JP2981818B2 - Induction motor control circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control circuit for an induction motor, and more particularly to a control circuit for performing braking by DC braking.

[0002]

2. Description of the Related Art FIG. 6 shows a conventional control circuit for a capacitor-type single-phase induction motor. This control circuit includes a pair of triacs 100 and 102 for forward / reverse control, a thyristor 104 for braking control, and diodes 110 and 112.

[0003] First and second AC power
Are connected in series with the first and second primary windings 108A, 108B of the induction motor 108, respectively, and the thyristor 104 is connected to both primary windings 108A, 108B.
A and 108B are connected in series via diodes 110 and 112, respectively. The thyristor 104 and the diodes 110 and 112 are connected in the same direction, that is, with their respective anodes facing the primary windings 108A and 108B.

The primary windings 108A and 108B are connected in parallel with each other, and each terminal on the opposite side to each terminal commonly connected to one terminal of the AC power supply 106, that is, each terminal on the triac 100 and 102 side is connected. Capacitor 1 between
14 are connected. The two primary windings 108A and 108B are arranged on the stator of the induction motor 108 at right angles to each other.

[0005] First and second triacs 100, 1
02 is on / off controlled by a forward rotation control signal dr + and a reverse rotation control signal dr-, respectively. When the first triac 100 is turned on while the second triac 102 is off, the first primary winding 108A directly connected to the first triac 100 operates as a main winding and is connected via the capacitor 114. Second primary winding 108B
Operate as auxiliary windings, and both primary windings 108A, 108A
The rotor of the induction motor 108 rotates in the positive direction due to the positive rotating magnetic field generated by the phase difference between the currents flowing through B.

When the first triac 100 is off,
When the second triac 102 turns on, the second primary winding 108B directly connected to the second triac 102
Operates as the main winding, and the triac 102
Primary winding 108A, which is connected to the primary winding 108 via a capacitor 114, operates as an auxiliary winding.
The rotor rotates in the opposite direction due to the rotating magnetic field in the opposite direction generated by the phase difference between the currents flowing through B and 108A.

To apply braking, both the first and second triacs 100 and 102 are turned off, and then the thyristor 104 is turned on by the braking control signal br. Then, the thyristor 104 and the diode 11
Current flows through both primary windings 108A and 108B simultaneously only during a half cycle in which a forward voltage is applied to 0 and 112. In this way, DC flows through the primary winding every half cycle, and the magnetic flux of the static magnetic field generated by the DC is cut off by the secondary winding on the rotor side, so that an electromotive force is generated in the secondary circuit. The next current flows. Since this secondary current generates a force that hinders relative movement with the magnetic field, the rotor is braked.

[0008]

In the above-described conventional induction motor control circuit, a large DC current (about four times the current during operation) flows through both primary windings 108A and 108B of the induction motor 108 during braking. This large current is
Because it also flows through thyristor 104 through 0,112,
The thyristor 104 and the diodes 110 and 112 have to be constituted by large-capacity rectifying elements, so that the circuit has become large and the device price has been high.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and eliminates the need for a special large-capacity rectifying element for flowing a DC current during braking, thereby reducing the size and cost of an induction motor. It is an object of the present invention to provide a control circuit.

[0010]

To achieve the above object, according to an aspect of the control circuit of the induction motor of the present invention, different from the first phases
First and second primary windings and the first and second primary windings
A capacitor connected between one end of each of the wires and
Control circuit for controlling the operation of induction motors with
And the first and second primary windings with respect to an AC power supply.
First and second photos respectively connected in series to a line
Triac and union with the first photo triac
Now, a first photocoupler is formed, and light is emitted from the first photocoupler.
Light emitting element for turning on photo triac
And the second phototriac in combination with the second
Forming a photocoupler and emitting light to the second phototransistor;
A second light-emitting element for turning on the earac;
The second light emitting element emits light to perform a forward rotation operation of the motor.
Without causing the first light emitting element to emit light continuously.
To turn on the first phototriac continuously.
In order to perform the reverse operation of the induction motor,
Continue the second light emitting element without causing the light element to emit light
To continuously emit the second phototriac
An operation control circuit for turning on the power supply and connecting to the AC power supply
And one pole of an AC voltage supplied from the AC power supply.
Light-emitting element that emits light by conducting only in a half cycle of the light
And a third photocoupler in combination with the third light emitting element.
The third light-emitting element emits light when the third light-emitting element emits light.
Including a photoelectric conversion element that applies a brake to the induction motor.
Therefore, light is emitted every half cycle of the third light emitting element.
In synchronization with the timing, one half of the polarity of the AC voltage
The first and second light emitting elements are simultaneously emitted only in the cycle.
And illuminate the first and second phototriacs.
And a braking control circuit that is turned on at times.
Was. More preferably, in addition to the above configuration,
Connected to a third phototriac in series with the
Primary winding and work on the rotor of the induction motor.
A non-load operation type electromagnetic brake dynamically coupled to the electromagnetic brake;
Fourth photocoupler in combination with a phototriac
And emits light to turn on the third phototriac.
A fourth light emitting element for turning on the induction motor and the induction motor
Alternatively, during the reverse rotation, the fourth light-emitting element is
Turn on the third phototriac and turn on the electromagnetic
When the brake is applied to the induction motor and the induction motor is
The fourth light emitting element is turned off and the third photo
Turn off the triac and de-energize the electromagnetic brake
And an electromagnetic brake control circuit
Was.

