| Author |
Message |
ScenicruiserFla (209.86.184.212)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 01, 2002 - 1:56 pm: | |
I have a 1955 GH Scenicruiser, positive ground. I've had in the bus shop three times for charging problems. 1st time, lights puslating fixed by replacing wires end on alternator, 2nd time ( after picking the bus and driving 40 miles ). Overcharging the batts causing them to boil over. They replaced the voltage reg. But it's now not charging. When I took it back again and different shop manager said that couldn't of replaced the voltage reg, cause it's pos ground and they don't carry it. I told him, they got the last one off the shelf, he said that was not the right one. They now want to pull the alt and take it to a shop that can work on it and check it out. ( Which of course I'm not gonna let them do, when I can drive it there ). My question is the voltage reg the same for neg and pos ground bus ?
Thanks |
Steve Fessenden (63.27.88.58)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 01, 2002 - 2:45 pm: | |
Maybe they want to check the alternator to be sure they didn't damage it with the wrong regulator. Do they want you to pay for it?
Steve Fessenden |
FAST FRED (209.26.87.116)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 01, 2002 - 2:50 pm: | |
IF your an FMCA member they had a series of articles on how to change over to negative ground.
AS a service they will copy the article and send it to ya , for free.
You might ask them to post it on their web site too.
FAST FRED |
R.C.Bishop (128.123.88.22)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 01, 2002 - 7:01 pm: | |
Steve, if you attempted to send me something thru my email address, I could not open it. I replied to you but JUNO says there is no such address.....either try again or, perhaps you did not send.
RCB |
DrivingMissLazy (65.207.109.60)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 01, 2002 - 7:15 pm: | |
R.C. Did you receive my email a couple of days ago?
Richard |
jmaxwell (66.42.92.250)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 01, 2002 - 9:46 pm: | |
Steve: Ditto to RC's msg. |
Ray C (142.165.92.179)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 01, 2002 - 10:43 pm: | |
Steve your computer has a virus and is sending out messages. I received one as well but my Norton antivirus dealt with it. |
Jayjay (207.30.180.37)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 01, 2002 - 11:15 pm: | |
Since your PD4501 has a generator, you should be able to "polarize" it for either positive or negative ground. Your 'Book' or an old time mechanic will show you how. If it is a Leece-Neville generator, you may have to purchase a regulator that is polarity-specific. HTH Cheers...JJ |
DrivingMissLazy (65.207.109.53)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 02, 2002 - 7:46 am: | |
Back in the early 80's I had a 4104 with positive ground. Changing to negative ground was extremely simple. I simply reconnected the batteries by re-connecting the cable going to the chassis to the negative terminal of the battery and the other cable to the positive terminal of the battery. Flashing the field consisted of using a jumper cord to momentarily connect the positive terminal of the battery to the field connection of the generator and getting a flash (spark).
There were two seleninum rectifiers (old time diodes) in the safety shut down circuit that needed to be reversed for the safety shutdown to work, but since that function had been disabled, I never bothered to make that change.
As I recall, that was all that I had to do. Upon starting the engine, the generator immediately started charging. You might need to flash the field a second time, once the engine is running to get the generator to start charging.
Richard |
Fred Mill (63.28.30.52)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 04, 2002 - 2:28 am: | |
The Scenicruisers were all changed to alternators when the 8v71 engines were installed in the 60's. The regulator IS the same for both pos. and neg. ground, but the diodes in the alternator are different for pos. ground, and the regulator wiring is different for pos. and neg. ground. DO NOT flash the field to repolarize or you may damage the regulator. To change to neg. ground, the instructions for the 4104 apply, but you also need to change the diodes in the alternator, and change some of the regulator wiring. If you need any help with this, contact me directly, I'm in the process of changing over my 4501 this week.
Fred Mill
millfm@earthlink.net |
Red McWilliams (Celtsong) (209.184.1.50)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 10, 2002 - 11:19 pm: | |
After changing to negative ground, how much is involved in changing your entire system over to negative? Such as lights, gages, etc. Sorry, I'm new at this. |
Richard Bowyer (Drivingmisslazy) (65.207.109.124)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 11, 2002 - 9:06 am: | |
Red, not much really, as I recall. It has been 20+ years since I did my 4104.
