Simple fail safe loss of any phase prevention circuit

This is a very simple fail safe electrical circuit to prevent single phasing or prevent damage caused by phase loss especially to motors. The output is a control voltage which can be any type of ac or any type of dc supply, voltage for motor circuitry or for a main incomer breaker with under voltage trip relay coil. 2 relays can also be used if supplied by 2 phase voltages to 2 relay coils in case of a 3 phase system. Relays can be increased for a polyphase supply. Although the response time is in milliseconds but more than that of a single phasing relay that uses electronic, solid state components but is sufficient to protect from damage to electrical components like motors, etc due to phase loss. Operational amplifiers can also be used for phase loss, under voltage, over voltage protection and their output can be directly fed to the control circuit by current buffers and they are faster than mechanical relays for those applications where response time required is less than milliseconds for real time applications. This electronic circuit will be posted latter on.

published 4 years ago