[0011]

In the control circuit of the present invention, when performing the forward rotation operation
Is the first light emitting element in the first photocoupler continuously.
The first phototriac is energized and the first
And the phase difference between the currents flowing through the second primary winding
The rotation of the induction motor is
The trochanter rotates in the forward direction. When performing reverse operation
Is the second light emitting element in the second photocoupler continuously.
The second phototriac is energized and the first
And the phase difference between the currents flowing through the second primary winding
The rotation of the induction motor is
The trochanter rotates in the opposite direction. When braking, the braking system
By the operation of the control circuit, the third
The timing at which light is emitted every half cycle
Detected through the electrical conversion element and synchronized with that timing
Only the first half cycle of one polarity of the AC power supply voltage.
And the second photocoupler are simultaneously activated to activate the first and second photocouplers.
The second phototriac is energized at the same time. 1st, 1st
In the second and third photocouplers, supply of the AC power supply voltage is performed.
First and second phototriacs and third
Control circuit is electrically isolated from the light emitting element
Therefore, a small-capacity element can be used for the control system circuit,
Significant size reduction and cost reduction of the control board can be realized.
You.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows the configuration of a control circuit for a capacitor-type single-phase induction motor according to a first embodiment of the present invention.

This control circuit has a pair of phototriac output type photocouplers 10 and 12 for forward / reverse control, and one phototransistor output type photocoupler 14 and a pair of diodes 16 and 18.

An AC power supply 20 is connected to a photocoupler 10
The phototriac 10B is connected in series with the first primary winding 22A of the capacitor type single-phase induction motor 22, and the phototriac 12B of the photocoupler 12 is connected in series with the second primary winding 22B of the induction motor 22. ing. The two primary windings 22A and 22B are connected in parallel with each other, and each winding terminal on the opposite side to each winding terminal commonly connected to one terminal of the AC power supply 20, that is, each winding terminal on the phototriac 10B and 12B side. Capacitor 2 between
4 are connected. The two primary windings 22A and 22B are arranged on the stator of the induction motor 22 at right angles to each other. The AC power supply 20 supplies a single-phase AC voltage having a frequency of 50 Hz and an effective voltage of 100 V, for example.

In the photocoupler 10, the input side light emitting diode 10A has an anode terminal connected to, for example, a 12 V DC power supply Vcc via a resistor 26, a cathode terminal connected to an output terminal of an inverting circuit 28, and a diode 16A. Is connected to the collector terminal of the phototransistor 14B of the photocoupler 14.

In the photocoupler 12, light emission on the input side
The diode 12A has an anode terminal connected to a DC power supply Vcc of, for example, 12 V via a resistor 26, a cathode terminal connected to an output terminal of an inversion circuit 32, and a diode 18 connected to a collector terminal of a phototransistor 14B. ing.

In the photocoupler 14, the emitter terminal of the output phototransistor 14B is connected to the output terminal of the inverting circuit 34. Light-emitting diode 1 on the input side
4A is connected to the AC power supply 20 via the resistor 36. A protection diode 38 is connected in parallel with the light emitting diode 14A in the opposite direction.

The inverting circuits 28, 32, and 34 respectively provide a binary level normal rotation control signal DR +, a reverse rotation control signal DR-, and a braking control signal B from an operation sequencer circuit (not shown).
R is input. Next, the operation of the control circuit will be described.

