JPS5842713B2 - Dendo Kinoseigyo Cairo - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control circuit for an electric motor, and more particularly, to a control circuit for an electric motor, which is provided with a timer circuit that controls the flow time of a braking current flowing through the main windings and auxiliary windings of the electric motor when stopping the electric motor. It is related to circuits.

Hereinafter, one embodiment of the present invention will be described with reference to the drawing of FIG.

In the figure, 1 is an AC power supply, and this AC power supply 1 includes a bidirectional three-terminal thyristor 2, a diode 3, and a motor 4.
The main windings 5 of the AC power supply 1 are connected in series, and the current of the AC power source 1 is passed through a bidirectional three-terminal thyristor 2, which is a control element that controls this current. It flows through the diode 3 and the main winding 5.

6 is connection A. B and a common contact C, and the contact A of this changeover switch 6 is connected to the auxiliary winding 7 of the motor 4, which is connected in parallel to the main winding 5 of the motor 4, and the phase advance capacitor 8. In a series circuit, the connection point between the auxiliary winding 7 and the capacitor 8 is connected to the connection point B, the connection point between the main winding 5 and the diode 3 is connected to the contact point B, and the connection point between the diode 3, the capacitor 9, and the resistor 10 is connected to the common contact point C. The anodes connected to the series circuit are respectively connected by diodes 11 connected in antiparallel through the series circuit.

Further, a series circuit of a capacitor 12 and a resistor 13 for protecting the bidirectional 3-terminal thyristor 2 is connected in parallel between the anode of the bidirectional 3-terminal thyristor, and this circuit is connected between the anode and the gate. A capacitor 14 is connected to prevent external noise from entering the bidirectional three-terminal thyristor 2.

Diodes 15 to 18 constitute a bridge-type rectifier circuit. In the bridge-type rectifier circuit constituted by diodes 15 to 18, the connection points of diodes 15 and 16 connecting the cathodes are as described above. A diode 1 whose anodes are connected to the collector of an NPN type transistor 19 which is a switching element that performs ON-OFF switching of the bidirectional three-terminal thyristor 2.
The connection points 7°18 are connected to the emitters of the transistors 19, respectively.

Between the base and emitter of the transistor 19 are a diode 20 for protection of the transistor 19 whose cathode is connected to the base, a resistor 21 for determining the input sensitivity of the transistor 19, a capacitor 22 for a timer circuit, and a timer circuit state. A series circuit with a resistor 23 is connected in parallel.

24 is a contact A which is interlocked with the changeover switch 6.

The capacitor 22 and the resistor 2 are connected to the contact B of the changeover switch 24.
The other end of the series circuit of a diode 25 and a resistor 26 whose cathodes are connected to the connection point with 3 is connected to the common contact C, and one end of the AC power supply 1 is connected to the common contact C, but there is nothing connected to the contact A. It is not connected, that is, it is in an open state.

In addition, in the bridge type rectifier circuit composed of the diodes 15 to 1'B, the connection point of the diodes 16 and 17 connecting the anode and the cathode is the bidirectional 3
A diode 15.18 whose anode and cathode are connected to the connection point between the anode of the second terminal thyristor and the cathode of the diode 3 in the same manner as the diode 16.17.
The connection point is connected to the connection point between the gate of the bidirectional three-terminal thyristor 2 and the capacitor 14 via a resistor 27 for limiting the gate current of the bidirectional three-terminal thyristor 2.

In the above configuration, when the electric motor 4 is rotated, the common contact C of the changeover switch 24 is switched to the contact B side.

At this time, the common contact C of the changeover switch 6 which is interlocked with the changeover switch 24 is also switched to the contact B side.

Switch the common contact C of the changeover switch 24 to the contact B side □
By doing so, the capacitor 22 is connected to the selector switch 24, the resistor 26 . Diode 25. Diode 18° Resistor 27. Via a bidirectional three-terminal thyristor 2 or a changeover switch 24. Resistance 26. Diode 25, diode 17. At the same time that the charging current flows through the bidirectional three-terminal thyristor 2, the charge charged in the capacitor 22 flows through the resistor 23 to the transistor 20.
turns on.

When the transistor 20 turns on, a current flows from the anode to the gate of the bidirectional three-terminal thyristor 2, thereby turning on the bidirectional three-terminal thyristor 2.

Since the common contact C of the changeover switch 6 is also switched to the contact B side, the diodes 3 and 11 are thereby switched to the contact B side.
are short-circuited in opposite directions, and the sine wave alternating current from the alternating current power supply 1 is applied to the main winding 5 of the motor 4, and the sine wave alternating current is applied to the auxiliary winding 7.
A sine wave alternating current having a phase different from that of the sine wave alternating current flows, and the motor 4 starts rotating.

``Next, when stopping the electric motor 4, the common contact ``C'' of the changeover switch 24 is switched to the contact A side.

At this time, the transformation contact C of the changeover switch 6 is also switched to the contact A side, as described above.

By switching the common contact C of the changeover switch 24 to the contact A side, charging to the capacitor 22 is cut off, and at the same time, the electric charge stored in the capacitor 22 is released to the transistor 9 via the resistor 23. .

While the electric charge stored in the capacitor 22 is being discharged to the transistor 19, the bidirectionality 3 is activated as in the above explanation.
Terminal thyristor 2 is ONL.

