SU1411903A1 - D.c. electric drive - Google Patents

Abstract

The invention relates to electrical engineering and may find application in various production mechanisms. The aim of the invention is to increase reliability. The electric drive contains a nonlinear resistance, 8, connected between the second output of the excitation winding 7 and the common point of the core with the resistor of the starting KS circuit 4. The protective KS circuit 9 is connected in parallel to the thyristor 3. In this drive, the linear contactor and automatic protection against connecting the power supply in the wrong polarity. 1 il.

Description

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WITH

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The invention relates to electrical engineering and may find application in various production mechanisms.

The purpose of the invention is to increase reliability.

The drawing shows a diagram of the drive.

The DC motor contains an electric motor, measles 1-, which is connected in series with a starting resistor 2, a shunted thyristor 3, driving an RC circuit 4, connected in parallel to Core 1 and a thyristor 3. The midpoint of an RC circuit 4 is connected to common point 1 and anode of thyristor 3 through diode 5, and with control electrode of thyristor 3 through diistor 6. The common cathode point of thyristor 3, capacitor of the triggering RC circuit 4 and start-up resistor 2 is connected to one of the terminals of the parallel excitation winding 7. I Between the second output of excitation winding 7 and common point I with a resistor of the EC circuit 4, the nonlinear resistance 8 is connected, and a protective RC circuit 9 is connected in parallel to the thyristor 3.

I The control unit consists of a button station 10, a line contact with a winding 11, power contacts 12 and 13 and a block contact 14, a delay RC circuit 15, an optocoupler thyristor 16, a resistor 17 and a zener diode 18.

I The positive terminal 19 of the source of citation is through the first power contact 12 of the linear contactor, connected to the common point of core 1 and nonlinear resistance B, shunted by the closing contact 20 of the Stop button (button: station 10. Negative & WIRED 21 power sources via an optocoupler the thyristor 16 and the second power contact 13 of the linear contactor are connected to the common point of the cathode of the thyristor 3 and the starting resistor 2.

The winding 11 of the linear contactor, 1ntied by the capacitor 22 of the overriding RC-module 15, one output |: connected to the negative terminal 21 of the power supply JiCTO4HHKa and the cathode of the optocoupler thyristor 16. and through- (respectively, the included resistor 23 of the RC holding circuit 15, the closing

 14119032

contact 24 of the button. Start, disconnecting contact 25 of the button. Stop of the button station 10 - with a positive output 19 of the power source.

The control transition of the optocoupler thyristor 16 is shunted by a zener diode 18 and connected with a series-connected auxiliary contact 14 of a linear contactor parallel to the closing contact 24 of the Start button of the button station 10.

The drive works as follows.

15 When the Start button is pressed, contact 24 of the button station 10 is closed, which causes voltage to be supplied from the terminals 19 and 21 of the power source through the RC delay circuit 15 on

20 winding 11 of a linear contactor and through a resistor 17 to the transition anode - cathode of a closed optocoupler thyristor 1 6.

Voltage rise rate

25 of the anode of the thyristor 16 is limited by the action of the RC circuit 15, and the closure of the contacts 12 and 13 of the linear contactor occurs without current, since the thyristor 16 is closed at this time.

30 After the linear contactor is triggered and the Start button is released, the current of the winding 11 is transferred to the circuit, controlling the optocoupler thyristor 16 through the closed auxiliary contact 14 of the linear contactor. This leads to the opening of the thyristor 16 and the supply of the voltage of the power source to the excitation winding circuit 7, the core 1 and the triggering RC-circuit 4.

40 The first stage of the start of the electric motor with the starting resistor 2 connected in the circuit 1 begins. At the same time, the voltage rise rate at thyristor 3 is limited by the protective RC circuit 9 at the first moment.

50

55

At the time interval determined by RC circuit 4 and distor 6, the thyristor 3 turns on and shunts the starting resistor 2. The start switches to the natural mechanical characteristics of the switch, as the voltage on the core 1 of the electric motor becomes equal to the voltage of the power source.

In a static steady state operation with fluctuations in the supply voltage, the rotational speed of the electric motor is stabilized due to the introduced nonlinear resistance

five

At the time interval determined by RC circuit 4 and distor 6, the thyristor 3 turns on and shunts the starting resistor 2. The start switches to the natural mechanical characteristics of the switch, as the voltage on the core 1 of the electric motor becomes equal to the voltage of the power source.

In a static steady state operation with fluctuations in the voltage of the power supply, the rotational speed of the electric motor is stabilized by the introduction of a nonlinear resistor

8 into the circuit of the parallel excitation winding 7.

The motor is switched off by pressing the Stop button on the push-button station 10 for a time interval of 1-2 s. This opens contact 25 and closes contact 20 of this button.

Contact 25 breaks the control circuit of the optocoupler thyristor 16 and the circuit of the winding 11 of the linear contactor, which, however, remains switched on due to the action of the capacitor 22 of the delayed HC circuit 15.

The closure at the same time of the contact 20 leads to the shunting of the nonlinear resistance 8 in the circuit of the parallel excitation winding 7. Due to this, a transient forcing process arises - an increase in the current and excitation flow of the electric motor, accompanied by an increase in the back EMF and voltage on the core 1.

The nature of the interaction between the core and the circuit of the parallel field winding corresponds to the presence of positive feedback between these circuits, i.e. there is an increasing, avalanche-like increase in the excitation current and counter-emf of the engine, which in this case tends to go into the mode of generator (regenerative) braking.

At some point in time, when an increase in the counter-emf leads to a change in the direction of the current in the electric motor core circuit, the rptron thyristor 16 is turned off. Subsequent shutdown of the line contactor is accompanied by the opening of its power contacts in the de-energized state.

Claims (1)

Thus, the introduction of a nonlinear resistance, the EC circuit, the execution in an ordered manner; / the control unit stabilizes the speed, starts the thyristor from excessive voltage buildup, turns on the power contacts and turns off the line contactor in a de-energized state, protects the device from being connected to source in the wrong polarity, which increases the reliability of the drive. Invention Formula DC motor containing motor, measles 1903 which is connected in series with the starting resistor, shunted a thyristor that triggers the NS circuit connected in parallel to the kory and the thyristor, the middle point of which is connected to the common point of the thyristor core and anode through the diode, and to the control electrode of the thyristor - through the diode, while the common point of the thyristor The NS circuit and the starting resistor are connected to one of the terminals of the parallel excitation winding of an electric motor, 5 L, as well as a control unit and a power source, which, in order to increase reliability, includes a non-linear resistance, including A protective NS circuit connected parallel to the thyristor and a control unit made up of a night station button, a line contactor, a delayed NS circuit, an optocoupler thyristor, a resistor and a Zener diode , while the positive output of the power source through the first power 0 the contact of the linear contactor is connected to the common point of the core and the nonlinear resistance, shunted by the 1st contact of the button Stop of the button station, and the negative output of the power source through the optocoupler and the second power contact of the linear contactor is connected to the common point of the thyristor cathode and the starting resistor, the linear winding of the contact torus, shunted by a capacitor of the holding back NS circuit, is connected to the negative side of the power source and the cathode of the optocoupler thyristor by one terminal, and another black terminal of re5 ican connected to its anode through a resistor series-connected delaying NA chain, make contact Start button, Stop break contact keypad buttons station connected to the positive vy5 0 five power supply, the control transition of the optocoupler thyristor is shunted by a zener diode and connected with a series-connected contact contact of the line contactor parallel to the closing contact of the Start button of the button station.