Mutual-induction type contactless starter

Abstract

The invention provides a mutual-induction type contactless starter for starting a compressor motor and a conventional single-phase alternating current induction-type or permanent-magnetic-type motor. The mutual-induction type contactless starter comprises a current transformer L comprising a primary coil and a secondary coil, a bidirectional silicon controlled thyristor T and a positive temperature coefficient (PTC) thermistor PTC, wherein the end 1 of the primary coil of the current transformer L is connected with one end of a power end and the first electrode A1 of the bidirectional silicon controlled thyristor T; the end 2 of the primary coil of the current transformer L and the end 4 of the secondary coil are connected with the leading-out end M of the primary winding of the motor; the end 3 of the secondary coil of the current transformer L is connected with the trigger electrode G of the bidirectional silicon controlled thyristor T; and the second electrode A2 of the bidirectional silicon controlled thyristor T is connected with one end of the PTC thermistor PTC, and the other end of the thermistor PTC is connected with the leading-out end S of the secondary winding of the motor. Accordingly, the mutual-induction type contactless starter can increase the energy efficiency; the mutual-induction type contactless starter has the advantages of simple circuit, small component number and reliable components; and the mutual-induction type contactless starter can ensure the function of starting the motor and improve the reliability of the starting system of the motor at the same time.

Description

technical field [0001] The invention relates to a mutual-inductance non-contact starter, which is mainly used for starting compressor motors, and can also be used for starting common single-phase AC induction or single-phase AC permanent magnet motors, hereinafter collectively referred to as single-phase AC motors. Background technique [0002] A single-phase AC motor usually consists of a rotor and a stator consisting of primary and secondary windings. In addition to the function of starting the motor, the auxiliary winding can also continue to work when the motor is running normally, so the auxiliary winding circuit of a complete single-phase AC motor can usually be represented by a parallel auxiliary winding running circuit and auxiliary winding starting circuit . When the motor is running normally, the motor whose auxiliary winding does not participate in the work does not have the auxiliary winding running circuit part. Among them, the starting circuit part of the aux...

AI Technical Summary

Problems solved by technology

Resistors are purely resistive components, and the current of the total circuit of the motor is usually at or near the ampere level, so that during the entire operation of the motor, the resistor consumes useless heat dissipation at or near the watt level

This circuit also greatly reduces the utilization rate of energy while being able to start the motor

In addition, the circuit uses auxiliary circuits such as "reference current setter" and "comparison circuit". The existence of these auxiliary circuits reduces the reliability of the motor starting function to a certain extent.

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