Home » Public Forums » GMCnet » Isolater vs Alternator (My experience)
| Re: Isolater vs Alternator [message #326673 is a reply to message #326660] |
Sun, 03 December 2017 09:01   |
 |
Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma:
|
Senior Member |
|
|
I don't know about all the other versions, but I have a 73 that has some traits that lead me to believe it was a strange build. The alternator is supposed to be 80amp. The machine in that place now (I did not replace it, but it has been serviced) still looks like the 80amp version. But, things have probably been changed.
We were having alternator belt trouble early on. It was so bad that I regularly put on two belts and tied one back because on a '73 the fan blade and the A/C belt both have to come off to get the new belt in where it needs to be. It was not alignment and I could still but a belt with the right back width. But I was not yet on the forum. This went on for too long because I always though I had a fix in. When I was trying to figure out why I was losing belts (yes Gene, they were at specified tension) whenever we dry camped, I finally put my Hall Probe on the alternator cable one morning. I was really expecting to see that the charge profile was wrong (too high a current for too long). Well, even though the machine is supposed to limit at 80, after the cold start and during the time at high idle, that Hall probe, and Fluke 87 set told me that they were witnessing 96 Amperes....
Before you say that can't happen, remember that when this coach was built it was supposed to have an E5000 91R (Grp.27 side terminal) house battery in the right front. That is a roughly 80AH battery. It was at that end of a piece of #10SAE (not AWG) wire. That battery was a 4D when I got the coach and the #10SAE is now #8 (maybe 6) AWG. This makes for a condition that is very different than when what the pictures and old numbers would allow.
That was when I hunted up a dual sheave for that service. Yes, the power steering sheave can slip when very wet, but it is very manageable when it does.
While doing all the boat work I did before the depression shut us down, I was both informed by suppliers and gained some first hand experience (at my own cost) that a 100 Ampere load on a 12V nominal machine is about all any single V-belt can do for very long at all. There are available marine service machine and regulator sets that can be programed to limit the output current. I have installed these, but the cost is a serious issue. They are great for sailboats where upgrading the installed alternator drive is impractical.
Now, what really surprises me, and I am not complaining, is that it seems that the isolator has never been replaced and still functions as it should. I did replace a very few isolators, but I also replaced more than an few Yandina Combiners. Those were both the 50 and 100 size. The contacts would cease to make a solid an dependable connection. Those are the little ones that come with wire leads that you are not supposed to shorten because just like the #10 battery wires in a GMC, those are a current limiter. The larger version Yandinas all have lugs. I saw those very rarely and never had to replace one.
We now have a dual sheave and a pair of GC2s and I put a PD9260 up front to get the house charged when I have to do it with the APU.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
|
|
|
|
Current Time: Fri May 03 20:37:20 CDT 2024
Total time taken to generate the page: 0.01191 seconds
|
GMCforum
Search
Help
Register
Login
Home