First, the lights could care less. You will have to do nothing to them.
I really do not remember about the guages. As I recall they were very minimal and if one of them reads backwards, then you would simply reverse the wires on the back of the guage. The speedometer is mechanical, since electronic speedometers were not available in th 50's as I recall.
The safety shut cown circuit contains two selenimum rectifiers. They have probably died from old age by now and they should be replaced with the modern day silicon diode. The electrical connections must be reversed to get this circuit to work properly.
Overall, it is a relatively simple task.
Richard |
Richard Bowyer (Drivingmisslazy) (65.207.109.124)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 11, 2002 - 9:59 am: | |
Red, I just re-read your post and you state the the generator is not charging and you have replaced the regulator. It was not uncommon "in the old days" to have to flash the field anytime you worked on the generator system, or replaced the voltage regulator.
It is easy to do. With the engine running, connect a wire from the hot (negative) teminal of the battery momentarily to the field terminal (small wire) of the generator. If that was the problem, then a flash or two will re-magnatize the field circuit and it will start charging. Caution, do not leave this connection on for more than a few seconds as the generator will be charging at maximum rate. It should arc when you do this and the generator should start charging immediately. If you do not get an arc, then the generator field is probably open and therefore defective.
If this does not solve the problem, remove the field wire coming from the regulator to the generator and leave it unhooked. Now, with the engine running, connect the jumper from the battery to the generator field terminal and leave it connected. At the same time, have a voltmeter connected to the generator output (armature) terminal. The generator should start charging and the output voltage should be significantly higher than the normal voltage. I believe in the neighbourhood of 16+ volts. If the generator does not charge then there is a problem in the generator, and the regulator is probably good.
First thing to check is the brushes. Really, you should have already done this at the very start of the problem, and is the very first thing to check when a generator quits charging.
To check the brushes, lift up the spring holding each brush and make sure they are free to slide up and down in the holder. Many times they are sticky and will not move at all. If not free, spray with electrical cleaner until they are free. Make sure the brushes are long enough to touch the commutator bars when the spring is holding them down. If the spring is touching the metal of the brush holders, the brushes are worn out and need replaced.
Next, check the condition of the rotating commutator bars on the armature. They should be bright and shiny copper. If they are badly burned and pitted, usually caused by worn out brushes, then the generator will have to be removed and the commutator turned down and undercut by a machine shop. NAPA or PepBoys should have the proper lathe to do this. Do not forget that the mica insulation bars, between the copper commutator bars, must be cut down below the surface of the copper.
If the commutator is just black and dirty it can be cleaned with spray electrical cleaner and then burnished by holding a pencil eraser against it (while the engine is running and the armature is turning).
Let us know what you find out.
Richard
BTW, you are really taxing my memory, as I have not done this for 50 years! |
Gene R (12.13.175.93)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 12, 2002 - 9:41 am: | |
Red, In my humble oponion, it is best not to have the motor running when you flash the field curcuit on a "A" type generator. "B" curcuit units require different polairazition Most Delco gens are "A" type. The contacts in the reg should be closed be closed when the engine is running and the chance to weld the points together is pretty great. Most of the time it will work ok but it will do the same thing with the engine off also, with no chance of a point weld. If the points weld and the "B+" wire is hot with the moltor off, the gen will try to act like a starter and try to turn itself. As it can't turn (belts or gears holding it), we have seen some oily units catch fire!!!! Flashing the field with the engine off will reverse the polairity in the pole pieces and cause the gen to recognise the same polairty as the battery. FWIW, I'm done!! Bye!!! Gene R. |
DrivingMissLazy (65.207.109.67)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 13, 2002 - 10:21 am: | |
Do not disagree with you at all. Guess I was just too lazy or didn't know the potential problem in my younger days. LOL
It is important to remember that only a flash is needed.
If the generator is not turning and power is applied to the field for longer periods of time, it can burn up the field windings.
Richard |