JPH0223094A - Induction motor with a plurality of stator - Google Patents

Abstract

PURPOSE:To accelerate or decelerate a sufficient torque responsive to variation in a load by switching the connection of the windings of at least one of a plurality of stators to vary a phase difference. CONSTITUTION:The conductors of a plurality of rotor cores 2, 3 supported at an arbitrary interval to the same rotary shaft are connected to form an integral rotor. A plurality of stators 24, 25 are oppositely provided concentrically with the cores 2, 3 on its outer periphery. A switch circuit 81 is provided at one stator 24 to switch the connecting state of windings 22, 23. The state of a load 83 is detected by sensors 87, 88, the connection of the windings 23, 24 is switched in response to the detected result, and its phase difference is switched to one or both of 180 deg., 0 deg. and 120 deg., 60 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a multi-stator induction lightning VJ machine, and more particularly to a multi-stator induction lightning VJ machine having a single rotor, a plurality of stators and a voltage phase shifting device. The present invention also relates to a multi-stator induction motor in which the rotational speed of the rotor and the generated torque can be changed by (2) operating the voltage phase shift device.

[Prior art and its problems]

Conventionally, when starting a squirrel type 14 conductive motor that is commonly used, star-delta starting, reactor starting, starting compensator starting, etc. are known as means for controlling the starting current. Although the above means can control the starting current, it cannot improve the starting torque.

Furthermore, in wire-wound electric motors, although it is possible to improve the starting torque by changing the resistance value of the secondary resistor, it is necessary to use brushes and stop rings, making maintainability difficult.

To address the above problems, for example,
There is a technique disclosed in Japanese Patent No.-29005. This device consists of two sets of rotor cores installed coaxially, two sets of stators each having independent stator windings facing the rotor cores, and two sets of stators that straddle each of the rotor cores. A squirrel cage conductor that is installed in common and short-circuited at both ends via short-circuit rings, and a high-wire cage conductor that is short-circuited between the squirrel-cage conductors at the center of the squirrel-cage conductors between two sets of rotor cores. This is a twin core squirrel-cage type motor, which is equipped with a resistor, shifts the phase of each set of stator windings by 180 degrees during startup, and supplies power while matching the phases during operation after startup. By shifting the phases of the stator windings by 180 degrees during startup, the starting torque is adjusted to improve the starting characteristics, and during operation, the phases of the stator windings are matched to allow normal torque characteristic C operation. It is characterized by points. Therefore, although the effect of improving startability is recognized, when increasing or decreasing the rotational speed under load, it is necessary to ensure sufficient torque and reduce the amount of force required to automatically change the phase difference. It was not equipped with such a system, and its only purpose was to reduce the starting current and increase the starting torque. Also,
It was only possible to set and maintain the phase difference of 180° and Oo, and it was not compatible with a wide range of workpieces. Therefore, the starting torque is limited to a torque characteristic with a phase difference of 180°, and it is not possible to respond to a wide range of changes in load.

Note that the multiple stator induction motor of the present invention is a single-phase or three-phase induction motor.
It is used by connecting to a phase power source, etc., and the rotor can be of any type, such as parallel cage type, double cage type, deep groove cage type, special squirrel cage type, and single winding type. 2) The conductor used in the description of the present invention is a general term for the conductor installed in the squirrel cage rotor core and the winding wound around the wound rotor core. stators connected in parallel to the power supply, or multiple stators connected in series, and multiple stators connected in parallel.

Applying windings that form multiple types of pole numbers on the rotor, etc.
It can be selected and adopted arbitrarily.

[Means for solving problems]

As a means for achieving the above technical problem, the present invention includes:
A plurality of conductors installed in each of a plurality of rotor cores mounted on the same rotating shaft at arbitrary intervals are connected in a continuous manner to form an integral rotor, and the plurality of The plurality of conductors are short-circuited and connected between the rotor cores in the mouth 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 of the rotor cores, Positive pressure induced in the conductor portion of the rotor facing one stator in relation to at least one of the stators and the corresponding conductor portion of the rotor facing the other stator. In a motor equipped with a voltage phase shifter that creates a phase difference between the induced voltage and the induced voltage, the voltage phase shifter connected to a winding wound around one stator changes the phase difference by 180 degrees.
°, 0°, any one of 120° and 60°
The solution is to use an automatic phase switching device that can switch between one or both.

