No contact energy-saving starter

Abstract

The present invention relates to a contactless enegy-saving starter which is characterized in that: the device includes a PTC thermosensitive resistor Rp, a three-end bidirectional controllable silicon T, a photocoupler U, a sensor L and a rectifying bridge D. In the present invention, a photocoupler U is used to trigger the three-end bidirectional controllable silicon T, thus, the situation that the controllable silicon is not conducted and stopped absolutely because of the un-synchrony of the phase of the triggered control signal and the started loop is avoided, and the reliability is improved greatly. Thus, not only the successful stating of the electric motor is assured, and the started loop is broke absolutely because the bidirectional controllable silicon is stopped absolutely after the starting is achieved. The energy consumption by the thermosensitive resistor Rp is eliminated because there is no current flowing through the PTC thermosensitive resistor Rp.

Description

Technical field [0001] The invention relates to a starter, in particular to a non-contact energy-saving starter for a single-phase AC induction motor. Background technique [0002] A single-phase AC induction motor is generally composed of a stator and a rotor. The stator is composed of a main coil L1 and an auxiliary coil L2. The auxiliary coil L2 mainly works when the motor starts, and the main coil L1 works when the motor is running in a steady state. For any motor to run normally, it needs a good starting process. For the starting of a single-phase AC induction motor, it is necessary to connect a starter similar to a switch in series in the secondary coil circuit; it is required to be connected when the motor starts. The secondary coil L2 loop should be disconnected in time after the motor is started. A conventional motor starter is usually just a PTC thermistor with a positive temperature coefficient characteristic. If the power is turned on to the motor, a large curr...

AI Technical Summary

Problems solved by technology

The sampling part of the mutual-inductance non-contact starter is not really isolated from the trigger circuit of the bidirectional thyristor. The main coil of the motor or the main power supply circuit still has the influence of electromagnetic interference on the trigger circuit through the current transformer.

In addition, the mutual inductance non-contact starter cannot complete the starting task in the occasions where the starting capacitor is not required to be connected in series to the secondary coil of the motor, and for motors with different rated operating current specifications, current transformers with different parameters must be selected. One-by-one matching is required to work properly, and the versatility is greatly limited, thereby reducing the scope of application

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