Contactor Motor Starter
A motor branch switched by a contactor. The MCB protects the cable, the contactor does the switching, and it breaks live and neutral together so the motor is isolated when the coil drops out.
Components Needed
Text Wiring Path
Live → MCB → Contactor → Motor → Neutral
Schematic
Steps
- 1Place a Live (L) terminal and a Neutral (N) terminal on the canvas.
- 2Place an MCB on the live conductor to protect the cable.
- 3Place a Contactor after the MCB, then a Motor as the load.
- 4Wire Live → MCB → Contactor, and Neutral → Contactor.
- 5Take the contactor's switched live and switched neutral through to the motor.
- 6Press Run, then toggle the contactor or the MCB — either one stops the motor.
Protection and switching are separate jobs: the MCB clears overcurrent while the contactor handles the repeated making and breaking of an inductive load. Switching both conductors means the motor is never left sitting on a live rail when the contactor drops out.
Motor circuits draw a heavy starting surge and store energy in their windings. Size protection for the surge, provide a lockable local isolator, and treat the terminals as live until the supply is isolated and proved dead.
Terms used here
Defined in the glossary — each one opens at its own entry.
Now wire it for real.
Build this circuit in the browser, inject a fault, and watch the protection respond.