When the induction motor 22 is rotated forward, the forward rotation control signal DR + is set to the H level, and the other control signals DR-,
BR is set to L level. Then, the forward rotation control signal DR
Since + is at the H level, the output of the inverting circuit 28 becomes L,
In the photocoupler 10, the light emitting diode 10A is turned on to emit light, and the light turns on the phototriac 10B. On the other hand, since the reverse control signal DR- is at the L level, the output of the inverting circuit 32 is H, and in the photocoupler 12, the light emitting diode 12A does not emit light and the phototriac 10B is off. Also in the photocoupler 14, since the braking control signal BR is at L level, the output of the inverting circuit 32 is H
Thus, the output-side phototransistor 14B does not conduct even when receiving light from the light-emitting diode 14A, so that no current flows through the diodes 16 and 18.

In this case, in the induction motor 22, the first primary winding 22A directly connected to the phototriac 10B operates as a main winding, and the phototriac 1
0B via a capacitor 24 operates as an auxiliary winding, and both primary windings 22A, 22A,
The rotor rotates in the positive direction due to the positive rotating magnetic field generated by the phase difference between the currents flowing through the respective coils 22B.

To reverse the induction motor 22, the reverse control signal DR- is set to the H level, and the other control signals DR +,
BR is set to L level. This time, the photocoupler 10 is turned off and the photocoupler 12 is turned on. In the induction motor 22, the second primary winding 22B directly connected to the phototriac 12B operates as a main winding, and 24 connected through the first primary winding 22A
Operate as auxiliary windings, and the rotor rotates in the opposite direction due to the rotating magnetic field in the opposite direction generated by the phase difference between the currents flowing through the primary windings 22B and 22A.

When braking the induction motor 22, the braking control signal BR is set to H level, and the other control signals DR +,
DR- is set to L level. In this case, the photocoupler 1
0 and 12 are not turned on by the forward control signal DR + and the reverse control signal DR-, respectively. However, since the braking control signal BR is at the H level, the output voltage of the inverting circuit 34 is at the L level, and the phototransistor 14B of the photocoupler 14 becomes conductive.

Therefore, when the light emitting diode 14A emits light, that is, during each half cycle in which the AC voltage from the AC power supply 20 is applied to the light emitting diode 14A in the forward direction, the phototransistor 14B is turned on, whereby the photocoupler is turned on. 10 and 12 are simultaneously turned on. That is,
When the phototransistor 14B conducts, the current from the power supply voltage terminal Vcc is applied to the phototransistor 1 via the resistors 26 and 30, the light emitting diodes 10A and 12A of the photocouplers 10 and 12, and the coupling diodes 16 and 18, respectively.
4B flows as a collector current of 4B, and both photocouplers 10,
In 12, the light emitting diodes 10A and 12A emit light, and in response to the light, the phototriacs 10B and 12B
Is turned on.

As described above, during each half cycle of one polarity in which the light emitting diode 14A emits light, both phototriacs 10B and 12B are turned on at the same time, whereby the two primary windings 22A and 22B of the induction motor 22 are connected. Current flows at the same time. Then, during each half cycle of the other polarity in which the light emitting diode 14A is not turned on, the phototransistor 14B does not conduct, and both the phototriacs 10B and 12B are turned off. In addition, during each half cycle of the other polarity in which the light emitting diode 14A is turned off, a forward voltage is applied to the diode 38 to turn it on, so that the light emitting diode 14A is protected from excessive reverse bias. I have.

In this way, in the induction motor 22, a half-wave current every half cycle flows as a DC current in the primary windings 22A and 22B, thereby generating a static magnetic field.
An electromotive force is generated in the secondary winding on the rotor side that cuts off the magnetic flux of the static magnetic field, and the rotor is braked by electromagnetic interaction between the secondary current and the magnetic field.

As described above, in the control circuit of the induction motor in this embodiment, when the operation (forward / reverse rotation) operation is performed, the triacs (10, 12) are energized in half cycles of both polarities, and the induction motor 22 is turned on. Primary winding (22A, 22
An alternating current for generating a rotating magnetic field is passed through B), and when braking is performed, the triacs (10, 12) are energized only in a half cycle of one polarity so that the primary winding (2) of the induction motor 22 is turned on.
2A and 22B), a direct current for causing a direct current braking is supplied.

