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Isoloter ? Alternator ? Regulator ?

April 10, 2014, 05:41:08 pm

More on my ' Inverter Question ' post a few days ago.
2 day & 2 nights using inverter only.
75 miles home, monitor shows 11.8 v on coach battries.
Plugged in to shore power, coach battries back up around 14 v.
* Checking battery cables.
Middle (alt.) terminal on isolator - cable end & 3" of insulation burnt off.
All other cables look ok and all battries seem to be ok.
Per ?'s post the other day.  Contunity check between center (alt) post and out side post good.
Will conduct from center to outside but not from outside to center.
Finally saw that the exciter wire on right outside post (eng battries) was also burnt off.
***Alternator is showing 26.30 volts at the end of the burnt alt. cable (not connected to anything) with engine at idle.
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The Question:  Did or does the burnt off exciter wire have any thing to do with the 26.30 volts   Or am I just grabbing at straws ?
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We have a very good alternator shop.  Is it just a regulator problem ?  I know it's charging good !
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PS.  An old 5.9 Cummings doesn't use much DC voltage while driving in the day time !
Engine battries were still at 12.4 volts.
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As always.......Thanks for the Help.........~JL~......

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Re: Isoloter ? Alternator ? Regulator ?

Reply #1 – April 10, 2014, 05:55:06 pm

Oh yea,  I have searched and read the previous post abut Isolators and could not find my exact problem.
~JL~

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Re: Isoloter ? Alternator ? Regulator ?

Reply #2 – April 10, 2014, 05:58:24 pm

Johnnie,

Is the burned wire an exciter wire or SENSE wire.  If sense wire, absolutely it can cause bazaar voltages, as the alternator is being told that voltage is way low.

Best advice, repair/replace broken or loose wires and connections and take new readings.  Not fair to expect any system to work properly if the wires are not in good shape.

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Re: Isoloter ? Alternator ? Regulator ?

Reply #3 – April 10, 2014, 06:52:33 pm

Thanks Brett,
I'm 'assuming' and I know what that leads too.
That's it's the exciter wire,  I didn't find a 'sense' wire on the wiring schematic.
I will study it again.  I'm not very good with schematics.
I should have taken the cables off the isolator post , maybe that would tell me how many are burnt off.
Thanks...........~JL~  (will find out more tomorrow)

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