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From: (no name) (no email)
Date: Fri Dec 03 2004 - 13:44:05 EST
In a message dated 11/30/2004 9:48:18 PM Eastern Standard Time,
writes:
My new (to me ) trawler has a Cummins engine. It uses a Delco 19si 105 amp
alternator
with internal regulation. I would like to convert it to external
regulation. Can anyone direct me on how
to disconnect the internal regulator and bring the field wire outside the
case?
Joe Urban
Ideally, one has a standard automotive internally regulated alternator
dedicated to topping up the starting battery, and a big honkin' 200 amp alternator
with a 3-stage external regulator to top up the house batteries.
However, if you want to externally regulate an internally regulated
alternator it can easily be done. I presume you have no gasoline in the engine room.
After opening the alternator case, examine the two brushes contacting the two
slip rings for supplying current for the rotating field.
One will either go to ground or +12VDC, the other to the regulator circuit.
You need to change things so that one brush goes to ground and the other to
your external regulator. You can simply cut any conductors and solder wires
onto the brush side of the cut. It helps if you tin (coat with solder) both the
wires and the spot you solder them to before mating them up. Lead the wires
out of the alternator case via a safe route and connect them to ground and your
regulator. Polarity doesn't count.
It can be tricky holding the brushes back to close the case. Some brush
holders have holes drilled in them to allow you to hold the brushes back by
inserting a piece of wire through the holes and pulling out the wires after closing
the case. I have also used a thread looped around the brush and back outside
the case, cutting the thread and withdrawing it after closing the case.
It would be cool if you completely disconnect the internal regulator from all
power so that if there was some failure there it will not affect your
alternator.
When the alternator dies, replace it with an externally regulated one. I
have a Chrysler type.
Take great care to never operate an alternator with no load, doing so will
allow the output voltage to spike so high it will blow the alternator's
rectifier pack in a heartbeat.
Norm
S/V Bandersnatch
Lying St Augustine FL
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