Thus, the primary windings (20A, 20B)
Operation control triac (10,
12) During braking, only one half cycle is energized, so that half-wave currents are supplied to the primary windings (20A, 20B) every other half cycle as direct current. The provided large-capacity rectifier such as the thyristor (104) and the diodes (110, 112) is unnecessary in the control circuit of the present embodiment.
Further, a control unit (light electric circuit unit) for switching control of the triacs (10, 12) is provided with photocouplers 10, 12, 1.
4, the control unit can use a small-capacitance element (particularly, diodes 16 and 18). Therefore, the size of the control board can be significantly reduced, and the cost can be significantly reduced.

FIG. 2 shows the configuration of a control circuit for a capacitor-type single-phase induction motor according to a second embodiment. In the figure, parts common to the first embodiment (FIG. 1) are denoted by the same reference numerals.

The control circuit according to the first embodiment also controls the electromagnetic brake attached to the induction motor 22 in addition to the control circuit according to the first embodiment. The BR is automatically generated to perform DC braking.

In FIG. 2, a phototriac 40B of a photocoupler 40 is connected in series with a primary winding 42A of a non-excitation operation type electromagnetic brake 42 to an AC power supply 20. Electromagnetic brake 42 is derived is operatively coupled to a rotating element of the motor 22, it releases the mechanical brake while primary winding 42A to the exciting current flows in the electromagnetic force (disabled), the exciting current flows When it is gone, a mechanical brake is operated (enabled) to brake the rotor of the induction motor 22.

Light emitting diode 40A of photocoupler 40
Has an anode terminal connected to the terminal of the power supply voltage Vcc via the resistor 44, and a cathode terminal connected to the output terminal of the inverting circuit 46. The input terminals of the inverting circuit 46 are commonly connected to the cathode terminals of the diodes 48 and 50, and the anode terminals of the diodes 48 and 50 are connected to the inverting circuit 2 respectively.
8, 32 input terminals. An output terminal of the inverting circuit 46 is connected to an input terminal of the inverting circuit 34 via a time constant circuit including a capacitor 52 and a resistor 54. A diode 56 connected in parallel with the resistor 54 with the cathode terminal directed to the input terminal of the inverting circuit 34 is a diode for clamping.

In such a configuration, the diode 48,
A circuit for controlling the operation of the electromagnetic brake 42 is constituted by the 50, the inverting circuit 46 and the photocoupler 40. The diodes 48 and 50, the inverting circuit 46 and the time constant circuit (5
2, 54) constitute a circuit for generating the braking control signal BR.

Next, the operation of this embodiment will be described with reference to the timing chart of FIG.

While the normal rotation control signal DR + is maintained at the H level, as described above, the phototriac 10B of the photocoupler 10 is in the ON state, and the induction motor 22 rotates in the forward direction. Is going. During this time, the output voltage of the inverting circuit 46 is at the L level, and the photo coupler 40 for electromagnetic brake control is turned on, that is, the light emitting diode 4
0A emits light and the phototriac 40B is in the ON state, an exciting current flows through the primary winding 42A of the no-load operation type electromagnetic brake 42, and the brake on the induction motor 22 is stopped. The input voltage of the inverting circuit 34 is at the L level, the output voltage is at the H level, and the photocoupler 14 for braking control is in the off state.

When the normal rotation control signal DR + is set to L level at time t0, for example, to stop the rotation of the induction motor 22, the output voltage of the inversion circuit 46 is inverted to H level.
Thus, the photo coupler 40 for controlling the electromagnetic brake
Is turned off, the phototriac 40B is cut off, the exciting current stops flowing through the primary winding 42A of the electromagnetic brake 42, and the rotor of the induction motor 22 is mechanically braked by the electromagnetic brake 42.

On the other hand, when the output voltage of the inverting circuit 46 becomes H level, the input voltage of the inverting circuit 34 also rises to H level via the capacitor 52, and the output voltage of the inverting circuit 34 falls to L level (FIG. 3). (C), (D)). And
The output voltage BR- maintains the L level state until the input voltage of the inverting circuit 34 decreases exponentially and reaches the threshold value Vth (time t1) by the operation of the time constant circuits (52, 54). During this period TO (t0 to t1), the photocoupler 14 for braking control is turned on, and the same operation as that of the first embodiment is performed, as shown in FIGS. 3 (E) and 3 (F). When the triacs 10B and 12B conduct simultaneously in each half cycle of one polarity, half-wave DC flows through both primary windings 22A and 22B of the induction motor 22, and DC braking is applied.

