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Author Topic: GM PD4107 12V DN50 Regulator  (Read 671 times)
gus
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« on: November 07, 2013, 02:47:00 PM »

I had an interesting experience today with the above.

I tried attaching an auto noise suppressing condenser to the VR field to see if that would stop the "nervous" VM needle syndrome. I'm really tired of bright and not-so-bright lights! It didn't!

In the process I accidentally grounded the pos side of the VR which killed ALL output.

I dragged out the old used VR that came with the bus to see if it worked, it didn't. So, I momentarily hit the Field terminal with 12v to make sure the gen was good. It was. Then the funny thing, the new VR started working just fine.

I quickly figured out that I had just flashed the VR field which made it work! Never heard of flashing a VR but it makes sense. I presume that this flashed the gen field also but not sure of this? Maybe it was just that I had flashed the two together that made it work?

This bus was never Pos ground.

The manual says to put 12V on the gen field terminal to make sure the gen is good but it says nothing about doing this via the VR F terminal. As far as I can see it is electrically the same thing?

So if that worked I thought maybe I could do the same thing to the installed one. Hooked if up again and it worked fine even without flashing, even the needle settled down? Go figure.

Can any of you electrical types tell me what happened?
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PD4107-152
PD4104-1274
Ash Flat, AR
RJ
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« Reply #1 on: November 07, 2013, 07:41:55 PM »

Gus -

Sounds to me like you were one of the lucky few who have managed to put the smoke back IN to an electrical device.

Most of the time when we let the smoke out, it's dead & gone.

 Grin
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RJ Long
PD4106-2784 No More
Fresno CA
luvrbus
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« Reply #2 on: November 08, 2013, 05:15:13 AM »

On a Niehoff that is the way the over charge (OVCO) circuit is reset I never knew the original Delco VR had one
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Live each day like it was your last,one day it will be
jmsokol
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« Reply #3 on: November 08, 2013, 11:09:00 AM »

Gus -
Sounds to me like you were one of the lucky few who have managed to put the smoke back IN to an electrical device. Most of the time when we let the smoke out, it's dead & gone. Grin

Here's a smoke recharge kit you can get for British sports cars. Of course, your mileage will vary:  Wink

http://www3.telus.net/bc_triumph_registry/smoke.htm

Mike Sokol
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Oonrahnjay
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« Reply #4 on: November 08, 2013, 11:48:22 AM »

  Here's a smoke recharge kit you can get for British sports cars. Of course, your mileage will vary:  Wink

http://www3.telus.net/bc_triumph_registry/smoke.htm

Mike Sokol 


     Oh, I am *SO* there!  (Although I must admit that I've had fewer smoke instances than I thought that I would.   Notice, I didn't use the word "none".)
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Bruce H; Wallace (near Wilmington) NC
1976 Daimler (British) Double-Decker Bus; 34' long
6-cyl, 4-stroke, Leyland O-680 engine

(New Email -- brucebearnc@ (theGoogle gmail place) .com)
bevans6
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« Reply #5 on: November 08, 2013, 02:02:11 PM »

Just random thoughts - if the voltage regulator is solid state, it's basically a transistorized switch that turns the alternator field on and off.  On until the output exceeds the reference voltage (from the battery) by a set amount, then off again and repeat, very quickly.  There is nothing in particular to reset in the VR, it's just an output.  The field coil is energized by the 12V to full on, if you did that when the alternator was running you would get full output from it.  If you do it when the alternator is off you can re-energize residual magnetism and get it to start again.  Alternators are kind of black magic to me, I hate that I don't fully understand exactly how they work.

Brian
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1980 MCI MC-5C, 8V-71T from a M-110 self propelled howitzer
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Vintage race cars -
1978 Lola T440 Formula Ford
1972 NTM MK-4 B/SR
gus
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« Reply #6 on: November 08, 2013, 03:42:11 PM »

Today I started it up again and it has steadied down to about 0.01V variance, I can sure live with that, best it has ever been since I got the bus! It was 2-4V before.

When I momentarily hit the Field terminal with 12v it was only to make sure the gen was good but I think this caused the VR field voltage to settle down. The manual says to do this but I think it says with the VR disconnected! I'm too lazy to look it up right now.

The VR, I think, is a combination of diodes and old mechanical stuff. It is about the size of a brick and a bit heavier so I doubt it is all solid state. I took AC theory in three different schools and I still don't understand it!!

There is a solenoid in the field circuit so it appears the VR kicks the solenoid which applies batt voltage to the gen field. That solenoid used to click on and off so often it drove me nuts. Same for the solenoid which allows the original heat/AC fan motor to get voltage. I finally put a switch on it because it is right next to the driver and rhat sure can't be good for solenoids.

The manual says to NEVER ground any VR terminals. Kind of weird since one of the three is ground? Anyway, I'm really happy since the purpose of my method was to stop the nervous VM needle even though I did do it by dumb luck!

I have a '63 TR4 so I probably need the smoke removal kit!
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PD4107-152
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Ash Flat, AR
Ed Hackenbruch
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« Reply #7 on: November 08, 2013, 06:14:18 PM »

I have a "slightly modified"  '62 TR 4    Grin
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1968 MCI 5A with 8V71 and Allison MT644 transmission.  Western USA
gus
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« Reply #8 on: November 12, 2013, 03:43:36 PM »

Update; I drove ten miles on a 1000 mi trip and it failed again.

Went back home, messed around, found I could jump batt voltage from a nearby lighting buss to the VR Pos terminal and it produced a nice steady charge.

Now 500 mi into the trip with the jumper in place and all is well!
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PD4107-152
PD4104-1274
Ash Flat, AR
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