same as that of the embodiment shown in FIG. Since the effect when a set of constant voltage diodes D... are connected in series is the same as that in the embodiment shown in FIG. 11, detailed explanation thereof will be omitted.

In addition, in the description of each of the above embodiments, only the first stator 24 was explained as being rotatable, but instead of the second stator 24, the second stator 25 may be configured to be rotatable. The same effect is applied to 1q, and the number of stators and rotors is not limited to only two, but it is possible to provide a plurality of stators and rotors and fix any number of stators to the machine frame. It is possible to freely select an arbitrary number of stators depending on the capacity, purpose, etc. of the electric motor. Although the operation has been described with reference to the case where the first stator 24 and the second stator 25 have the same capacity M, the capacity of either stator may be increased.

Furthermore, it goes without saying that either star connection or delta connection can be selected for the windings applied to the rotor J3 and the rotor core, and the diodes interposed in the electric circuit formed by the conductors described above have a constant voltage. The number of diodes is not limited to one set, but may be multiple sets, and the diode is not strictly limited to constant voltage diodes, and any diode that can achieve the above-mentioned effect can be appropriately selected and used. .

Next, automatic control of the induction motor will be explained with reference to FIGS. 1, 2, and 19.

The terminals of the windings 22 and 23 applied to the first stator 24 and second stator 25 of the induction motor 1 are extended from inside the machine frame 14 and connected to three-phase commercial power sources a, b, and c via the switch 51. It is. Control value setting to set the speed, etc. of the induction motor 1 corresponding to the rotational speed of the load! ! ! 52 is connected to a control device 53 equipped with a memory circuit and a comparison/arithmetic circuit, and a speed detector 5 such as a tacho generator is installed on the rotor shaft 4 of the electric machine 1.
4, and a pulse motor 3 that rotationally controls the first stator 24.
5, the switch 51, and the air pipe to the ventilation port 4 of the bearing board 16.
An electric motor 55 that drives a blower 57 connected to 0...
and a temperature detector 56 that detects 8 degrees (inside the machine frame 14) are connected to the control device 53.

With the above configuration, the speed control value of the electric motor 1 and the first pulse control of the pulse motor 35 for each rotation angle of the first stator 24 are transmitted from the control value setting board 52 to the control device 53.
Enter. The output signal from the control device δ53 is sent to the switch 5.
1 to start the electric motor 1, the speed detector 54 detects the speed of the rotor 4, and the speed control value to which the rotation speed of the rotor 8 is input is transmitted to the control device 53 which communicates the detected value. If it is different from C), the rotation angle by the first stator 24 is calculated so that it becomes the speed control value, and the number of operating pulses of the pulse motor 35 is calculated, and the calculated value is sent to Il+control device 53. The output signal operates the pulse motor 35 to rotate the first stator 24 and control it to a desired rotational speed. In some cases, a signal for controlling the rotational speed of the load is automatically inputted via the control value platen 52. In this case, the rotational speed control value of the electric motor 1 is used to control the rotational speed of the load, without passing through the speed detector 54. The rotation speed is automatically controlled to the desired speed by the operation of the motor 35, resulting in efficient electric operation with unmanned operation! ! 11 can be used.

In addition, the temperature detection 1st shift 56 detects that the temperature inside the machine frame 14 has risen above the temperature value set in the control device 53, and an output signal that communicates the detected value to the control device 53 is sent to the electric CJ machine 55. is started, and the stator 1 rotor, conductors, diodes, resistance materials, etc. are cooled by the air blowing action. J5,
An air cooling device may be connected to the blower 57, and the blower 54 may be operated independently of the temperature detector 56.

Effects of the Invention As explained above, according to the present invention, by rotating the stator on the rotating side with respect to the stator fixed to the machine frame to change the phase of the rotating magnetic field, The speed of the rotor can be controlled to any desired speed.

In addition, by connecting each of the plurality of conductors installed in each of the rotor cores, and applying an arbitrary voltage to each of the plurality of conductors in the space of the rotor core that does not face the stator or in the non-magnetic core part. Since it is short-circuited through a connecting member that conducts electricity, the rotation of the stator on the rotating side is increased and the phase of the rotating magnetic field is significantly shifted in the low-speed region, improving efficiency and obtaining large torque. It can be used for power sources that frequently repeat starting, stopping, and speed change control, and has a remarkable effect.

[Brief explanation of drawings]

1 to 19 are illustrations of embodiments of the present invention, in which FIG. 1 is a side sectional view of the induction motor of the present invention, FIG. 2 is a side view showing the rotation mechanism of the stator, and FIG. Partial enlarged view of Figure 1, No. 4
The figure shows the relationship between rotor slip and active power, Figure 5 is an electrical τ-plane circuit diagram of the rotor, Figure 6 is an electrical equivalent circuit diagram seen from the stator side, and Figure 7 is a diagram of multiple circuits. Fig. 8 is a partially enlarged view showing another embodiment of the rotor, Fig. 9 is an electrical Circuit diagram, Fig. 10 is a diagram showing the relationship between speed and torque characteristics, Fig. 11 is a partially enlarged view showing another embodiment of the rotor, Fig. 12 is an electrical equivalent circuit diagram, and Fig. 13 is a diagram showing the phase angle. Fig. 14 is a partially enlarged view showing another embodiment of the rotor;
Fig. 5 is an electrical equivalent circuit diagram, Fig. 16 is a diagram showing the relationship between phase angle, torque phase angle, and 1 to torque characteristics, Fig. 17 is a partially enlarged view with the rotor as a winding type, and Fig. 18 is a FIG. 17 is a diagram showing the connections of each winding, and FIG. 19 is a block diagram showing automatic control of the induction motor.

Claims (6)

[Claims] (1) A plurality of stators with windings are arranged in parallel at arbitrary intervals, at least one of the plurality of stators is fixed to the machine frame, and at least one is attached to the rotor. a plurality of rotor cores arranged on an inner circumferential surface facing the plurality of stators and mounted on the rotor shaft; A plurality of conductors respectively installed in the cores are connected to form an integral rotor, and in a space between the plurality of rotor cores or a non-magnetic core portion that does not face the stator, the An induction motor characterized in that each of a plurality of conductors is short-circuited via a connecting member that conducts current when a given voltage is applied. (2) Claim No. (2), wherein the connecting material is a resistance material.
The induction motor described in item 1). (3) The induction motor according to claim (1), wherein the connecting member is at least one set of diodes connected in series with opposite polarities. (4) The induction motor according to claim (1), wherein the connecting member is formed by connecting in series at least one set of diodes connected in series with opposite polarities and a resistive material. (5) The induction motor according to claim (1), in which the connecting member is formed by arranging at least one set of diodes connected in series with opposite polarities and a resistive material. (6) The induction motor according to any one of claims (1) to (5), wherein the diode is a constant voltage diode.