Quote:
Originally Posted by lutronjim
Kinda high jacking tread a little.
Vettevet
Why does most every thing show the sense wire as being heavy gauge?
To me it just serves so the alternator can 'see' the voltage at a point where most of the vehicle is fed from to enable the alternator to raise or lower output to keep it correct.
To me it could be 22 gauge and work fine - alternator needs to just see voltage not power.
Thanks
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The answer is simple.
The sensor wire serves two purposes. It senses the downstream circuit voltage of the system and tells the internal regulator to adjust the current flow to the alternator fields. If the circuit voltage is lower than 13.5 at idle the regulator closes and allows more of the sensing wire current into the alternator and conversely if the voltage is higher than 14.5 the regulator opens and allows less current.
Because it carries more current than the exciter wire, it needs to be a little larger than the exciter wire. The OEM alternators are regulated differently and they are wired differently inside so the wire size wasn't as important. Plus the output is less so the field current doesn't need to be as much.