SU1300618A1 - D.c.electric drive - Google Patents

Abstract

The invention relates to electrical engineering and can be used in devices that require a smooth start of an electric motor. Reliability and smooth start of the motor 1 is provided by slowly reducing the inter-output voltage of the single junction transistor 14, as a result of which the phase angle of unlocking the thyristor 2 is reduced. A smooth reduction of the cross-base voltage of the single junction transistor 14 is achieved by charging the capacitor 11 through the resistor 15, diode 12, transistor- 13 and the resistor 16, which provides the connection of the variable resistor 6 with the unijunction transistor 14. 1 slug. (L 17 11 nisni5 5/5 00 o o o :, 00 72

Description

The invention relates to electrical engineering, in particular to a direct current electric drive, and can be used in an automated soft start electric drive.

The purpose of the invention is to increase reliability.

The drawing is a schematic of a DC motor drive.

The DC motor contains a DC motor, the root winding 1 of which is through the thyristor 2, and the excitation winding 3 is directly connected to the output of the rectifier 4. The thyristor 2 is shunted by a series-connected diode 5, a variable resistor 6 and a capacitor 7, the driver 8 pulses, the outputs connected to the control electrode of the thyristor 2, in addition, the electric drive contains resistors 9 and 10, a capacitor 11, a diode 12 transistor 13, a single junction transistor (OPT) 14, resistors 15 and 16, the second variable resis torus 17. At the output of the rectifier 4, a voltage regulator is connected to the series-connected resistor 18 and the zener diode 19, to the output of which is connected the input of the pulse shaper 8, the control input of which is connected through the resistor 9 to one output of the voltage regulator and to the second base of the single junction transistor 14, the first base of which through the resistor 10 and the emitter-collector junction of the transistor 13 is connected to the second output of the voltage regulator, also connected via series-connected circuits resistor 17, shunt capacitor 11, resistor 15 and diode 12 with the first voltage stabilizer connected via a resistor 16 to the emitter of the transistor 13, the base of which is connected to the engine of the second variable resistor 17. E1 1tter of a single junction transistor 14 6 and capacitor 7.

The device works as follows.

The voltage applied to the electric motor is controlled by changing the turn-on phase of the thyristor 2 by a relaxation generator on a single-transition transistor (OPT) 14 through a pulse shaper 8.

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The OPT is locked until the voltage at the emitter is less than the turn-on voltage, which is about 70% of the inter-base voltage. The voltage across the locked thyristor 2, which is the difference between the voltage at the output of the rectifier 4 and the back emf of the core, charges the capacitor 7 through a variable resistor 6 and diode 5.

The moment when the voltage on the capacitor 7 reaches the OPT turn-on voltage is determined by the counter electromotive force (engine speed), the position of the variable resistor 17. Turning on the OPT 14 causes the discharge of the capacitor 7 through the resistor 9. The resulting pulse through the pulse shaper 8 unlocks the thyristor 2.

When the thyristor 2 is open, the rectifier voltage 4 is applied to the motor core.

At the end of each half-period of the mains voltage, when it drops to zero, the thyristor 2 is locked again.

A smooth motor start is provided by slowly decreasing the OPT 14 baseline voltage, resulting in a decrease in the phase angle of the thyristor 2. A smooth decrease in the OPT 14 baseline voltage is achieved by charging the capacitor 11 through a resistor 15, a diode 12, a transistor 13 and a resistor 16 providing its b variable resistor 6 with a single junction transistor 14.

Thus, a smooth start and speed control of the electric motor is ensured in the electric drive, which increases the reliability of the electric drive.

Claims (1)

Invention Formula A DC motor containing a DC motor, the main winding of which is through the thyristor and the field winding directly connected to the output of the rectifier, said thyristor is bridged by a series-connected diode, variable resistor and capacitor, pulse generator, output connected to the control electrode of the thyristor , characterized by the fact that, in order to increase reliability, it has entered one hundred thirty-three thousand years voltage isolator, the second condensate is connected to the second output of the stabilizer, the second diode, the transistor, a single voltage junction, also connected transistor transistor, four slaughter through serially connected torus, the second variable resistor, the second variable resistor, shunt this at the output of the rectifier including the second capacitor, the third A voltage regulator, a resistor output and a second diode with the first one are connected to form an input, with a voltage regulator, a pulse, a control input connected through the fourth resistor with the latter is connected via the first resis emitter of the transistor, the base of which the torus to one output of the stabilizer is on-fO connected to the engine of the second variable and to the second base of the single junction resistor, the emitter of the single junction transistor, the first base of which transistor is co.cinen pogo through the second resistor and the emitter-point of the first variable resistor but-collector junction transistor and the first capacitor.