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#99160 02/07/2007 4:12 PM | Joined: Jun 2005 Posts: 321 Shop Shark | | Shop Shark Joined: Jun 2005 Posts: 321 | the generator saga continues. after 2 months of trouble free operation, last night as i was driving home, the armature fried. for those who might not be familiar with my dilema, back in december i had a charging problem with my 1950 3/4 ton pickup. a diagnosis of the system determined that a new voltage regulator was in order. while waiting for the part to come in i decided to have the generator checked out. everything looked good, put it all back together, polarized the generator and i was off...until i fried the armature. new armature purchased, new ground wire from regulator to generator and i was off again...until i fried the armature. while waiting for another armature to come i replaced the battery and decided to put an old armature from a donor generator in to see if it even worked. it did work. until last night.
o.k. now it appears i'm back to square one and still have no idea why this keeps happening.
i want to stay with the original 6 volt system but i need some input from you guys! where is the problem in this charging system??? | | |
#99161 02/07/2007 5:12 PM | Joined: Jul 2004 Posts: 5,708 'Bolter | | 'Bolter Joined: Jul 2004 Posts: 5,708 | p.j.,
Sorry to hear about the ongoing problems. When you say 'fried the armature', do you mean it actually threw solder? If the band was on the generator, this would have 'shrapnel' blown all over it.
I have little knowledge of these generators, but everything I read says this is a sure sign the unit is producing tons of heat from excessive output.
I agree with you...the new regulator should have solved this problem, and throwing in a fresh battery really should have done it. If your ammeter never shows a massive charge, I wonder if the guilty party could another sticking cutout relay. I think this would start cooking the generator as it tried to 'motor' it, but would probably show itself as a dead for dying battery.
It seems that any wiring issue that put the generator into full output and subsequent failure would be apparent on your ammeter.
Did the springs in the brush holders seem plenty strong..these weren't changed while the armature was.
Stuart | | |
#99162 02/07/2007 10:04 PM | Joined: Mar 2005 Posts: 1,029 Member | | Member Joined: Mar 2005 Posts: 1,029 | Does your ammeter always stay in the high charge mode off-idle? You will fry generator if the field is permanently grounded. The only ground to the generator should be through the case. | | |
#99163 02/07/2007 10:51 PM | Joined: Jun 2005 Posts: 321 Shop Shark | | Shop Shark Joined: Jun 2005 Posts: 321 | atomarc,
yeah it threw the solder. all three times. i'm inclined to think it's the regulator too but i've had two different ones on the truck and both of them fried the armature. "motoring" it appears to be the problem but it must happen fast. yesterday it worked for most of the day and then "bam!" no charge.
now i don't know if the needle on the ammeter pegged when this happened but i didn't notice any surge.
springs on the brushes are good and hold the new brushes nicely in contact with the commutator surface.
baldy,
the ammeter ran just the way it was supposed to. at idle it would float just under 0 and then as the engine would rev up the charge would climb a little and then level off. honestly in the last month it's probably the best the charging system has worked since i've owned the truck...well until last night.
can have a new armature wound up in about a week for $50.00 or have my old one rewound in two weeks for about $90.00. have a contact here that may have another old one sitting on a shelf that i could try.
any other thoughts? | | |
#99164 02/07/2007 11:22 PM | Joined: Jul 2000 Posts: 580 'Bolter | | 'Bolter Joined: Jul 2000 Posts: 580 | A post today on the old-chevy-trucks maillist from Nate Hall might be of some help I forgot to mention that _before_ you try to adjust anything in the regulator , disconnect the battery ground cable and draw some clean , white lint free paper through each and every points in the V.R.
untill the paper comes out clean ~ there should be some black crud deposited on the paer the first pull or two .
8 volt batteries were 4 cell 6 volt bateries that gave Eastern cars an edge in cold weather starting , they really did work O.K. , I don't like to set up the V.R. to 8 ~ 9 volts as this consumes light bulbs faster , a properly adjusted 6 volt system puts out 7.2 ~ 7.5 VDC once the battery reaches full charge and that's more than pleny to crank up an old 6 volts car with an 8 volt batery , in january or February in new Hampshire when I were a laddie .
Your 12 volt generator should be adjusted to 14.5 VDC , no more .
Lastly , DO NOT " polarize " the charging system unless it stops charging ! the field current provided when you turn on the ignition key should do it automatically .
I've seen more brandy new gennies and V.R.'s ruined by " polarizing "
than anything else ~ if you simply _must_ do this , it only takes a millisecond of touching the jumper wire , you'll maybe see a tiny spark and it's good ~ no arc welding ! . big sparks in the charging system at any time is bad , _VERY_BAD_ .
Have fun and don't be surprised if you let the <magic> smoke out of the gennie...
-Nate Nate is a stovebolt member but I don't know how ofter he visits these days. | | |
#99165 02/08/2007 1:55 AM | Joined: Jun 2005 Posts: 321 Shop Shark | | Shop Shark Joined: Jun 2005 Posts: 321 | thanks for the quote laroke. although it may all be for naught.
late this afternoon i crawled under the truck, took the generator off in preperation for replacing the armature. once i had it on the bench i broke it down and discovered that the spring holding one of the brushes had slipped out of the hole and as a result the contact became intermitant at best. procured a new (nos) spring from my donor generator, put it all back together, fired up the truck and lo and behold! it worked!
what is they say...we're only as strong as our weakest part.
thanks guys for your input. this is such an amazing site to be a part of if for no other reason than to commiserate about what confronts us on a daily basis as an owner of one of these great old trucks. | | |
#99166 02/09/2007 2:24 PM | Joined: Mar 2006 Posts: 483 Shop Shark | | Shop Shark Joined: Mar 2006 Posts: 483 | When mine threw solder a field wire was grounded to the case. | | |
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