JPS5869496A - Reversible variable speed shifting gear for motor - Google Patents

Abstract

PURPOSE:To stably perform reversible variable speed shifting of a condenser run type motor by detecting the zero point of the speed at the time of switching the rotating direction of the motor, thereby performing the switching between the drive side and the brake side and the switching of a thyristor. CONSTITUTION:A condenser run type motor having balance winding coils 2, 3 and a condenser 4 is connected through thyristors 7, 8 to a power source 1. The output of a speed detector 13 is compared with that of a speed setting controller 12, the zero speed is detected by a comparator 17, is introduced to a synchronizing signal control circuit 11 having switching circuits 22, 23 for switching the output of a synchronizing signal circuit 21 via a flip-flop 20, thereby controlling gate trigger circuits 9, 10. Accordingly, the speed is first set to zero in the braked state at the time of switching the rotating direction, and the switching to the drive side and the switching of thyristors 7, 8 are performed, thereby extremely stable switching can be conducted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reversible variable speed device for a motor that performs reversible variable speed control of a capacitor-operated single-phase induction motor using a primary voltage control method.

Conventionally, non-reversible variable speed devices have been known as variable speed devices for capacitor-operated single-phase induction motors using the same method, and when reversible, as shown in Figure 1, the variable speed device is Motor winding 11.21 and driving capacitor 3'
This was done by switching the connections. In addition,
6' is a tacho generator that detects the speed of the electric motor, 6'
is a control device that controls the speed of the electric motor.

However, in the above configuration, the electric motor rotates in the normal direction.

The reverse rotation is switched by switching the contact 4' of the electromagnetic switch, which poses a problem in the life of the contact and also in that the direction of rotation cannot be switched depending on the timing of forward/reverse switching.

In general, the S-T characteristics of the rotational speed S and torque T of a capacitor-operated single-phase induction motor at a synchronous speed of 10N8 to -N8 will vary depending on the power supply frequency and the capacitance value of the operating capacitor, as shown in Figure 2a. The characteristics change as shown in Figure 2.

When the winding of a capacitor-operated single-phase induction motor having the characteristics shown in Figure 2, in which the characteristic region M exists in the direction of negative torque, is switched between forward and reverse rotation, the direction of rotation is changed. First, there was a possibility that the rotation would continue to 1 in the rotation direction before switching. Further, even if forward/reverse switching is possible in a 60 Hz region, switching may become impossible when operated in a 50 Hz region. In addition, in FIG. 2, the vertical axis shows torque, and the horizontal axis shows rotational speed.

The present invention has been made in view of the above-mentioned points, and is basically a reversible variable speed device by adding a forward/reverse control circuit to a non-reversible variable speed device using primary voltage control of a capacitor-operated single-phase induction motor with balanced windings. This is what I did.

The basic irreversible variable speed device has control characteristics as shown in FIG. 3, and is capable of continuously controlling the driving region and the braking region as shown in the control section B.

1. When switching the rotation direction, the forward/reverse control circuit reduces the speed by first switching the speed setting to zero speed setting, instead of suddenly switching the motor windings and connecting the motor to reverse rotation. Then, when the speed is zero, the synchronizing signal of the gate trigger circuit of the bidirectional thyristor connected between each winding of the motor and the power supply is switched between full-wave phase control and half-wave phase control, and the drive side At the same time as switching the brake side, the trigger phase control signal to the gate trigger circuit is swapped to electrically switch between forward and reverse rotation, and then the zero speed setting is switched to a predetermined speed setting to control the speed in the reverse rotation direction. It is something.

Next, the overall configuration of the present invention will be explained with reference to FIG. 4. In the figure, 1 is an AC power supply, 2 and 3 are the windings of a lance-wound capacitor-operated single-phase induction motor, and 4 is a driving capacitor with one end connected to winding 2 and the other end connected to winding 3. ,
6 and 6 are connected in series to the windings 2 and 3, or actuators, and 7
, 8 are bidirectional thyristors connected in series to the windings 2.3, 9.10 are gate trigger circuits connected to the gates of the bidirectional thyristors 7.8, 11 are gate trigger circuits 9, This is a synchronous signal control circuit that electrically performs forward/reverse switching by replacing the trigger phase control signal to 1o, and together with the speed setting control circuit 12, constitutes a forward/reverse control circuit. 13 is a speed generator (AC tacho generator) that detects the rotational speed of the electric motor, 14 is a speed generator 1
16 is an error amplifier that amplifies the difference between the speed setting signal from the speed setting control circuit 12 and the rotation speed detection signal from the speed generator 13; 16 is the rotation direction of the motor; This is a rotation direction switch for changing the rotation direction.

