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Topic: Reversed alternator connections.  (Read 872 times) previous topic - next topic

Reversed alternator connections.

While having some work done at a Fortravel (w/ Motorcade discount) recommended shop it seems they installed an alternator and hooked up the connections " backwards".  I was told that they had probably " blown" the voltage regulator part of it. Without knowing just which wires exactly were reversed, I'm wondering what else could have been damaged.

 The shop has a very good reputation and has several high end coaches in their bays with a variety of things being done to them. I do trust them to do exactly what's necessary for repairs. They have also completed a cooling system flush w/ new long life coolant , replaced the hour meter on the generator and replaced an aging engine battery ( part of the effort to solv the charging problem).

 The problem happened on Friday afternoon, so a new alternator was ordered and could be installed as soon as Monday or could take as long as Wednesday we were told.

  Has anybody else ever done anything like this ?    Thanks for any imput.
Robert and Susan
 1995 36' 280 WTBI 8.3 3060r
 1200 watts on the roof, 720 Ah of lithium's
 Build # 4637. Motorcade # 17599
        FMCA  # 451505
        18  Wrangler JLUR

Re: Reversed alternator connections.

Reply #1 –
The only wires they could have crossed are the small ones to the voltage regulator, don't see how it could cause any coach damage.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Reversed alternator connections.

Reply #2 –
Quote from: craneman –
The only wires they could have crossed are the small ones to the voltage regulator, don't see how it could cause any coach damage.


That's great to hear !!  Thanks much.

 Gotta love this forum for quick answers.
Robert and Susan
 1995 36' 280 WTBI 8.3 3060r
 1200 watts on the roof, 720 Ah of lithium's
 Build # 4637. Motorcade # 17599
        FMCA  # 451505
        18  Wrangler JLUR

Re: Reversed alternator connections.

Reply #3 –
Hi Bob,
 Did they fry the connections on the alternator? When I burnt mine out ( don't ask ) it was quite a while later I found that the isolator had taken some heat and so I bought one from O'Reillys and replaced that also. I hope this is not the case for yours.
Geoffh
Geoff & Pat Haygarth
1994 U240 SBI GV 36ft Cat 3116, Allison 6 speed
 Build #4448
2015 Jeep Wrangler Sport

Re: Reversed alternator connections.

Reply #4 –
Reversed connections probably fried the diodes.  Depends on what Alternator you have,  GM or Delco types are easily fried this way.
Gary B

Re: Reversed alternator connections.

Reply #5 –
Geoff.
 What was the symptom that indicated the isolated was damaged. Not sure what to look for.

Gary.
  We will pick up the coach today. All I know so far is that the alternator that was in it was not a Leece Neville (sp) and the new one came from NAPA. I was told that the one they fried on Friday had an extra terminal. Seems the installer wasn't sure about the connections obviously. Monday they had " a fresh set of eyes" on the project and " working fine now".

    ARGH  Motor homes are so much different than a convential vehicle in the parts and repair aspect and I'm still trying to get my head around it.
Robert and Susan
 1995 36' 280 WTBI 8.3 3060r
 1200 watts on the roof, 720 Ah of lithium's
 Build # 4637. Motorcade # 17599
        FMCA  # 451505
        18  Wrangler JLUR

Re: Reversed alternator connections.

Reply #6 –
Bob, VERY IMPORTANT that the shop understand that FT's have FOUR wire EXTERNALLY excited systems.  If they try to install another type it will not work.  Do a search here and read all you can about the alternator systems on FT's.  Most shops do not have a clue about four wire systems and isolators.  Good luck with it.  I do not recall when I looked at that coach that it had anything other than a Leece Neville or a OEM alternator.
Gary B

Re: Reversed alternator connections.

Reply #7 –
Thats what I'm trying to determine with my post,my alternator was working great with 3 wires,are you counting the black wire
from the voltage reg to the terminal on the left as the 4th wire,on my coach the thats how it was wired but the so called left
terminal did not have any other wire going to it,just the one from the regulator.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Reversed alternator connections.

Reply #8 –
Hi Bob,
 After having the alternator rebuilt, I did have problems with the coach batteries losing their charge, going through different possibilities with my brother, John would suggest I check this then that and one time I inspected the isolator and saw that it had been subjected to a power surge, which had to have been the occasion  I fried my alternator. ( see photo, it shows the discolouration from excessive heat ). I have replaced the unit and things are good again.
wishing you good luck with your repairs,
GeoffH
Geoff & Pat Haygarth
1994 U240 SBI GV 36ft Cat 3116, Allison 6 speed
 Build #4448
2015 Jeep Wrangler Sport
 

Re: Reversed alternator connections.

Reply #9 –
Bob
Was your alternator a Powerline 24HD /  190 amp?
Justin & Cathy Byrd
1995 U280 "Old Faithful"
36' Build #4673
C8.3 Cummins
Allison MD3060R 6 speed - retarder
Powertech 10KW  4cyl Kubota