WesBrooks Posted June 5, 2017 Share Posted June 5, 2017 Hi All, First things first, the field input to the alternator from the Alternator warning light. How much current does this sink? Can it be connected directly to an ignition switched live, or does the bulb act as a current limiter? Secondly I'm interested to know how you would go about completely shutting off an auxiliary alternator so that it doesn't add excess drag on the engine? I've heard people talk about cutting the supply to the field, but some also mention that some alternators self energise at over a certain rpm? It is suggested that just cutting the feed could cause a voltage spike that has the potential to damage internals of the alternator such as the rectifier section. Thanks for any input you can offer! Quote Link to comment Share on other sites More sharing options...
CharlieB Posted June 5, 2017 Share Posted June 5, 2017 Cutting the field wiring is fine, I do this on my boat to reduce RF interference sometimes. The only problem on some alternators is that the brushes are integral with the regulator, so difficult to break the wiring for a switch. Some old Lucas alternators had the option of a brush pack with remote regulator pack. I suppose the only other option is maybe to modify an aircon clutch or similar to fit. Quote Link to comment Share on other sites More sharing options...
CharlieB Posted June 5, 2017 Share Posted June 5, 2017 When testing an alternator, it's ok to put a straight 12v feed onto the warning light wire, but I don't think it would be good for the reg. to apply it for too long without the motor running. Usual wattage is about 2W. Once running, there is obviously no current flow. Quote Link to comment Share on other sites More sharing options...
WesBrooks Posted June 5, 2017 Author Share Posted June 5, 2017 Cheers, that gives me a bit more of an idea on what is going on! Quote Link to comment Share on other sites More sharing options...
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