[For production]

The present invention provides an automatic phase difference switching device for a winding wound around at least one stator among a plurality of stators, and the phase difference is 180', 120'', 0'' or 180'.
0', 60", O°al or l 80°, 120",
60", O', and by short-circuiting the conductors between the rotor cores with a resistive material2), the phase difference is increased at startup to ensure high torque, and the phase difference gradually increases. Depending on the characteristics of the load, the speed can be increased by decreasing the phase difference to increase the speed under load, and the phase difference can be gradually increased from a small state to a large state to decelerate or stop the phase difference. Smooth increase/deceleration is possible.

In addition, the phase difference at the time of starting can be set not only to 18° but also to other phase differences in b stages, allowing better response to the characteristics of the load.

Furthermore, there are various types of loads that are connected to and driven by the electric search2), and even for the same load, the amount of torque required at starting may differ, so depending on the type and condition of the load, By selecting the phase difference and appropriately setting the timing of switching the phase difference by the automatic phase switching device, it is possible to smoothly increase or decelerate the load.

〔Example〕

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

First, the configuration will be explained based on FIGS. 1 to 3.

Reference numeral 1 denotes an induction motor 2), and the induction motor 1 is constructed as follows. Rotor cores 2 and 3 made of iron cores are mounted on the rotor FIl 14 with an arbitrary interval between them, and 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 core 2.3 is connected in a continuous manner to form an integral rotor 8, and the plurality of conductors 5... installed in the rotor core 2.3 are connected in a continuous manner. Both ends of ・are connected to a short circuit ring 6°7. In addition, a plurality of ventilation cylinders 12 . A plurality of ventilation holes 13... are bored through the. The rotor 8 has a non-magnetic core 9 between the rotor cores 2 and 3, and a nichrome wire or carbon is used as a connecting material that conducts electricity when a current with an arbitrary vector difference flows through each of the plurality of conductors 5. The mixed steel 1 is short-circuited through the resistive material r such as conductive ceramic. Cylindrical machine frame 14
Bearing discs 15 and 16 provided on both sides of the rotor 8 are integrally assembled with bolts 17, and cooling impellers 19 and 20 are installed on both sides of the rotor 8.
is mounted, and both ends of the rotor shaft 4 are supported by bearings 21 and 21 fitted in bearing discs 15 and 16, so that the rotor 4 can freely rotate.

As mentioned above, configuring the space between the rotor cores 2 and 3 with a non-magnetic material improves torque characteristics by reducing leakage reactance and improves efficiency. It also contributes to improving strength.

A first stator 24 and a second stator 25, each having a winding 22.23 on its outer side facing the rotor core 2.3, and a second stator 25 are arranged side by side on the frame 14. 39 is an exhaust hole, 40 is a bearing plate 15.16
This is a ventilation hole with multiple holes drilled in it.

As the rotor 8 rotates 2), outside air is sucked into the machine frame 14 by the ventilation holes 40 bored in the bearing discs 15 and 16. 19.20
According to the 1st. The second stator 24°25 and the windings 22 and 23 are ventilated and cooled, and the second stator 24°25 and the windings 22 and 23 are cooled. The rotor cores 2 and 3 are affected by the wind flowing through the I-body 12 and the ventilation holes 13.
, conductor 5 . . . , resistor material r .

Next, the connection of the windings 22 and 23 wound around the first stator and the second stator will be explained based on FIGS. 4 to 7 (details will be described later).

At least the following four wiring methods can be considered to realize the present invention. These are so-called series Δ connections, series Y connections, parallel Δ connections, and parallel Y connections. Wires are connected to the terminals of each winding like △ and Y, and the connections are equipped with a group of changeover switches (S+, S+', S
2°S2', S3. Sl', S4. S4', S5
°S5', Sa, Se') are present (Figs. 4 to 7). By switching this switch 2), the phase of the voltage induced in the rotor conductor facing the first stator and the second stator, respectively, is changed to 0°, 60', 12
This results in a difference of 0° and 180'. This forms a voltage phase shifting device.

