When the ignition switch is closed, the two coil windings (holding coil S-ground and suction coil S-M) are energized. It is worth noting that since the resistance of the suction coil is small, the current passing through it is large. This coil is connected in series with the motor circuit. Under the action of current, the motor will rotate slowly to facilitate the engagement of the pinion and the flywheel.

At the same time, the magnetic field generated in the coil attracts the iron core to push the pinion gear into mesh with the flywheel ring gear. At this time, the large load main contact B is short-circuited by the short-circuit piece, that is, the short-circuit switch is closed, the main circuit of the starter is turned on, the armature winding provides a large starting current from the battery and generates a strong starting torque; The pull coil (SM) is short-circuited due to the same voltage at both ends; the holding coil (S-ground) continuously attracts the iron core to a specified position.

Until the ignition switch is turned off, the holding coil (S-ground) and the suction coil (SM) are powered by the M terminal, and the magnetic field generated by the suction coil (SM) is opposite to that at the time of starting, and the holding coil The magnetic field of (S-ground) is reversed, the force after the action of the two magnetic fields returns the core, and the main contacts B and M are disconnected. The circuit of the DC motor is cut off and decelerated to a stop.