Alternator and voltage regulator question?

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Diamond Dave - 13 Mar 2006 03:09 GMT

On a '94 DAK 3.7ltr AT, AC cc is the alternator's out put controlled by the
computer or is there an independent voltage regulator? Also: my truck came
with the 90A alternator, can I upgrade to the 120A HD alternator without causing
problems in whatever acts as the voltage regulator?

TIA.
Bill

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Gary Glaenzer - 13 Mar 2006 05:01 GMT

1) internal to the engine comp
2) no idea

> On a '94 DAK 3.7ltr AT, AC cc is the alternator's out put controlled by the
> computer or is there an independent voltage regulator? Also: my truck came
[quoted text clipped - 3 lines]
> TIA.
> Bill

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John Kunkel - 13 Mar 2006 20:35 GMT

> On a '94 DAK 3.7ltr AT, AC cc is the alternator's out put controlled by
> the
> computer or is there an independent voltage regulator? Also: my truck came
> with the 90A alternator, can I upgrade to the 120A HD alternator without
> causing
> problems in whatever acts as the voltage regulator?

The regulator won't care what amp alternator is installed, it only deals
with regulating the voltage.

Be sure your wires are properly sized for the added current.

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TBone - 13 Mar 2006 22:45 GMT

Yea, but it does it by controlling the current to the field windings. If
this new alternators field winding current exceeds the capabilities of the
computer internal regulator, it could damage it.

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>
> > On a '94 DAK 3.7ltr AT, AC cc is the alternator's out put controlled by
[quoted text clipped - 8 lines]
>
> Be sure your wires are properly sized for the added current.

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Nirodac - 14 Mar 2006 02:25 GMT

Yea, I was thinking the same thing.
If your going to be pulling more current out of the alternator, you'll need
more current on the field winding, to supply it.

If you truly are going to be drawing more current, you may want to consider
an external regulator.

> Yea, but it does it by controlling the current to the field windings. If
> this new alternators field winding current exceeds the capabilities of the
[quoted text clipped - 15 lines]
> >
> > Be sure your wires are properly sized for the added current.

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Diamond Dave - 14 Mar 2006 03:00 GMT

>Yea, but it does it by controlling the current to the field windings. If
>this new alternators field winding current exceeds the capabilities of the
>computer internal regulator, it could damage it.

Is there a different CPU for the vehicles with the 120A alternator and opposed
to the ones with the 90A? Have you ever heard of defining which CPU to get by
what alternator you have? I'm not going with a monster aftermarket alternator,
just the bigger 120A one that was optional on this truck.

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TBone - 14 Mar 2006 04:30 GMT

> >Yea, but it does it by controlling the current to the field windings. If
> >this new alternators field winding current exceeds the capabilities of the
[quoted text clipped - 4 lines]
> what alternator you have? I'm not going with a monster aftermarket alternator,
> just the bigger 120A one that was optional on this truck.

I have no idea if a different computer was used for the 120A alternator but
if it was an option, probably not. There may however been other changes
such as the wiring harness connecting the alternator to the vehicle. I
guess the first question you need to ask is why you want or need the 120A to
begin with.

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John Kunkel - 14 Mar 2006 20:54 GMT

> Yea, but it does it by controlling the current to the field windings. If
> this new alternators field winding current exceeds the capabilities of the
> computer internal regulator, it could damage it.

The computer supplies a variable ground for one side of the field, the
current in the field doesn't rise with the alternator's output; several
different alternator amp ratings are controlled by the same computer.

>> > On a '94 DAK 3.7ltr AT, AC cc is the alternator's out put controlled by
>> > the
[quoted text clipped - 9 lines]
>>
>> Be sure your wires are properly sized for the added current.

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