SU1334329A1 - Device for starting d.c.electric motor - Google Patents

Abstract

The invention relates to electrical engineering and can be used in various automation mechanisms with varying starting conditions. The aim of the invention is to increase the reliability of the device. The device contains serially connected direction 7 and variable resistor 8 connected between the middle points of the KS circuit and the core 3 circuit of the electric motor. gatel The control electrode of the thyristor 2 is connected to the collector of the transistor 9. The middle terminal of the variable resistor 8 is connected to the emitter of the transistor 9. 1 sludge. with ifi (Л 0 --- А IIXD (U) 4:; i Р

Description

one

The invention relates to electrical engineering and can be applied in various automation mechanisms with varying starting conditions.

- The purpose of the invention is to discover the reliability of the device.

The drawing shows a diagram of the device.

A device for electric motor start -JQ mainly along the circuit of transistor 9:

the capacitor 6 - the right part of the resistor 8 - the emitter junction, the transistor lecturer 9 - the control electrode-cathode junction of the thyristor

The direct current body contains a starting resistor 1, shunting transistors 2 and connected in series with motor 3 to the power source 4, to which is also connected the time setting CS circuit, composed of pesrfci 5 and capacitor 6, as well as a di- - nistor 7, a variable resistor 8 and a transistor 9, the middle point of the QC circuit is connected via a variable resistor 8 and a distor 7 to the output of the starting resistor 1, connected to the electric motor core 3, the base of the transistor 8 and di stories 7 and the collector-emitter junction of transistor 9 is connected between the control electrode of the thyristor 2 and an average output of the variable resistor 8,

The device works as follows.

When the device is connected to the power source 4 at the midpoint

the core circuit has a maximum positive potential (at the moment of switching on), and at the midpoint of the RC circuit there is a minimum. This is due to the fact that at the moment of switching on almost the entire voltage of the source is on the starting resistor 1, since its resistance is much greater than the resistance of the winding of the core 3 3 and on the capacitor 6, the voltage is almost zero, because before switching on the device At this time, the maximum reverse voltage is applied to the dynistor 7. As the motor accelerates, the voltage across the starting resistor 1 decreases, i.e. The positive potential of the midpoint of the core circuit decreases, while on the capacitor 6 it increases, i.e. the positive potential of the medium grows, the RC-ifenH point. At the moment when the potential difference between the average

VNIIPI Order 3977/55

Production polygr pr-tivd, Uzhgorod Proektna St., 4

13343292

the points of these circuits become equal to the voltage at which the dynistor breaks down, dynistor 7 punches through. A direct voltage drop across the resistor 8 for the input circuit of the transistor 9 is observed, and the capacitor 6 begins to discharge partially in the circuit of the cynistor 7 and

capacitor 6 - right part of resistor 8 - emitter junction - collector of transistor 9 - thyristor control electrode – cathode junction

2 - capacitor 6. This leads to the opening of the thyristor 2, a shunt starting resistor 1, and to a sharp decrease in the positive potential of the midpoint of the core circuit.

When the installation is turned off, the capacitor 6 is completely discharged along the circuit: resistor 5 - measles 3 - resistor 1e and the circuit returns to its original state,

In lightweight modes, the device is triggered after a shorter time interval after the moment of switching on and the engine quickly switches to natural mechanical conditions.

characteristic, and consequently, the nominal mode of operation.

Claims (1)

Invention Formula 35 45 A device for starting a direct current motor, containing a starting resistor, shunted by a thyristor and connected in series with the motor core to a Q power source, to which the time setting CS circuit, composed of a resistor and a capacitor, and a distor connected to the output CS are also connected. -Chain, characterized in that, in order to increase reliability, a variable resistor and a transistor are inserted into it, and the middle point of the KS circuit is connected to the output resistor through a variable resistor and dynistor a, the base of the transistor is connected to the common point of the variable resistor and dynistor, and the collector-emitter junction of the transistor is connected between the control electrode of the thyristor and the middle terminal of the variable resistor. , „Circulation 659 Under: SMS 50 55