As described above, when the forward rotation control signal DR + is turned off, the external electromagnetic brake 42 is automatically activated, and at the same time, the direct current braking is applied in the induction motor 22, so that the induction motor 22 is stopped instantaneously. It has become. Note that FIG.
Is the case where the forward rotation operation is stopped, but the same braking operation is performed when the reverse rotation operation is stopped.

FIG. 4 shows an example in which the induction motor control circuit according to the second embodiment is applied to an atmosphere shutter device of a cleaning system in a semiconductor manufacturing process.

In this type of cleaning system, various cleaning processing tanks are arranged in a line, and the transfer robot sequentially transfers the cleaning processing tanks while gripping an object to be processed, such as a semiconductor wafer, with a transfer arm or the like. However, since it is a pretreatment of fine processing, it is desirable to shut off the respective atmospheres between adjacent cleaning processing tanks from the viewpoint of processing accuracy and yield. Therefore, the atmosphere shutter device requires not only the shutter speed but also a stable and reliable braking characteristic. Furthermore, since it is installed in a clean room, a small size, particularly a small size is desired.

The atmosphere shutter device in this embodiment is
It is installed between adjacent cleaning tanks and always has a shutter plate 6
0 is closed, and the shutter 60 plate is opened (down) when the object is passed. The shutter control unit and the driving unit are housed in a housing 62 at a position above the shutter plate 60. The rotation shaft of the induction motor 22 is connected to a pulley 66 via a transmission gear in a gear box 64, and a drive belt 68 is hung on the pulley 66. The drive belt 6 in the shutter housing and guide portion 70
8, a shutter plate 60 is connected via a joint. The rotational driving force of the induction motor 22 is converted into a linear driving force by the drive belt 68, and the shutter plate 68 moves up and down integrally with the drive belt 68. ing.

An electromagnetic brake 40 is integrally mounted on the back of the induction motor 22 in the housing 62, and a control box 72 for controlling the induction motor 22 and the electromagnetic brake 40 is provided behind the electromagnetic brake 40. In the control box 72, the primary windings 22A and 22B of the induction motor 22 and the primary winding 42 of the electromagnetic brake 42 in FIG.
All circuits except A, that is, the control circuit of this embodiment are accommodated.

In this atmosphere shutter device, the operation control signal DR + or DR- is turned off when the shutter plate 60 comes to a position short of a predetermined position to be stopped when the shutter is opened and closed, and the electromagnetic brake is applied to the induction motor 22 as described above. And the DC braking act simultaneously, whereby the shutter plate 60 is quickly stopped at a predetermined position. In addition, since no special large-capacity conducting element for DC braking is provided, the control box 72 is downsized, and the housing 62 and the entire apparatus are downsized.

FIG. 5 shows the configuration of a control circuit for a capacitor-type single-phase induction motor according to a third embodiment of the present invention. In the figure, parts common to the first and second embodiments (FIGS. 1 and 2) are denoted by the same reference numerals.

The third embodiment uses ordinary triacs 80 and 82 as bidirectional current-carrying elements connected in series with the primary windings 22A and 22B of the induction motor 22. The control terminals (trigger terminals) of the first and second triacs 80 are NPN emitter-grounded, respectively.
It is connected to the emitter terminals of the transistors 84 and 86 and is commonly connected to the emitter terminal of an NPN transistor 92 via diodes 88 and 90. NPN
The base terminals of the transistors 84, 86, and 92 respectively have a binary control signal DR + and a reverse control signal D +.
R- and the braking control signal BR are input. The collector terminal of the NPN transistor 92 is connected to the terminal of the power supply voltage Vcc via the phototransistor 14B of the photocoupler 14 and the resistor 94.

According to such a configuration, the first triac 80 is continuously turned on when the normal operation is performed, and the second triac 82 is continuously turned off when the normal operation is performed. 80 is continuously off and the second triac 82 is continuously on. When braking, both triacs 80 and 82 are simultaneously turned on only in a half cycle of one polarity, and are turned off simultaneously in a half cycle of the other polarity.

