In-Rush Current Reduction Relay - Operation

OPERATION

In-Rush Current Reduction Relay.
Within the ICR relay, prior to the starter motor solenoid's contact closure, the shorting bar opens contacts, thus routing the starter motor current through a resistor bar (10 mOhm for V6 Pentastar). The increase in series resistance reduces/eliminates the initial current spike (or, inrush current) and reduces the consequent voltage drop. After a set time (185 msec), the power to the ICR relay is cut, the shorting bar closes the contacts, removing the resistor bar from the circuit and restoring full power to the starter motor. At this point, there is a rebound of the current surge and subsequent drop in voltage; however, neither is as intense as they would be would be without initial jump in resistance.