□ ゛Then, since the common contact C of the changeover switch 6 is also switched to the connection A side 1, while the bidirectional three-terminal thyristor 2 is ON, the main winding 5 of the motor 4 receives a half □ cycle. A current with a half-wave rectified waveform flows through the diode 3, and the auxiliary winding 7 receives a half-cycle half-wave rectified waveform in the opposite direction to the half-wave rectified current flowing through the main winding 5. The current flows through the changeover switch 6 and the diode 11.
I go through books and it flows.

That is, the alternating current of the alternating current power source 1 flows through the main winding 5 and the auxiliary winding 7 of the motor 4 for half a cycle each.

As a result, the electric motor 4 quickly stops once, and the braking force at any time is extremely large.

Also, when the charge stored in the capacitor 22 is discharged and the □' register 19 is turned off,
The bidirectional J-terminal thyristor 2 is also turned off, and the braking current to the motor 4 is cut off.

Here, the time during which the braking current flows to the motor 4 can be adjusted by adjusting the resistance value of the resistor 21, which determines the input sensitivity of the transistor 19, in addition to adjusting the time constant by the capacitor 22 and the resistor 23. Even in the case of motors with different capacities, the time during which the braking current flows can be easily adjusted by changing the resistance value of the resistor 21.

Moreover, since the time adjustment is performed by adjusting the input sensitivity of the transistor, the resistor 21 used for the time adjustment can be a small-power variable resistor.

The capacitor 22 is a capacitor for the 1.9 time limit circuit, but it is also a smoothing capacitor that allows direct current to flow through the base of the transistor 19.

The circuits shown in FIGS. 2 to 4 are other embodiments of the time limit circuit of the motor control circuit shown in FIG. 1, and the same parts as those in the circuit shown in FIG. .

The timer circuit shown in FIG.
8, and as mentioned above, the transistor 19
By adjusting the input sensitivity of the motor 4 using the variable resistor 28, the time during which a braking current flows through the motor 4 when the motor 4 is braked can be adjusted even if the capacity of the motor 4 changes.

In addition, the time limit circuit shown in FIG. 3 has a thermistor 29 connected in series with Mm21, and in this case, the transistor
The thermistor 29 is connected in series with the resistor 21 to prevent the input sensitivity of the motor 9 from changing due to changes in temperature, which changes the time during which the braking current is applied to the motor 4 and makes the braking of the motor 4 unstable. Therefore, even if the input sensitivity of the transistor 19 changes due to a change in temperature, the thermistor 2
9 compensates for this, so that the braking of the electric motor 4 becomes stable.

Further, the time limit circuit shown in FIG. 4 has a Zener diode 30 connected in parallel to the capacitor 22, which stabilizes the voltage after the P capacitor 22 is charged.

Of course, the resistance 21 can be adjusted for the time during which the braking current flows through the electric motor 4.

In the present invention, a thyristor may be used instead of the transistor 19 as a switching element of the bidirectional three-terminal thyristor 2, and a thyristor may be used as a control element for the current flowing in the main winding 5 and the auxiliary winding 7 of the motor 4. In addition to the tropic three-terminal thyristor 2, thyristors, electromagnetic relays, etc. can also be used.

As described above, according to the present invention, the flow time of the braking current flowing through the main winding and the auxiliary winding when stopping the motor can be easily adjusted, so the control circuit of the present invention can be applied to a motor of any capacity. This is a very good thing that can be done.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a control circuit for a motor equipped with a time limit circuit according to an embodiment of the present invention, and FIGS. 2 to 4 are circuit diagrams of time limit circuits according to other embodiments of the present invention. ... AC power supply, 2 ... Bidirectional 3-terminal cyrisk, 4 ... Electric motor, 5 ...
Main winding, 7... Auxiliary winding, 19... Transistor, 22... Capacitor.

Claims (1)

[Claims] 1. A main circuit having an AC power supply that supplies alternating current and braking current to the main windings and auxiliary windings of the motor, and a control element that controls the alternating current of this AC power supply, and the control element of this main circuit and the main winding of the motor. , an eleventh second diode inserted and connected between the auxiliary winding and the connection between the eleventh second diode and the main winding and the auxiliary winding of the motor are switched between when the motor is rotating and when the motor is stopped. A switching circuit having a switching means, a switching element whose input sensitivity is adjustable for switching the control element of the main circuit, and a capacitor that controls the switching element and is charged and discharged by the alternating current of the alternating current power supply. When the motor is in a rotating state, the capacitor is charged and the electric charge charged in the capacitor is passed through the switching element to make the switching element conductive, and the switching element makes the control element conductive. An alternating current is passed through a main winding and an auxiliary winding of the motor through an eleventh second diode to rotate the motor, and when the motor is stopped, charging to the capacitor is cut off and the capacitor is discharging. The discharged charge is caused to flow through the switching element to make the switching element conductive, thereby making the control element conductive, and a half-wave rectified current is caused to flow through the main winding of the motor via the first diode, and a second half-wave rectified current is caused to flow through the auxiliary winding.
A motor control circuit configured to flow a half-wave rectified current in the opposite direction to the half-wave rectified current flowing through the main winding through the diode.