Single-phase asynchronous motor driver

Abstract

The invention discloses a single-phase asynchronous motor driver including a main winding branch and an auxiliary winding branch. The main winding branch and the auxiliary winding branch are connected to a power output terminal of a single-phase power switch after being connected in parallel. The main winding branch includes a main winding and an undervoltage winding. The undervoltage winding is connected with the main winding in parallel after being connected with a contact of a relay in series. The auxiliary winding branch includes an operation capacitor, a starting capacitor and an auxiliary winding. The starting capacitor is connected with the operation capacitor in parallel after being connected with a centrifugal switch in series and is then connected with the auxiliary winding in series. A control circuit is also connected to the power output terminal of the single-phase power switch in parallel and includes an integrated operational amplifier, a trigger and a relay. The drive circuit is reasonable in design and simple in structure, can ensure normal operation of a motor in normal voltage and also can ensure the safe operation of the motor in an undervoltage condition.

Description

technical field [0001] The invention relates to a single-phase asynchronous motor, in particular to a driving circuit of the single-phase asynchronous motor which can work normally under undervoltage conditions. Background technique [0002] Single-phase asynchronous motor is an electric device with simple structure, reliable operation and high cost performance. It is not only widely used in industrial and agricultural production, but also in household appliances. The existing single-phase asynchronous motor is mainly composed of main winding, auxiliary winding, rotor, running capacitor, starting capacitor and centrifugal switch. [0003] In actual operation, since the torque of the motor is proportional to the square of the voltage, under the undervoltage condition of insufficient voltage, the torque of the motor decreases, so when the same load is dragged, the speed will decrease and the slip will increase. If the motor current increases, but the motor resistance remains ...

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Problems solved by technology

[0003] In actual operation, since the torque of the motor is proportional to the square of the voltage, under the undervoltage condition of insufficient voltage, the torque of the motor decreases, so when the same load is dragged, the speed will decrease and the slip will increase. If the motor current increases, but the motor resistance remains unchanged, the motor will heat up seriously; in addition, the motor speed will decrease and the motor coaxial cooling fan speed will decrease, which will make the cooling effect worse, aggravate the heat generation of the motor, and make the motor unable to work normally. until burned out

In the prior art, in order to avoid the undervoltage operation of the motor, the undervoltage protection device can only be used. Its function is to protect the motor from automatically breaking away once the undervoltage operation occurs. Therefore, the current single-phase asynchronous motor cannot work normally under the undervoltage condition. run

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