This voltage phase shifter is also provided with a switch circuit 71 made up of the switch group, and further includes an automatic phase change device 79 (Fig. 1) that switches this switch circuit 71 with a sequence circuit 74 made up of a timer, and An automatic phase switching device 89 (FIG. 2) is equipped with speed detectors and other sensors (87, 88) for detecting and monitoring status and speed, and switches the switch circuit via a sequence circuit 84 after a predetermined management system 86. Equipped with

The operation of the above configuration will be explained below.

When the windings 22 of the first stator 24 are energized from a commercial three-phase power supply, a rotating magnetic field is generated in the stator 24.25, voltage is induced in the rotor 8, and current is generated in the conductors 5 of the rotor 8. The flow causes the rotor 8 to rotate.

When the phase difference of the voltage of the second stator 25 with respect to the first stator 24 is set to zero, it is 1, and there is no phase shift in the magnetic flux of the rotating magnetic field generated in each stator 24, 25, the details of which will be described later. Since no current flows through the resistance material r... which forms the connection material, it has the same torque characteristics as a general induction motor.

What is shown in FIG. 8 is the slip S of the rotor 8 and the rotor input when the resistance material r... that short-circuits the plurality of conductors 5... is not installed in the non-magnetic core 9 portion. This shows the relationship with the active power P. When the voltage phase is 0=0°, the active power P is maximum2), and is smaller at the angle of 0°<θ<180°. Here conductor 5...
Let R and L be the resistance and inductance of
ωL) appears at the end.

Since the active power P is proportional to the driving torque of the induction motor 1, the voltage induced in the rotor 8 can be adjusted by changing the changeover switch, and the speed of the rotor can be controlled steplessly under load conditions. can.

Next, let R1 and R2 be the respective resistances from the short-circuit rings 6 and 7 of the conductors 5 of the rotor 8 to the connecting material, 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 ... is r, the electrical equivalent circuit of the rotor 8 is as shown in Fig. 9.
), symbols I+, I2, and 13 indicate the current flowing through each branch.

Next, when converting the circuit shown in Fig. 9 into a circuit as seen from both stators 24 and 25 side, it becomes as shown in Fig. 102), RI
=R2, LI=L2 and when θ=0°, l3=II-
12=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, θ=0
The ° sharpener will have the same torque characteristics as a conventional induction motor.

Next, when R+ = R2, L+ = L2 and θ = 180°, I+ = -12, "I: + = I + -12 = 211
2) In a conventional induction motor, if the resistance of the rotor conductor is RI=R2=R, the result is similar to that of increasing R to R+2r.

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

Since the windings 22 and 23 are connected in series, the windings 22 and 23 are connected in series.
A current flows between the windings 22 and 23 when input from a commercial 3-phase power source, but if there is a difference in the resistance of each of the windings 22 and 23 or a difference in the capacitance of both stators 24 and 25. However, independently of that, each winding 22.23
The magnitude of the current flowing through the conductor 5 of the rotor 8 is equal, therefore, from each of the first stator 24 and the second stator 25 to the conductor 5 of the rotor 8
. . . the magnitude of the current induced and flowing is equal, and the first stator 24 and the second stator 2 of the voltage phase shifter 38
5 of the rotor 8 from each of the stators 24 and 25, depending on the phase difference that occurs in the magnetic flux of the rotating magnetic field.
The force that causes the magnitude of the current flowing through the conductors 5 to become equal, and the vector difference current caused by the phase difference between the voltages between both stators 24 and 25 flow through the plurality of conductors 5 and 5.
Due to the synergistic effect of the force that inevitably flows through the resistance material r..., which serves as a connecting member for each of the...2), the slip and torque characteristics shown in Fig. 11 are obtained. It improves efficiency and generates large torque in each speed range, and even when a load is connected, it is easy to start in each speed range, and it adapts to the start characteristics of the load to achieve smooth start. You can use it as you like, such as starting with high output or starting with high output.
Optimal support for power sources that frequently stop. As mentioned above, the speed of the rotor 8 can be changed arbitrarily by controlling the phase shift and increasing or decreasing the current flowing through the conductors 5 of the rotor 8. I can do it.

