question

andy avatar image
andy asked

Argo FET Energize Current

On the many Argo FET isolators I have installed I fit a 5A fuse on the Energize input. On a recent vessel I have done the same and the fuse always blows when the the engine starts. If the fuse is removed during starting it can be replaced when the engine is running and charging commences. The alternator B+ seems to be open circuit until it is energized. The field input also measures open whereas most alternators show a low resistance.

What fuse should be placed in the Energize line?

What is a typical current expected on the Energize input?

DO modern alternators require a larger start up current?

Argo FET Diode
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2 Answers
Paul B avatar image
Paul B answered ·

as a guess you maybe getting a reverse current from the calapsing alternator rotar field when the engine starts as sometimes this is turned off when start is selected, so put a blocking diode inline with the fuse to stop the reverse current. (If its that).



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Elimac avatar image
Elimac answered ·

Also make sure you use a "SLOW" blow fuse, not a fast one.

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