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OEM Voltage Regulator operation

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  • simplyconnected
    • May 26 2009
    • 8723

    OEM Voltage Regulator operation

    I promised johng I would write up the sequence of how our original voltage regulators work.

    The most important part to check is the current path through the resistors. Here's why...

    When we first turn the key, the voltage regulator is disconnected from the battery. That means the Cutout Relay must be energized strictly by generator power.

    As the generator starts to produce power, the armature (A) feeds the generator's field (F) through normally closed contacts. The coils and resistor (R2) are connected to each other via ground. Without the resistors, current for the cutout relay coil would not have a completed path. Therefore it would never connect the battery to the generator.

    Check this out and give the sequence lots of time to better understand each phase of operation:

    So why is this so important? Troubleshooting a 'dead' voltage regulator is simple if you understand the current paths, especially while the cutout relay is NOT energized.

    Look at the normally closed contacts from the overcurrent and overvoltage relays. If either are dirty or open, the field only gets enough current passing through the top resistor to sustain the cutout relay coil IF it's already closed. It's not enough to initially pull the cutout relay in.

    Battery charging can only happen when the cutout relay is energized. All the generator's power goes through this one contact. The other two control the field.

    I'm sure some of you will have questions. - Dave
    My latest project:
    CLICK HERE to see my custom hydraulic roller 390 FE build.

    "We've got to pause and ask ourselves: How much clean air do we need?"
    --Lee Iacocca

    From: Royal Oak, Michigan