SU760180A1 - REVERSING DEVICE FOR CONTROLLING A SINGLE PHASE CAPACITOR MOTOR 1 - Google Patents

Description

The invention relates to the field of instrumentation and can be used in magnetic recording equipment for automatic control of the speed of rotation of the drive shaft and 5 for stabilizing the tension or fast rewinding of the magnetic tape, as well as in other electroautomatic devices.

A device is known that includes ’one of a source of supply voltage of alternating current, an asynchronous single-phase capacitor motor, thyristor control elements, and 15 thyristor control circuit (ΐ].

The disadvantages of such a device include the low speed and reliability with reverse, which is detected using contact devices for switching one of the motor windings for the purpose of reversing. . .

Also known are devices that contain an AC power supply source, an asynchronous single-phase capacitor motor. The motor control windings are connected to the tires of 30

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Power supply And at one end - directly, and the other - through the primary windings of series-type transformers. The secondary winding of each transformer is connected to the diagonal of the diode bridge in alternating current, in the diagonal in direct current of which the thyristor is included. The control electrode of each thyristor is connected to the output of the control voltage source [2}.

The disadvantages of such a device include insufficiently high reliability and speed when reversing, as well as large dimensions and weight and / relatively narrow range of adjustable speeds. These shortcomings are due to the fact that seria-type transformers have low reliability (like any other winding units), and electromagnetic transients occur in them, significantly increasing the time of engine reversal. In addition, serial transformers compared with transistors have large, weight and size, higher saturation resistance and much less resistance in the closed state.

The aim of the invention is to improve the reliability and speed when reversing.

This goal is achieved by the fact that the device includes two optocouplers and an electronic switch with two inputs and two outputs, each of which is connected to the output of the emitter of one of the optocouplers, the opposite of which are connected to the output of the control voltage source, and the switch inputs are connected to the corresponding bus control panel, with the findings of the light-receiving devices of each optocoupler connected between the base of the regulating transistor and one of the terminals of the diagonal DC _; corresponding to the diode bridge.

One of the variants of the electrical concept of the reversing device for controlling a single-phase capacitor motor is shown in the drawing.

The device includes an AC power supply source 1, a control voltage source 2, a single-phase capacitor motor 3 with control windings 4 and 5, a phase-shifting capacitor 6, and 7 and 8 optocouplers. regulated-. transistors 9 and 10, diode bridges 11 and 12, switch 13 and control panels 14.

The principle of operation of the device is as follows.

If from the output of the source 2 of the control voltage to one of the terminals of the emitters of optocouplers 7, 8 to supply a positive potential, and from the output of the remote control 14 to apply a positive control potential to the input 15 of the switch 13, then through the emitter of the optocoupler 7 will flow current. The light will receive light signals from the emitter and the optocoupler 7 opens. To the input of the regulating transistor 9 from one of the terminals of the diagonal of the direct current of the diode bridge 11 through the light receiver of the optocoupler 7 comes a two-half-wave rectified voltage. Therefore, the regulating transistor 9 will be open to saturation and currents proportional to the voltage of source 1 will flow through the windings 4, 5 of the motor 3 control. Moreover, the current flowing through the winding 5 will be 90 ° ahead of the current flowing through the winding 4, since the phase-shifting capacitor 6 is connected in series with the winding 5. Therefore, the rotor of the electric motor 3 will rotate in agreement with

‘Direction of rotation of the stator magnetic field.

If from input 15 switch 13

remove the 'positive control potential supplied from the remote control 14, and feed the input 16 of the switch 13, the optocoupler 8 will open, and

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optocoupler 7 closes. In this case, the control transistor 10 will open and the transistor 9 will close. After the end of the electromagnetic transients in the windings 4.5 of the electric motor 3, the current flowing through the winding 4 will be ahead of the current flowing through the winding 5. Therefore, the magnetic field will change its direction of rotation, and therefore, the electric motor will be decelerated, since the moment developed on its shaft , coincides with the direction of rotation of the stator field. After a full stop, the rotor of the electric motor 3 will change the direction of rotation to the opposite. The braking time of the RotOr is determined by the electromagnetic and electromechanical time constants of the electric motors 3, since the control transistors 9 and 10, the switch 13 and the optocouplers 7 and 8 with a high degree of accuracy can be considered as non-inertial links that do not cause delays. and braking the motor 3.

The device provides a reversible control mode for single-phase capacitor motors, both asynchronous and synchronous.

Claims (1)

Claim A reversing device for controlling a single-phase capacitor motor, containing a control panel, AC voltage and control voltage sources, a two-winding motor, a phase-shifting capacitor, two diode bridges and two control transistors connected each by a collector and emitter to the diagonal terminals of one of the DC bridges, the first terminals of the diagonals for alternating current of which are connected to the first bus voltage source of alternating current, the second terminals - to the first water · motor windings between which capacitor plates are connected, and the second terminals of the motor control windings are connected to the second bus of an AC voltage source, characterized in that, in order to simplify, increase the reliability and speed of the device, two optocouplers and two inputs and two outputs, each of which is connected to the output of the emitter of one of the optocouplers, the opposite conclusions of which are connected to the output of the control voltage source, and the inputs mutator, are connected to the corresponding bus of the control panel, and the outputs of the light-receivers of each optocoupler are connected between the base 65 five 760180 6 regulating transistor and one of the terminals of the diagonal DC direct current diode bridge.