SU1403311A1 - Electric drive - Google Patents

Abstract

The invention relates to electrical engineering and can be used in electric drives of conventional kanizm. The aim of the invention is to improve reliability. This goal is achieved by pre-magnetising the stator winding of the motor with a direct current, which ensures the creation of non-zero electromagnetic conditions that exclude the occurrence of sign-dynamic. moments when starting an asynchronous motor. The drive contains two contactors with coils 2 and 16, respectively. Contacts 3 and 4 of the first contactor provide connection of the thyristor 10 with a control circuit to the two phases of the stator winding for preliminary biasing of the stator winding of the asynchronous motor 1. 1 sludge. S (l

Description

4ib

About WITH

00

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

The purpose of the invention is to increase reliability.

The drawing shows a diagram of the drive.

The electric drive contains a three-phase asynchronous electric motor 1, a first contactor with a coil 2 with four loops) Sch No 1 and pins 3-6, one of which contact 3 is included in the first phase of the stator winding, the second closing contact 4 of the first contact after one; connecting to the power supply phase, sequentially connected to the 7-stop button,: the 8-start button, shunted by a third contact 5 of the first contactor, and; 2 the first contactor, the other: the output of which is provided with a clip for connecting to the same phase of the source power supply, another output of button 7 Stop is provided with a clip for connecting the power supply to the other phase, the closing contacts 9 of the second contactor are included in the second and third phases of the stator winding of the electric motor, the other end of the second contacting contact of the first 4 contactor is connected to the thyristor anode 10 and with one output of the adjustable resistor 11 and with the anode of the first diode 12, the cathode of which is connected to the thyristor 10 charging electrode and the anode of the second diode | 13, the cathode of which through parallel | connected resistor 14 | and con The sensor 15 is connected to the thyristor cathode 10 and to the third phase: the stator-winding of the electric motor,; the coil 16 of the second contactor is connected to one point through the fourth make contact 6 of the first ijoHTaKTopa connected to the junction point of the 7 Stop button and the Start button 8, the other В1Ы- Water coil 16 of the second contactor is connected to another output of coil 2 of the first contactor,

The device works as follows.

When the start button 8 is turned on, the coil 2 of the first magnetic starter is turned on, as a result of which a constant one half-sided current flows through the stator windings of the motor 1 due to the flow of current through the thyristor 10, with a control circuit

the parameters of which are selected in such a way that the direct current smoothly increases and reaches a steady-state value close to the rated motor current. When the coil 2 of the first contactor is turned on, its contact 5 closes, which shunts the Start button 8 and contact 6 in the coil 16 circuit of the second starter and which starts with a delay of about 0.2 s. During this time, about 10 half-waves of direct current will pass through the windings of the electric motor 1, and then the circuit of the thyristor 10 will be shunted by contact 9 of the second contacter. A three-phase voltage is applied to the motor and it is accelerated. In connection with the pre-biasing of the stator winding of the motor 1 by direct current, non-zero electromagnetic conditions are created which exclude the occurrence of alternating dynamic moments during the start of asynchronous motors.

Claims (1)

Invention Formula An electric drive containing a three-phase asynchronous motor, a first contactor with a coil and four make contacts, the first of which is included in the first phase of the motor stator winding, the second closing contact of the first contactor is connected to one phase to connect a power source connected in series with the Stop button, Start button, shunt the third closing contact of the first contactor, and the coil of the first contactor, the other output of which is provided with a terminal for connection to one phase of the source The power supply terminal, another output of the Stop button is provided with a clip for connecting to a different phase of the power source, which is also distinguished by the fact that, in order to increase reliability, a second contactor with a coil and two make contacts, a thyristor, two diodes, a resistor , a capacitor and an adjustable resistor, the closing contacts of the second contactor are included in the second and third phases of the stator winding of the electric motor, the other end of the second closing contact of the first contactor is connected to the anode of the thyristor and to one end of the adjustable re 314033114 of the resistor, the other output of which comes down It is not connected with the anode of the first diode, the cathode of the contactor through one of the cathodes, which is clearly connected to the controlling contact of the first closing contact of the first the thyristor electrode and the anode of the second contactor are connected to the connection point, the cathode of which through the parallel-stop button and the Start button, but interconnected coil of the second contact of the coil of the second contact capacitor connected to the cathode of the thyristor connected to another output of the coil torus and with the third phase of the stator winding of the first contactor.