SU160738A1 - - Google Patents

Description

In the known devices for starting induction motors with the adjustment of the stator current, they are used as acceleration relays acting on contactors in the rotor resistance circuit of the motor, type RE-190 relays, but they are unreliable.

In the proposed device used three-winding relay. All relay coils are connected via rectifiers; the first is to the current transformer in the stator circuit of the motor, the second is in agreement with the first to the network, the third is opposite to the first to the network through a variable resistance to control the relay setpoint value.

The drawing shows a circuit diagram of the proposed device.

Each relay of three stages of acceleration has three windings. The windings / RUH-ZRU are connected via rectifier B to the current transformer TT in the stator circuit of the motor D. The windings IPy -5RU2 are fed through rectifier B-2 and AT transformer from the AC network (clamps 1 and 2), windings / RU-5RUz - from the same network through resistance

.

The windings of the switchgear URUh and / RU2 relays, for example / RU directed according to, the flow of the winding / RUZ is directed opposite to / RU1. When applying voltage to winding IPy, it turns on. With the help of resistance Ri, it is possible to change the ampere turns of the 1RU winding, and, therefore, the time delay setting of the relay. On the winding URU1 current flows proportional to the load of the engine.

The greater the load, the greater the winding / wrench and, hence, the time delay of the relay.

When the engine is turned off, the acceleration relays are turned on (the windings of the URU-ZRU2 are under voltage).

When the line contactor L is turned on, the stator of the motor is connected to the mains, in connection with these. Windings / RU-RU1 are powered, the 7RU-5RUz windings are turned on and the pull-down 1RU-2 turns off at the same time.

After the time delay has expired, the first-stage relay is activated and closes the contact / RU2 in the accelerator contactor / U circuit. The first stage of the rotor resistance is output and the torque of the engine increases. Turning on the contactor / V leads to the disconnection of the pull-in winding RU of the acceleration relay of the second stage.

After the time delay expires, the second stage relay, depending on the amperages in the current winding 2RU, and consequently, on the engine load, turns on the contactor 2U.

The inclusion of the remaining acceleration contactors is also carried out as a function of time with current correction.

When the last acceleration memory contactor is turned on, the engine goes to its natural characteristic.

Subject invention

A device for asynchronous motor start as a function of time with a stator current adjusted using acceleration relays acting on contactors in a motor's rotor resistance circuit, characterized in that, in order to increase the usefulness of the installation, the relays are triple-wound to be connected through appropriate rectifiers: first windings - to the current transformer in the stator circuit of the engine, the second one, connected according to the first, to the network, and the third, connected to the first one, to the network through an alternate satellite ix relay for controlling the magnitude of the setpoint.

Memory

L pg

1G

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