Starter Controls - NIPPONDENSO: Description

The starter solenoid is an electromagnetic switch, activating a plunger by means of a "pull-in" coil and a "hold-in" coil. The plunger is pulled in, which engages the starter, and then is held in, while the engine starts. When the hold-in coil is activated the pull-in coil is short circuited and only the hold-in coil remains effective. When the current flow to the starter is stopped, the hold-in force is lost and the plunger returns to its rest position.