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Smoking Dynamo Voltage Regulator


Gary Flinn
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Can anyone offer advice on why the Voltage Regulator on my car is smoking!ūüėĮ

I've recently had charging troubles which I assumed was the Dynamo, I had the ignition light on and discharge shown on the Ammeter under normal running conditions

After inspecting the Dynamo and finding one of the brushes completely worn down, the other one very similar and the commutator very worn, I have replaced the brushes and cleaned up the Commutator with fine Glass paper and re-cut the best I can the Mica sections, the Dynamo now seems to work again.

After joining out the Armature and field connections with a link wire and then connecting one of the Link Wire Terminals to positive on a battery and a link wire to the Earth terminal on the Battery and the dynamo casing, the pulley rotated.

After refitting to the car, I left the link wire on and when¬†putting¬†a volt meter connected to earth and one end of the link wire, I got a reading of just over 14 Volts¬†at tick over which I have read on the Net is correctūüôā.

Now with all the wires re-connected correctly (I've double checked this) the Ignition light is now on at the first position of the key and goes out when the car is started and revved, however the Ammeter show a charge of about 20 to 25 Amps initially and this doesn't drop.

Even if I switch the lights, heater fan and wipers on it still shows a charge of around 5-10 Amps at tick-over and the Regulator box starts to smoke, obviously I've only ran the car for twenty seconds or so till I saw the smoke and then switched off and disconnected the battery immediately, although there is no smoke when the engine is not running.

Can any Car Electrical guru's offer any advice, I'm beginning to think it may be some sort of fault inside the Dynamo as I cannot see any wiring faults between the Dynamo and regulator  

PS - I have noticed on the back of the Regulator one of the Resistors was getting very hot (The one connected to the Cut-out coil) and presumably it was this that was smoking!!

The car is not a Triumph (Its a Sunbeam) the Dynamo is an Original Auto-lite item and the Voltage Regulator a replacement Motorcraft one. 

Can anyone give me a clue whats wrong?  

 

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A replacement (N.O.S.) Control box is also smoking so that's what made me think it was a possible Dynamo Fault?

The car is a Sunbeam Tiger so the Dynamo & Control box are Ford (Autolite) sourced parts.

I do have a secondhand Dynamo so was going to test this and replace and see if the same thing happens?

 

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.

I had a smoking regulator on my Citroen, and the fault was a tiny metallic flake had become dislodge from wherever and found itself in the open contacts of the regulator. (see photo).  The result was a direct short.  Once this tiny speck was removed all was fine. 

P1230190.thumb.JPG.d93e2a287313eeea5b273e74c02d4852.JPG

I have no idea where that particle came from,  as inside its closed and sealed case - the regulator was pretty clean and seemingly previously unopened.  But I had unbolted it from the bulkhead and moved it aside when I was refinishing the engine bay,  so I guess it might have been from original manufacture and have tumbled, and perhaps magnetically found this inconvenient new lodgings.   As a flake no thicker than a finest feeler-gauge - one had to see it from the right angle even to spot it.    

Hope that helps,  Pete.

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as far as adjusting these be they lucas or ford are a dark art, we had a enormous starter and alternator drive rig and spent a long time checking a engineers dynamo and box 

you could see the changes as adjustments were being increased but it ended in disaster it took all morning to destroy it,  later in life i helped tim hunt (CT) who wanted to change his charge rate on his TR4A  that took all day of adjusting checking and when all the facts matched the test data a ride down the road blew all headlamp bulbs   so lesson never learnt

dont mess with control boxes ...nightmare   

pete

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I suppose a quick look inside the Regulator to check the 3 contacts move can't do any harm (I'm not going to adjust anything though!) 

If I can't find any obvious faults I will have a check on my spare dynamo and see what condition that's in, then check the operation as my other one with a battery then when on the car and give that a try, its only a 20 minute job to swop one.

It's a bit annoying because the replacement Regulator is N.O.S. and was supplied in a sealed box, so hopefully no corrosion on any of the contacts, although being stored for 50 years or so can't help.

Old cars, don't you love emūüėź

  

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7 hours ago, Pete Lewis said:

one good reason to contemplate a A127  alternator much simpler

Hello Gary,

Agree with Pete and in fact I changed to a 127 type unit on my Alpine - it did in fairness have the original 11AC unit and not a dynamo.

It was a simple task of removing the separate loom and converting to the new unit; as it did away with all the potential electrical pitfalls.

Regards.

Richard.

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I suppose an Alternator is an option, although I was trying to keep the car standard.

A check of the Regulator to make sure none of the contacts are stuck closed or open will be the first thing.

An inspection of my secondhand Dynamo and see if it works will be the next thing

I'll also do a check & test on the wiring from the Dynamo to the Regulator too, although it is only a short run and I can't see this being the problem?

It seems strange that two Voltage regulators have given the same symptoms?  

Thanks for the advice, I will keep you all posted on what I find.

Regards

Gary

 

 

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1 hour ago, Gary Flinn said:

I suppose an Alternator is an option, although I was trying to keep the car standard.

My view on such upgrades, Gary, is that they either:

1- benefit the enjoyment of using the car;

2- the upgrade is done for safety;

3- that the upgrade can be reversed without detriment to the vehicles condition and / or integrity.

