How does a Three-Phase Motor Control Circuit Work?

How does a Three-Phase Motor Control Circuit Work?

A three-phase motor circuit consists of two major components:

  • Power circuit (380 V) &
  • Control circuit (220 V).

The power circuit comprises

  • Circuit breaker,
  • Thermal overload relay,
  • Contactor &
  • Motor

which supplies and protects the motor.

The control circuit manages the start/stop operation with an MCB and an On/Off switch, safely energizing the contactor coil.

This configuration enables a low-voltage control circuit to reliably operate a high-voltage motor, providing both protection and efficiency.

Circuit Breaker (Power Circuit – 380V)

The circuit breaker (380V) protects the motor from short circuits & overcurrent failures.

Thermal Overload Relay

Prevents motor overheating by cutting power during overload conditions.

Contactor

An electromagnetic switch that operates the motor remotely via the control circuit.

3-Phase Motor

The primary load that transforms electrical energy to mechanical motion.

MCB (Control Circuit - 220V)

MCB (Control Circuit - 220V) protects the control circuit from short circuits (or) malfunctions.

Start-Stop Switch

Manually control the contactor coil to start or stop the motor.

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