SU59434A1 - Device for automatic contactor control of asynchronous motor - Google Patents

Description

A number of devices are known for automatic contactor control of asynchronous motors with phase rotors using a controller that includes individual contactors, the contacts of which, at the same time, remove a part of the resistance included in it from the rotor circuit.

The proposed device is due to parallel connection; resistance stages included in various combinations are made with a number of stages significantly larger than the number of contactors.

The engine is started and controlled in the proposed device as a function of the amperage, for which a current relay comprising two solenoids - acceleration and return, is in turn connected to the stator circuit of the motor, in turn, is controlled by the controller.

The drawing shows the schematic diagrams of the device proposed: FIG. 1 - power and FIG. 2 - urajleni chains.

Here and, 2J and so on. - coils and contactors of contactors, STU - solenoid current control, SU - acceleration solenoid, RBU -

acceleration solenoid blocking relay; SV — return solenoid; RBV — locking return solenoid relay; RPO — intermediate contactor of the zero contactor; QC — contacts of the “end controller” switch.

The order of operation of the circuit (for I value) is as follows.

The trenshalter in the stator circuit of the engine is switched on and fulfilled the necessary conditions for the operation of the motor. The controler.control.) And the slip is at the 1st position and the intermediate relay circuit of the solenoid of the oil switch VM is closed. The switch of the slip controller control circuit is turned on. The circuit breaks and triggers the circuit of the rotor through the resistance U and 8R. By pressing the Bk K 4aeticH button, the oil switch and the status switch receive a nominal value. Relay STU receives starting 6l ocoi {current and closes the relay circuit RBU. Relay RBU triggered and closes its contact in the solenoid circuit Usko {oi. The solenoid SU draws in its own Dechyik and thereby puts the controller on the 2nd position and turns on the contactor 2J, and 1J turns it off. Full

the rise, the core of the solenoid will open the normally closed contact in the RBU circuit. The RBU relay shuts down and opens the SU solenoid circuit. The solenoid SU is de-energized and releases the core. The core of the solenoid SU in the lowest (disconnected) position closes the -closed contact in the RBU circuit (in parallel with the self-feeding contact). Relay RBU receives power again and closes the circuit of the solenoid SU, which translates the commander “and the next 3rd position. In this sequence will continue: the operation of the relay RBU and the solenoid SU to the last position of the k-controller. When the K-controller will be put on the 15th position:.

1. The n-closed blocking contact is disconnected in the solenoid circuit of the SU and the RBU relay and de-energizes the latter.

2. A circuit is prepared for the bullet contactor O. Here the normal case is considered, i.e. the acceleration of the engine corresponds to the operation of the SU and the RBU. If the acceleration of the engine will go slower, and the RBU and SU will work faster than acceleration of the engine M, then the motor will begin to increase the current in the stator circuit, and consequently, the current in the STU relay circuit will increase. When the motor current reaches a value higher than the allowable one (on which the STU relay is installed), the STU relay opens its contact in the RBU relay circuit and, thereby, terminates the engine's further acceleration. If the current of the engine continues to increase, the relay of the STU will close its contact in the circuit - REV-I; the k-controller will start to go back and enters the resistance in- the motor circuit. Thus, the acceleration of the engine is under constant control of the relay. At the last (15th) position of the controller, the rotor circuit has minimal resistance, and the O contactor is prepared for the circuit from the controller. “On” - zero contactor O— is produced by the relay of the STU, when the motor reaches the current below the nominal value (by closing the contact of the STU in the RPO circuit). Turning the contactor on turns off all resistance in the rotor circuit and the engine continues to run with minimum slip, and therefore, with maximum speed. As already noted above, the STU relay closes the RPO circuit at the motor current below the nominal (85-90%). If we take into account the time of disconnection of RPO and O, then with increasing load the motor will receive resistance to the rotor circuit at rated current. The minimum resistance introduced into the rotor circuit will be insufficient and the engine will continue to gain load. When the motor current reaches the set value (120-130%), then the STU relay will close its contact in the RBV circuit. The RBV and CB solenoid relays will work similarly to the RBU and SU relays, only the CB solenoid will switch the K-controller in the opposite direction and thereby introduce resistance to the rotor until the engine load is limited to the STU relay setting. As soon as the engine load becomes lower than the set value, the STU relay closes the RBU relay circuit and the SU solenoid will begin to rotate the controller to accelerate the engine until the rotor is completely shunted. Thus, both the acceleration and deceleration of the engine occurs under the continuous control of the STU relay, whose operation depends on the load;

When the motor is disconnected from the mains, the STU relay loses excitation and releases its core, which, under the action of gravity and spring, moves to the zero position.

The core of the STU relay at the zero position will close its block-contact (parallel to its limit contact) in the RBV relay circuit. Relay RBV, having received power, will close the circuit of the solenoid CB and in such a sequence, as noted above, will transfer the K-controller to the 1st position. When the K-controller reaches the 1st position, it will open the blocking contact at the cost of the RBV and CB and deprive them of power. In the case of simultaneous relieving of voltage both from the engine power supply circuit and from the control circuit, the engine will not be restarted until the normal control system is in the 1st position. When the engine is restarted, the PR relay (intermediate relay of the solenoid of the oil switch) will be opened by the contact KK-1. The return keyboard (MF and RBV) will receive power immediately and take effect. When the K-controller reaches the 1st position and closes its contact in the PR circuit, then the engine can be turned on. In order to protect the engine from working with an open rotor, it is necessary to have a special relay connected to the control circuit of the slider regulator SPACE OF SEQUENCE OF RESISTANCE STEPS

with a contact in the circuit of the zero relay engine.

Unlike the 1st value, the 2nd value slip contactor controller has five individual contactors, giving 31 resistance levels, and one zero contactor. In connection with the increase in the number of start-regulating stages, the number of stages of the k-controller increases accordingly.

Everything else is the same as the 1st magnitude contactor grip regulator.

IN THE ROTOR CHAIN

1 VALUE

The subject matter of the invention.

The device for the automatic contactor control of the asynchronous motor by means of a controller, dT is used in order to control the slide of the motor depending on its size.

loads with a number of stages greater than the number of contactors; the control of the controller is performed by means of two solenoids — acceleration and return, activated by means of a current relay in the stator circuit.

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