Starter Solenoid has two functions:
1. To control the start circuit on / off (Connect the battery to the starter)
2. Drive the starter pinion engaging in the flywheel ring gear.
Function 1
When you turn on the ignition switch the starter circuit is turned on, the electric current flows to the Starter Solenoid and creates a electromagnetic force.
The electromagnetic force of the solenoid switch, sucks the movable iron core in the Starter Solenoid to contact the two terminals. One of which connect to the positive pole of the battery and the other terminal to the starter.
Function 2
The electric current divides into two streams flowing through the Starter Solenoid:
A ). A stream flow through the sucking coil, generating a magnetic force to sucks the movable iron core. And, move the fork backward so that the starter pinion can engage the engine flywheel.
B). The another stream flows through the holding coil, creating a magnetic force. And, keeps the core in the post-pulling position until the starting complete.