In the above configuration, the synchronization signal control circuit 11 includes one-way ND circuits 18 and 19 that gate-control the forward and reverse logic signals controlled by the comparator 17 that detects zero speed.
The flip-flop circuit 20 is set and reset by the output of the ND circuit 18゜190, and the signal is taken out from both ends of the bidirectional thyristor 7゜8 to perform half-wave phase control and full-wave phase control. A flip-flop is connected between the synchronization signal circuit 21 and the gate trigger circuits 9 and 100 to generate a synchronization signal, and to make the synchronization signal output full-wave phase control during driving and half-wave phase control during braking. The first switch circuit 22 performs a switching operation based on the output of the circuit, and the output of the error amplifier 16 is connected between the error amplifier 15 and the gate trigger circuits 9 and 1o to perform phase control (trigger phase angle control). The second switch circuit 23 switches the synchronization signal for controlling the phase of the bidirectional thyristor 7.8 and switches the trigger phase control signal to electrically switch between forward and reverse directions. It is something.

Note that the comparator 17, the AND circuit 18, and the flip-flop circuit 20 keep the speed close to zero.

The speed setting control circuit 12 also has an exclusive (ExC
LUSIV[)OR circuit 24.26 and this exclusive OR
an OR circuit 26 that takes the logical sum of the outputs of the circuits 24 and 25;
An inverter 27 connected to the output end of the OR circuit 26 sets the speed thermal constant signal to zero speed when the forward/reverse switching signal does not match the output of the flip-flop circuit 20 using the output of the OR circuit 26 and the output of the inverter 27. A third switch circuit 28 generates a signal So and generates a required setting signal 8i when they match.

- Next, the operation of each part when the rotational speed is changed from 10N1 to -N2 will be explained with reference to FIG. In addition, in FIG. 4, man and n are bidirectional thyristors 7 and 8, respectively.
A synchronizing signal for full-wave phase control, signal B, (3 is a synchronizing signal for half-wave phase control. Also, in FIG. 6, N, R, E, F are digital signals, Si, 8. V is an analog signal, and V indicates the rotational speed of the motor.
9-Now, at the time of T1, turn the rotation direction selector switch 1.
6 to change the rotation direction from IN to H, and at the same time change the speed setting from 81 to 82 to change the rotation speed from 10N1 to -
When trying to switch to 12, flip-flop circuit 2
o output IC, F and rotation direction setting signal N.

Since R no longer matches, the speed setting signal S is set to zero speed setting So, and the brake is applied to the electric motor to reduce the speed to v8, at which point IT2 is set. At this time point 72, the rotational speed is close to zero speed, which is not in the area M in FIG. At the same time as the reverse connection is switched, the rotation direction setting signals N, R and the outputs E, F of the flip-flop circuit 2o match, so the speed setting signal is switched from zero speed setting SO to S2, and the motor is -N2- It accelerates at 1 and stabilizes at 75.

FIG. 6 shows an example of application of the present invention.)IJ.

When the forward and reverse logic inputs to the block flop circuit 2o are both H or L, the output becomes L, and the subsequent synchronization signal control circuit 11
A control circuit 32 including an exclusive OR circuit 29 and AND circuits 30 and 31 is added to prevent output of the synchronization signal and trigger phase control signal.

Also, in FIG. 7, the speed setting signal St is positive.

Additional circuit 3 when using negative polarity, controlling the rotation direction using polarity, and setting the rotation speed using absolute value.
3, the additional circuit 33 is composed of an absolute value amplifier 34, a polarity detector 36, and an inverter 36.

FIG. 8 shows an example of the configuration of the synchronization signal circuit 21.
is a bidirectional thyristor, 38.43.

