Power Saver For Motor Equipped With Fault Safe Relay

摘要

PURPOSE: A power saving apparatus with a fault safe relay for a motor is provided to change to a non power saving state when a power saving apparatus gets out of order by controlling a phase of an input voltage by means of a microcomputer and a triac and controlling an application and application time of an input voltage. CONSTITUTION: An anode of an alternating current control triac(13) is electrically connected to a common power supply. A cathode of the alternating current control triac(13) is electrically connected to an overcurrent cut-off device. A wave monitor(14) detects when a current across the triac(13) becomes zero and outputs pulse signal. A setting value input terminal(11) selects and inputs a delay time. A signal input terminal of wave trigger(12) is connected to a gate of the triac(13). The wave trigger(12) outputs a trigger signal to the gate of the triac(13). A microprocessor(10) controls the wave trigger(12) to output a pulse to a gate of the triac(13) based on the pulse from the wave monitor(14) and the delay time from the setting value input terminal(11). A fault safe relay(15) includes first, second, and third contact points(RL1,RL2,RL3). The first contact point(RL1) is connected between an input power supply and the triac(13) in series. The second contact point(RL2) is connected between the triac(13) and an overload cut relay(16) in series. The third contact point(RL3) is connected between the triac(13) and the second contact point(RL2) in series. A power supply(17) supplies voltages necessary to each part of the circuits.