I agree that it will be prudent to ID the current (excuse the pun) cause of the smoke, which in itself is an issue that needs to be established forthwith.

Regards.

Richard.

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4 minutes ago, Pete Lewis said:

heavens above  why !!!

dynamator is a silly price  for a look alike and some members have had problems with them.

Pete

My dynamator lasted for 1500 miles ( a trip to Ireland ) replaced foc  . Dynamo put back though considering an alternator 

Paul 

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46 minutes ago, Pete Lewis said:

heavens above  why !!!

dynamator is a silly price  for a look alike and some members have had problems with them.

Pete

Had one, and sold it on very quickly. I read that very recently, that standard dynamos are becoming quite sought after and companies are struggling to meet demand. I think I've got a box of them somewhere, but all would probably require reconditioning.

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7 minutes ago, Colin Lindsay said:

but all would probably require reconditioning

Financially, it would still be worth doing if they are becoming that sought after - think I've still got mine [dynamo] when I switched to an alternator on the Vitesse.

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  • 2 weeks later...

An update on my Dodgy regulator, after removal of the cover I've found a link wire broken which is hopefully the cause of the problem?

I'm going to get the wire re-soldered (I don't possess a Soldering Iron but I know a man that does!)

Hopefully when this is done and I get it refitted the charging system will be back to normal.

It looks like the smoking was one of the resistors getting very hot (Photo shows this and also smoke damage to one corner of the Cover) the resistor doesn't seem to have burnt out completely?. 

I think the Dynamo output was going unregulated, the broken wire is connected to the Voltage regulator control coil and then linked also to the Current regulator coil, so no wonder I was getting a reading of 17 Volts and 25 Amps charge all the time!!  

The excess current may well have been travelling via the resistor to earth

A few Photo's and also a schematic I've found on line which shows how the regulator works 

Autolite Regulator Broken Wire.jpg

Autolite Regulator rear view.jpg

Autolite Regulator.jpg

VR Schematic.pdf

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On 16/10/2019 at 15:41, johny said:

Gary, did you find out why the NOS replacement VR was smoking as well?

Johny

I should imagine it was because the Voltage Regulator coil and current limiting coil couldn't operate correctly because of the broken earth wire shown in my photo.

It looks like one of the Resistors on the rear of the Unit was getting very hot, although it's still intact.

Previously we were getting readings of 17 Volts at the regulator 'B' terminal to earth and the Ammeter showed a charge of 25 Amps so not good!

I just hope it's not damaged anything else in the Electrical systemūü§®¬†¬†¬†

I've had my mate repair the link wire and tried it again.

Now the Ignition light stays on all the time so I think there is still something wrong with the N.O.S. Regulator!!ūüėĮūüėĘ

I've rang the supplier up and they have agreed to a refund, but I've decided to have a Modern Electronic version off them, this is about twice the price of the N.O.S. one, so they're going to knock the money I paid for the N.O.S. one off the new Electronic Version.

It's all very frustrating, I just hope the Electronic Regulator solves the problem?!!

A Photo of the rear of the N.O.S. Regulator showing the Resistor that was getting hot and also the Electronic one I've decided to try. 

If anyone with better knowledge of Car Electrics than myself thinks it may be something other than the Regulator please let me know?

When I tested the Dynamo after I cleaned up the Commutator and put the new brushes in it worked off the car as an electric motor would when I connected a Battery and once back on the car gave out just over 14 Volts at Tick-over speed (900 RPM) so I'm sure the Dynamo is working correctly?  

Gary

Autolite Regulator rear view.jpg

Electronic VR.jpg

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2 hours ago, Gary Flinn said:

Johny

I should imagine it was because the Volatge Regulator coil and current limiting coil couldn't operate correctly because of the broken earth wire shown in my photo.

It looks like one of the Resistors on the rear of the Unit was getting very hot, although it's still intact.

Previously we were getting readings of 17 Volts at the regulator 'B' terminal to earth and the Ammeter showed a charge of 25 Amps so not good!

I just hope it's not damaged anything else in the Electrical systemūü§®¬†¬†¬†

I've had my mate repair the link wire and tried it again.

Now the Ignition light stays on all the time so I think there is still something wrong with the N.O.S. Regulator!!ūüėĮūüėĘ

I've rang the supplier up and they have agreed to a refund, but I've decided to have a Modern Electronic version off them, this is about twice the price of the N.O.S. one, so they're going to knock the money I paid for the N.O.S. one off the new Electronic Version.

It's all very frustrating, I just hope the Electronic Regulator solves the problem?!!

A Photo of the rear of the N.O.S. Regulator showing the Resistor that was getting hot and also the Electronic one I've decided to try. 

If anyone with better knowledge of Car Electrics than myself thinks it may be something other than the Regulator please let me know?

When I tested the Dynamo after I cleaned up the Commutator and put the new brushes in it worked off the car as an electric motor would when I connected a Battery and once back on the car gave out just over 14 Volts at Tick-over speed (900 RPM) so I'm sure the Dynamo is working correctly?  

Gary

 

Sorry I thought it was the original that had the broken wire. So was it the same failure on the original that caused it to smoke as well? If it was thats very strange.....

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