Motor resists rotation when unpowered

Possible causes

General, component-based causes – not a manufacturer-specific statement.

• Burnt/loose phase connector
• Damaged phase cable
• Winding short or open circuit
• Controller power stage (MOSFET) fault

Safe test steps

• Battery disconnected, controller unplugged: compare A–B, B–C, C–A resistance.
• Does the motor resist rotation even with the controller unplugged?
• Discoloured or melted connectors.

Workshop reference values

• The three phase resistances should be close (typically ≤ 10 % apart); absolute value is motor-specific, often < 1 Ω.

Repair approach

• Replace connector/cable; for winding damage replace or professionally rewind the motor.
• For MOSFET faults repair/replace the controller.

Tools needed

• Digital multimeter (CAT III, fused inputs)
• Milliohm meter (4-wire) – for low resistances
• Basic hand tools, insulated screwdrivers