SU1494186A1 - Ac electric drive - Google Patents

Abstract

The invention relates to electrical engineering and can be used in electric drives of industrial mechanisms. The purpose of the invention is to increase reliability by limiting the braking torque shock during self-excitation of the engine. This is achieved by transferring an asynchronous motor 1 with a phase rotor to self-excitation by sequentially switching on the rotor winding through a three-phase bridge rectifier 5 with two phases of the stator free phase of the stator through pin 9 and a diode connected to the anode group of the three-phase bridge rectifier 5, reducing the speed of the motor to half the synchronous indicated circuit of the free phase is open. In the electric drive, the shock braking torque of the electric motor is reduced during its self-excitation due to demagnetization of the asynchronous machine by the flow created by the free phase. 1 il.

Description

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The invention relates to electrical engineering and can be used in electric drives of industrial mechanisms.

The aim of the invention is to increase reliability by limiting the braking torque shock during self-excitation of the engine.

The drawing shows a diagram of the described electric drive.

The AC drive contains a three-phase asynchronous motor 1 with a phase rotor, a contactor with five closing and opening contacts, and the phases of the detachable winding of the electric motor 1 through three closing contacts 2 of the co-switch are designed to be connected to a power source, which is controlled by resistor 3 to the rotor motor circuits, between the sections of which include the fourth and fifth locking contacts 4.1, 4.2 of the contactor, a three-phase bridge rectifier 5, whose input is connected to the rotor winding phases, and d is bridged by capacitor 6 and connected via the closing contacts 7 of the brake contactor to the nepBoii and the second phases of the stator winding of the electric motor; electric motor, synchronous tachogenerator 10 is installed on the motor shaft, and its output through the contact 11 of the contactor is shunted by a variable resistor 12, the middle output of which is connected to the anode terminal of single-phase full-wave rectifier 13, the cathode terminal of which is connected to one of output you o- rows synchronous tachogenerator 10, a single-phase full-wave conclusions vshr peremenno1-1u DC converter 13 connected to the current coil of the contactor 14 of the buffer.

The drive works in a cjienyi-auuiM manner.

When giving the command to stop the drive, the motor 1 OTKiro u; - is supplied from the supply, the network by the contacts 2 of the contactor. In the rotor circuit, the days: the atsl is disconnected externally the star of the resistors 3 locks1,11 by means of contacts 4 con0

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tact1) a, and opening 1 by contact of this contactor, the coil 14 of the buffer contactor through the resistor 12 and the single-phase rectifying bridge 8 is connected to the synchronous tachogenerator 10 and connects the free clip to the buffer contactor I and I by contact 9 in series with diode 8 phase to the anode output of a three-phase bridge bridge of atel 5, the input of which is connected to the rotor of the engine. When: a) from the charge of the previously charged capacitor 6, through the locking 1e contacts 7 of the brake contactor, a discharge pulse is applied to two successively connected stator phases for r |,) 1st motor excitation.

IIu; i dm 1 by the effect of an external source, made in the form of a capacitor 6, the asynchronous motor 1 is self-excited and goes into generating brake mode. The demagnetizing action of the magnetizing force of a free (1) element eliminates the occurrence of a shock to the value of the brake torque of the engine at the time of its self-excitation.

The speed of the asynchronous motors 1 is controlled by the voltage of the synchronous tachogenerator 10, the position of the slider of the variable resistor 12 is set to the desired voltage of the coil 14 of the buffer contactor. When the drive motor rotates to half the speed, the synchronous buffer contactor is turned off and, with its 1m contact 9, opens the supply circuit of the free phase, excluding its demagnetizing effect on the motor .... At half the speed of the TopMosHovi engine, the torque is within acceptable limits.

The use of this invention eliminates electrical and mechanical overloads in the electric drive, limits the impact of the braking torque during self-excitation of the engine, and thereby increases the efficiency.

Claims (1)

Invention Formula AC drive containing three phases asynchronous motor with phase-wound rotor. a contactor with five closing and opening contacts, the phases of the stator winding of the motor through three closing contacts of the contactor are designed to be connected to a power source, starting regulating resistors in the rotor circuit of the electric motor, between sections of which are included the fourth and fifth closing contacts of the contactor, three-phase bridge rectifiers the driver, whose input is connected to the rotor winding phases, and the output is biased by a capacitor and connected to the first and second functions through the closing contacts of the brake contact a motor stator stator, characterized in that, in order to increase reliability by limiting braking torque shocks when the motor is self-excited, a synchronous tachogenerator, a variable resistor, a single-phase two-wave terminal, a buffer contactor with a coil and a jog pin are inserted in it. a diode whose cathode is connected to the anode output of a three-phase bridge rectifier; the anode of the diode is connected via a make contact of the buffer contactor to the third phase of the stator winding of the electric motor, the synchronous tachogenerator is mounted on the motor shaft, and its output through the disconnecting contact of the contactor is clamped by a variable resistor, the middle output of which is connected to the anode output of the single-phase full-wave rectifier, the cathode output of which is connected to one of the output terminals of the synchronous tachogenerator, in the single-phase two conductor paths of the single-component two components of the three components; connected to the coil of the buffer contactor.