The components of a Electric Brake System consist of backing plate which houses the important braking components such as magnets, magnet lever arm, brake shoes, springs and the brake drum.
The backing plate is fixed to the end of the axle and wired to the 12 volt plug of the trailer which connects to the car. When an electrical current is provided from the car the magnet is energised and tries to stick to the face of the brake drum, due to rotation of the wheel the magnet moves the lever arm in the same directing. This movement forces the primary brake shoe against the drum. The force of the primary shoes in turn pushes the secondary brake shoes against the drum to complete the braking sequence.
The amount of braking effort will depend upon the level of current flowing to the magnet and this is determined by the brake controller fitted in the vehicle.