3 Phase Dol Digital Auto Switch Preventer With Phase Sequence And Single Phase Protection - Application: Agriculture Motor Starter

ADigital Auto Switch Preventerautomatically:

• Detectsphase failure,phase reversal, orlow/high voltageconditions.

• Ensures that connected3-phase motors, pumps, or equipmentreceive correct phase sequence and healthy voltage.

• Prevents operation under unsafe conditions (which can burn motors or cause malfunction).

• In some models,automatically switches between main and backup power sources (Mains/Generator)

Heres how it works step-by-step:

• The preventer continuously monitors all three phases:R (Red),Y (Yellow), andB (Blue).

• It usesvoltage sensing circuits(usually with microcontroller or comparator ICs) to check:

  • Presence or absence of each phase.

  • Correct phase sequence (R-Y-B).

  • Voltage level within limits.

• If any of the following occurs:

  • Phase failure(one phase missing)

  • Phase reversal(wrong sequence)

  • Under-voltage or over-voltage

• The circuit immediatelydisconnects the output relay, preventing power from reaching the connected motor/control panel.

• When all conditions are normal:

  • Therelay energizes, allowing supply to pass through to the load (motor, contactor, etc.).

• When fault is detected:

  • Therelay de-energizes, cutting off the load supply.

• Once the fault is cleared (all phases OK, voltage stable), the preventer automatically:

  • Waits for a shortdelay time(e.g., 60 seconds)

  • Thenreconnectsthe supply to the load.