SYSTEM / Electrical System SERGE VOLTAGE PREVENTION CIRCUIT 1. When the engine is stopped (key switch: OFF), current from key switch terminal M is discon- nected and the battery relay is turned OFF. 2. The engine continues to rotate due to inertia force just after the key switch is turned OFF so that the alternator continues to generate electric- ity. 3. As the generating current cannot flow to the bat- tery, surge voltage arises in the circuit and fail- ures of the electronic components, such as the controller, possibly cause. In order to prevent the occurrence of surge voltage, the surge voltage prevention circuit is provided. 4.
When the alternator is generating electricity, gen- erating current from alternator terminal L flows to monitor unit terminal #C7. The monitor unit con- nects terminal #A12 to ground. 5. Current flows through the load damp relay excit- ing circuit and the load damp relay is turned ON. 6. Accordingly, even if the key switch is turned OFF while the engine is rotating, battery current con- tinues to excite the battery relay through the load damp relay. 7. When the alternator stops generating, the battery relay is turned OFF. T2-5-14