Note that the first stator 24 has windings 22 and 23 connected in series.
and the second stator 25 to the conductor 5 of the rotor 8, respectively.
・For the magnitude of the current flowing in ・, multiple conductors 5...
The ratio of the current that flows in a short circuit through the resistive material r... is determined by the value of Pθ (P - number of pole pairs, θ - phase angle), regardless of the resistance value and slip of the resistive material "..." (The above ratio is the maximum for Pθ-π and becomes zero at Pθ=O.) If Pθ is constant, the same slip as when the secondary insertion resistance of a general wound induction motor is constant. Regarding the torque characteristics 2), when Pθ becomes small, the conductor 5 of the rotor 8...
Since the ratio of current flowing through the motor is small2), reducing Pθ has the same effect as reducing the secondary insertion resistance of a general wound induction motor. When the rated current flows through both stators 24 and 25, the phase difference θ
Even if you change it arbitrarily, depending on the selection of the slip value and the design of the resistance value of the connecting member 2), the constant 18 current and rated torque characteristics of the maximum speed can be applied almost simultaneously in each speed range. .

Also, 1st. Even if the windings 22 and 23 of the second stator 24 and 25 are connected in series, if a connecting material is provided between the conductors 5 and there is no short circuit, the rotor will be connected from one stator to the other. Almost no voltage is induced in the conductor 5...2), and the efficiency is lower than that of the one in which the windings 22 and 23 of both stators 24 and 25 are connected in parallel to the power supply. Become.

In contrast to the above, the windings 2 of the first stator 24 and the second stator 25
2.23 are connected in parallel to a commercial three-phase power supply, the windings 22.23 of the first stator 24 and the second stator 25.
The voltages input to the stators 23 and 23 are the same, and the voltages induced from each of the stators 24 and 25 to the conductors 5 of the rotor 8 are the same, but the phases of the voltages differ by Pθ2). The current that flows through the resistive material r, which serves as a connecting material between..., is (1/2) Material r...
The current is approximately proportional to the resistance value of however,
In the conductor 5 of the rotor 8, in addition to the current flowing through the resistive material r... Almost proportional currents flow in a superimposed manner. (The above sum voltage is maximum when Pθ=π is zero and Pθ=02).The impedance of the rotor conductor is composed of the resistance of the conductor and the secondary leakage reactance, respectively, and therefore varies depending on the slippage.) Therefore, the rotor 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 in No. 8 varies depending on the slip and resistance value even if Pθ is constant. 2) The slip and torque characteristics when Pθ is constant are the same as those when the secondary insertion resistance of a general wound induction motor is constant, and those when the primary voltage of a general induction motor is controlled. As shown in FIG. 12, which is a mixture of characteristics 1 and 2), this characteristic is Second stator 24.
Compared to the characteristics when the valley lines 22 and 23 of 25 are connected in series, in the case of a load with constant torque characteristics that is much smaller than the rated torque, the speed control range is narrow.
Depending on the resistance value of the resistance material 2), for example, a fan,
It can be used for loads such as pumps that require a reduced one-herc drive or for loads that require a small shift range.

Next, with reference to FIGS. 4 to 7 and FIGS. 13 to 16, description will be given of the foil wires of the windings that are applied to each of the first stator 24 and the second stator 25 to generate a plurality of phase differences.

Generally, in symmetrical three-phase AC, the instantaneous value of electromotive force e
a, e b, e c are as follows.

ea −Em 3inωt, eb =Em 5in(ω
t -2π/3) ea = Em 5in (ωt -4yr/3) This E
The vector diagram of a, Eb, and Fc is as shown in Figure 182)
, each electromotive force has a phase difference of 2π/3, but for such a three-phase AC, that is, for a commercial three-phase power supply, the windings of the first stator and second stator have a phase difference of 2π/3. By making one of the connections shown in Figure 7 and changing each connection from 1) to (4), 2) the relative 0°, 60”,
This results in a phase difference of 120° and 180°.