In the first to third embodiments, the triac connected in series with the primary winding of the induction motor is:
In general, a zero-cross type, which conducts from the zero-cross point of the current, is desirable, but a zero-cross type is also possible. It is also possible to variably adjust the DC braking force by giving a desired phase delay to the conduction point of the track. It is also possible to use another bidirectional energizing switching element or switching circuit instead of the triac.

The photocoupler for braking control is not limited to the phototransistor output type, but may be, for example, a photoMOS.
An output type may be used, and a transformer may be used instead of the photocoupler.

Although the above embodiment relates to a capacitor type single-phase induction motor, the braking control means or method of the present invention can be applied to other types of single-phase induction motors and three-phase induction motors. It is.

[0050]

As described above, the invitation in the present invention is performed.
According to the control circuit for the conductive motor, the first and second induction motors are controlled.
Bidirectional current-carrying type
Uses first and second photo triacs as opening / closing means
And at the time of braking, the first and second photo
Tie to turn on Iac every half cycle
Through the light emitting element from the AC power supply of the induction motor circuit.
The first and second photo trials
A first, a second, and a light emitting device, respectively.
In the third photo coupler, the first and second
Control circuit elements are powered from the triac and light-emitting elements.
The control circuit is significantly miniaturized and low
Cost reduction can be realized.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a circuit configuration of a control circuit of a capacitor-type single-phase induction motor according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a circuit configuration of a control circuit of a capacitor-type single-phase induction motor according to a second embodiment.

FIG. 3 is a timing chart showing a voltage or current waveform of each part for explaining an operation in the second embodiment.

FIG. 4 is a schematic perspective view showing a configuration of an atmosphere shutter device of a cleaning system to which a control circuit for an induction motor according to a second embodiment is applied.

FIG. 5 is a circuit diagram showing a circuit configuration of a control circuit of a capacitor-type single-phase induction motor according to a third embodiment.

FIG. 6 is a circuit diagram showing a configuration of a conventional control circuit for a capacitor-type single-phase induction motor.

[Explanation of symbols]

 10, 12, 14 Photocoupler 10A, 12A, 14A Light emitting diode 10B, 12B Phototriac 14B Phototransistor 16, 18 Diode 20 AC power supply 22 Induction motor 22A, 22B Primary winding 48, 50 Diode 52 Capacitor 54 Resistance

Claims (2)

(57) [Claims] A first and a second primary winding having different phases.
And one end of each of the first and second primary windings
Operation of an induction motor having a capacitor connected between
A control circuit for controlling the first and second primary windings for an AC power supply.
First and second phototriers connected in series, respectively
And a first photo triac in combination with the first photo triac.
A photocoupler, and emits light.
A first light-emitting element for turning on the memory, and a second photodiode in combination with the second phototriac.
A photocoupler, and emits light.
A second light emitting element for turning on a lock, and the second light emitting element for performing a forward rotation operation of the induction motor.
The first light emitting element continuously without causing the element to emit light.
Light is emitted to continuously turn on the first phototriac.
To perform the reverse operation of the induction motor.
The second light emitting element without causing the first light emitting element to emit light;
The second phototriac by continuously emitting light from the
And an operation control circuit for continuously turning on the power supply, and connected to the AC power supply and supplied from the AC power supply.
Conducts light only in a half cycle of one polarity of AC voltage and emits light
And a third photocoupler in combination with the third light emitting element.
Comprising, conducting when the third light emitting element emits light
Including a photoelectric conversion element for braking the induction motor
A light emitting diode which emits light every half cycle of the third light emitting element.
Half cycle of one polarity of the AC voltage in synchronization with
The first and second light emitting elements are simultaneously
The first and second phototriacs simultaneously
And a brake control circuit for turning on the induction motor.
Control circuit. 2. A third photo transformer for the AC power supply.
A primary winding connected in series with the earac, and
No-load operating electromagnetic operatively coupled to the rotor of a conductive motive
And a fourth brake in combination with the third phototriac.
A photocoupler, and emits light.
A fourth light emitting element for turning on the lock and the fourth light emitting element for rotating the induction motor forward or backward.
Turn on the light emitting element and turn off the third photo triac.
To turn on the electromagnetic brake,
Turn off the fourth light emitting element when braking the motive
To turn off the third phototriac,
An electromagnetic brake control circuit that turns off the magnetic brake
The control circuit for an induction motor according to claim 1, comprising: