POWER FAILURE PROTECTION CIRCUIT, ANGLE GRINDER HAVING POWER FAILURE PROTECTION, AND CIRCUIT OF THE ANGLE GRINDER

摘要

A power failure protection circuit, an angle grinder having power failure protection, and a circuit of the angle grinder. The power failure protection circuit comprises: a resistive and capacitive step down circuit having an input end thereof parallel-connected to an input end of a load circuit, a bidirectional triode thyristor serial-connected to the load circuit, and a single-chip microcomputer that is supplied with electricity by the capacitive and resistive step down circuit. The angle grinder having power failure protection comprises: a power supply input end, a motor circuit, the power failure protection circuit electrically connected between the power supply input end and the motor circuit, and a wye-delta capacitor circuit electrically connected between the motor circuit and the power failure protection circuit. The power failure protection circuit causes no interference to electrical equipment while effectively protecting the safeness of the electrical equipment, the angle grinder having power failure protection prevents automatic startup of the angle grinder in a case that the angle grinder looses power suddenly then reacquires power suddenly, thus preventing the angle grinder from causing hazards due to uncontrolled automatic operation.