For example, if we look at the connection of picture column Y in Figure 14, the power supply U,
V, W to winding 23, terminals UF, VF.

WF, and the other terminals XF, YF of the winding 23,
ZF to terminal UM of winding 22, respectively.

Connect to VM, WM, and the other terminal XM of the winding 22,
YM and ZM are shorted (connection (1)).

At that time, no phase difference occurs in the windings 22 and 23. However, terminals UM, VM, WM and XM, YM, Z of winding 22
When the terminals of M are connected as shown in (2), the vector diagram becomes θ=
The connection (1
), it is equivalent to a phase difference of π/3.

Similarly, by switching the connections (3) and (4), the phase difference between the voltages induced in the rotor conductors facing the winding 23 and the winding 22, that is, the first stator and the second stator, is It changes. This connection switching is shown in Figures 4 to 7 above.
This is done by switching the switch group shown in the figure. Here, regarding the other connections, that is, Figures 14, 15, and 16, the voltage vector diagram when changing the connection from (1) to (4) is almost the same, so the explanation will be omitted. .

Table 1 below shows the open/close states of the switches for producing the respective phase differences in each connection method.

Next, a switch circuit made up of the above switch group will be explained.

17(1) to (4) are switch circuits corresponding to direct Δ-type connection, series Y-type connection, parallel Δ-type connection, and parallel Y-type connection, respectively.

[S1] to [S4'] of the switch circuit used in the series Δ type connection shown in FIG. 17(1) are S+ shown in FIG.
S'+, 82. S2-, S1. S3-. 84. S4
- A magnet, such as a magnetic switch, or something similar.

Terminals ■ to ■ are terminals that are connected and supplied with power by rotating the rotary switch 60, where ■ indicates a phase difference of 0°, ■ indicates a phase difference of 6°, ■ indicates a phase difference of 120°, and ■
correspond to a phase difference of 180° and can be freely selected. [S1] to [S] in Figure 17 (2) to (4) of the pond.
24'] correspond to 81 to 824' in FIGS. 5 to 6, respectively, and are means for opening and closing the switches 81 to 824'.

Furthermore, as shown in FIGS. 17(2) to (4), there are some rotary switches 61 in which two rotary switches 61 are interlocked. In addition, there are many other switches having the same function as the rotary switch 61, and [811 to 824'] are not limited to the present embodiment. The same applies to the entire switch circuit.

Next, the electric motor is variable speed controlled using the switch circuit 2), and two examples of variable speed control will be shown below.

The first embodiment is the timer control method shown in FIG. 19(1). , the switch circuit 71 and the sequence circuit 74 controlled by a timer form an automatic phase switching device 79, and the variable speed induction electric motor F! 572 (motor in the figure, hereinafter referred to as "motor"). The automatic phase switching device 79 is connected to the start/stop circuit 75 (2).
, starts and stops the motor.

When the load resistance torque, moment of inertia, motor capacity, or acceleration/deceleration speed is determined, the automatic phase switching device 79 uses a timer to determine the rotation time for each phase difference (2), and starts and Acceleration and deceleration can be performed automatically by switching the switch circuit using a sequence circuit in response to a stop signal.

Next, a second embodiment is shown in FIG. 19 (S). It is a fully automatic control system. First, an automatic phase switching device 89 is formed by a speed detection sequence circuit 84 and a switch circuit 81 operated by the sequence circuit. do.

The speed detection sequence circuit 84 includes a speed detection sensor 87 that detects the speed of the load and a start/stop circuit 85.
is connected to the start/stop circuit 85, and further connected to the start/stop circuit 85 are a monitoring sensor 88 for detecting the state of the load and a management system 86.

The management system 86 captures information on the load using a monitoring sensor 88, manages whether work is being carried out efficiently, and depending on the status, sends a command to the start/stop circuit 85 (2), so that the start/stop circuit 85 automatically starts. An acceleration or deceleration command is sent to the phase switching device 89.

In addition, the speed detection sensor has a speed detection sequence circuit 8.
It fulfills the feedback function to 4.

