Three-Phase direct Online (DOL) Motor Starter Circuit Diagram

This electrical diagram illustrates a complete Direct Online (DOL) starter system for a three-phase induction motor. The drawing includes both power and control circuits with comprehensive terminal connections. The power circuit features a main MCCB (Molded Case Circuit Breaker) connected to the three-phase supply (L1, L2, L3, N), followed by an MCB, overload protection (-OL), and the main contactor (MAIN-MC1) that feeds the three-phase motor terminals (U1, V1, W1). The control circuit incorporates start/stop push buttons, overload protection contacts, indicator lamps for running and stopped states, and a current transformer (-CT) connected to an ammeter for monitoring motor current draw. The diagram uses standard IEC electrical symbols and includes terminal numbering (03-08) for easy panel wiring and troubleshooting. This starter configuration provides basic motor protection against overloads while allowing simple on/off control; notably, it lacks soft-start capabilities which makes it suitable for motors where high starting torque is acceptable.