44.45 is a resistor, 39.40 is a Zener diode, 41.42 is a photocoupler, 46 and 4 are diodes, and 48 is a DC power supply, which is connected in reverse series with the resistor 38 across the bidirectional thyristor 37. zener diode 39
．． Connect a circuit with the input diodes of 41 and 42 in anti-parallel through the photocube through 40'i, and take out the applied current of the bidirectional thyristor 37.
This becomes the synchronization signal for half-wave phase control, and the diode 46
By combining the outputs of both photocouplers 41 and 42 using i47 and resistor 44, a synchronizing signal L2 for full-wave phase control can be generated.

When performing half-wave phase control, either L1 or L5 is used. In addition, when used in the circuit of FIG. 4, the circuit of FIG. 8 is connected to each bidirectional thyristor, and a set is required.

As is clear from the above explanation, according to the present invention, compared to a conventional primary voltage controlled non-reversible variable speed device that is made up of a reversible variable speed device by adding an electromagnetic switch, It is possible to provide a reversible variable speed device that eliminates restrictions on the ST characteristics of a phase induction motor and can perform reliable variable speed operation using a non-contact system and appropriate control no matter what S-D characteristics.

Furthermore, compared to the most common DC servo system as a servo mode, it has excellent effects such as being able to provide a low-cost reversible variable speed device and eliminating the need for maintenance such as brush replacement.

[Brief explanation of drawings]

Figure 1 is a circuit diagram of a reversible variable speed device for a conventional capacitor-operated single-phase induction motor, Figures 2a and b are characteristic diagrams showing the relationship between rotational speed and torque of the same motor, and Figure 3 is the invention of the present invention. FIG. 4 is a circuit diagram of a reversible variable device for an electric motor according to an embodiment of the present invention.
Figure -6 is an operating waveform diagram of each part when the rotation speed is changed from 10N1 to -N2 using the same device, Figures 6 and 7 are circuit diagrams of other embodiments of the present invention, and Figure 8 is FIG. 2 is a circuit diagram showing a specific configuration of a synchronization signal circuit in the device of the present invention. 2.3...Winding, 7,8...Bidirectional thyristor, 9,10...Gate trigger circuit,
11... Synchronous signal control circuit, 12...
Speed setting control circuit, 14...Speed generator, 16
・・・・・・Choice switch. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 12 Figure 3 Figure 4 Si Figure 6 One clear space Figure 8

Claims (1)

[Claims] (1) A rotation direction changeover switch that changes the rotation direction of the electric motor, a speed generator that detects the rotation speed of the electric motor, and two connected in series to the main winding and auxiliary winding of the electric motor, respectively. a bidirectional thyristor, a gate trigger circuit connected to the gate of this bidirectional thyristor, and a synchronization signal and a trigger phase control signal of this gate trigger circuit,
a synchronous signal control circuit that electrically switches between forward and reverse directions;
A zero speed setting signal is output when switching the rotation direction, and the electrical positive amount is controlled by the synchronization signal. (2) The synchronization signal control circuit includes a memory circuit whose output state can be switched only at low speeds close to zero speed, and the output of this memory circuit allows the synchronization signal of the synchronization signal circuit to be controlled between full-wave phase control and half-wave phase control. The speed setting control circuit includes a first switch circuit that switches the trigger phase angle control signal of the bidirectional thyristor, and a second switch circuit that switches the trigger phase angle control signal of the bidirectional thyristor. 2. The reversible variable speed device for an electric motor according to claim 1, further comprising a third switch circuit for switching the speed setting signal to the zero speed setting signal. @) The synchronization signal circuit is separated from the polarity of the voltage applied to the bidirectional thyristor by means of a photocoupler connected in antiparallel to both ends of the bidirectional thyristor. Method (4) The memory circuit has forward rotation and reverse rotation signals in phase t'.
When the level is high or low, the first switch circuit and the second
3. The reversible and reversible transmission device for an electric motor according to claim 2, further comprising a damping circuit for turning off the switch circuit. ←) The speed setting control circuit outputs the speed setting signal to the plug 37.
Claim 2, wherein the varnish, negative polarity signal and speed setting are configured as absolute values, and the forward/reverse control circuit is configured to obtain a forward/reverse switching signal using a polarity detector. Reversible variable speed device for the electric motor described.