This is based on the information from the management system 86, detects load fluctuations with the speed sensor 87, and feeds that information back to the sequence circuit 84 to automatically accelerate or decelerate according to the load fluctuations. 1.

(Effects of the Invention) As explained above, according to the present invention, each of the conductors attached to a plurality of rotor cores is short-circuited via a resistive material, and at least one of the plurality of stators is In connection with this, by installing an automatic phase switching device on the wound windings and adding 60° to 120° to the phase difference setting2), it is possible to reduce the starting current and increase the starting torque, unlike conventional methods. Compared to those intended for this purpose, it is possible to accelerate and decelerate with sufficient torque to match changes in load, and the starting torque can also be changed depending on the load. Further, since the shock caused by changing the phase difference is reduced and the automatic phase switching device described above can be provided, it is possible to adapt to a wide range of loads.

[Brief explanation of the drawing]

Figures 1 to 19 are illustrations of embodiments of the present invention.
Figure 2 is a side sectional view of the induction motor, Figure 3 is a cross sectional view, Figures 4 to 7 are connection diagrams of stator windings, and Figure 8 is a diagram showing rotor slip and effective Figure 9 shows the electric power relationship. Figure 9 is an electrical equivalent circuit diagram of the rotor. Figure 10 is an electrical equivalent circuit diagram seen from the stator side. Figure 11 shows how each of the multiple conductors is connected using a resistive material. A diagram showing the relationship between speed and torque when short-circuited and the windings wound around the stator are connected in series,
Figure 12 is a diagram showing the relationship between speed and slip when each of the stator windings is connected to a power source in parallel, and Figures 13 to 16 show a wiring method that creates multiple phase differences in the stator. Figure 17 is a diagram showing a switch circuit for producing multiple phase differences in the stator, Figure 18 is a vector diagram showing the instantaneous value of the electromotive force of three-phase symmetrical alternating current, and Figure 19 is a diagram showing a switch circuit for producing multiple phase differences in the stator. FIG. 2 is a block diagram showing speed control of a guided lightning F71 aircraft. 1... Induction motor, 2, 3... Rotor core, 4...
・Rotor shaft, 5... Conductor, 6, 7... Short circuit ring, 8.
...Rotor, 9...Nonmagnetic core, 10.11...Side part, 12...Ventilation barrel, 13...Vent hole, 14...
Machine frame, 15° 16...Bearing plate, 17...Bolt, 1
9.20... Cooling impeller, 21... Bearing, 22.2
3... Winding wire, 24... First stator, 25... Second
Stator, 39... Ventilation port, 40... Ventilation hole, 69.
61... Selector switch, 70... Power supply, 71...
Switch circuit, 72... Induction motor, 73... Load, 74... Timer sequence circuit, 75... Start/stop circuit, 79... Automatic phase switching device, 8
1... Switch circuit, 82... Induction motor, 83.
...Load, 84...Speed detection sequence circuit, 85.
...Start/stop circuit, 86...Management system, 87...Speed detection sensor, 88...Monitoring sensor 89...Automatic phase switching device.

Claims (3)

[Claims] (1) A plurality of conductors installed in each of a plurality of rotor cores attached to the same rotating shaft at arbitrary intervals are connected in a continuous manner to form an integrated rotor. death,
The plurality of conductors are short-circuited and connected between the plurality of 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. and, in relation to at least one stator among the plurality of stators, a voltage induced in a conductor portion of a rotor facing one stator and a conductor of a rotor facing the other stator. In a motor provided with a voltage phase shifter that generates a phase difference between a voltage induced in a part and a voltage induced in a part, the voltage phase shifter connected to a winding wound around one stator changes the phase difference by 180 degrees. °, along with 0°, among 120° and 60°,
A variable speed induction motor characterized by an automatic phase switching device capable of switching to either one or both. (2) The multiple stator induction motor according to claim (1), wherein the automatic phase switching device comprises a sequence circuit comprising a timer and a switch circuit. (3) The automatic phase switching device is comprised of a speed detector and a switch circuit provided directly or indirectly in relation to the rotating shaft of the electric motor or the load driven by the electric motor. ) described multiple stator induction motor.