PMA is the SOURCE of PROBLEM - HELP!

ANLAF

ANLAF

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Fellers

I found the source of my burnt-out battery and regulator-rectifier - it turns out that the source of the problem was the PMA. Symptoms - 15.4-16+v measured with wired-in voltmeter and multimeter. Diagnosis - regulator part of the regulator-rectifier not working.

I exchanged emails with Hugh and sent him pics (I have a Hugh's Handbuilt PMA and reg-rec combo). Hugh said he would send me a replacement reg-rec, but I wondered why the regulator failed if there was anything else I could do to check the PMA because the ohms readings at the plug tested with the multimeter only gave one reading of three (should have three consistent readings). Hugh suggested I pull the PMA and check the soldered connections from the three wires to the copper of the coils. Yes - there was the source of the problem, one connection completely separated. Some soldering was done, PMA refitted but it fired-up only on the battery - there was no charge going to the battery at all from the charging system (multimeter across battery terminals).

I got back to Hugh but I haven't got a response in over a week. Does anyone know if he is away.

HELP! - Has anyone any idea if I can do to anything to fix the bike? I'm desperate to get Back on the road.

ANLAF
 
Do the multimeter test again, across all combinations of the PMA's three wires, including ground. Don't want any opens on those three, or shorting to ground...
 
TwoMany

I'll do the test s again. By 'opens' I take it to mean open circuits (need to test all wires for continuity then) and for shorts that I may not have spotted. I'll go through it with a fine tooth comb.

Thanks

ANLAF
 
TwoMany - just did the test.

I followed the first part of the three tests in the YouTube video at...


...that's multimeter set to ohms between each of the phases. I'm getting 0.7. But then I check each phase to ground - the reading on ohms should not register, but I'm getting 0.7n on each.

Looks like that good-old grounding issue has raised it's head again. Either the PMA is toast or there could be something obvious between the PMA and the connection with the reg-rec.

I'm going to pull the PMA again and follow it through. My feeling is that three phases all grounding might mean I can smell the toast. Fingers crossed for some obvious short fault I can fix.

ANLAF
 
Correct me if I'm wrong, but you cannot protect your PAMCO, etc from this via fuses, because fuses don't care about voltage. Is there anything that CAN be done to safeguard against this for those running a PMA?
 
Oakbehringer, I don't know. I'm running Boyer, but same concern, though. I am far from an expert in electronics, but the current (amps) cannot get be greater than the 10amp fuse.

ANLAF
 
OakBehringer said:
Correct me if I'm wrong, but you cannot protect your PAMCO, etc from this via fuses, because fuses don't care about voltage. Is there anything that CAN be done to safeguard against this for those running a PMA?
Click to expand...

That's true. Fuses protect against high current not high voltage. I believe Pamcopete already has some voltage protection in his circuits. However, its likely limited to how much it can handle. If he was to design his circuits to handle everything possible, he would have to charge a lot more money.

The PMA regulator is supposed to do its job, so high voltage does not happen. I don't know where Mikesxs and Hugh buy their regulators from, but I suspect they come from Taiwan/China. The regulator is mass produced in large quantities, and perhaps the components are low quality/poor design.

There are things such as Zener Diodes, I.C.s, and Triacs that can be built into a protective circuit. However, now you will be paying almost as much money as a replacement Pamco circuit board.

I use a stock OEM alternator and a very reliable/rugged automotive regulator. I have no concerns at all about over voltage.
 
TwoMany,

I found a short of my own creation when I re-fitted the PMA last week. No grounding, but still no charge to the battery.

I have my fine-tooth comb out to go over ever wire and connection looking for any elusive open circuits and shorts.

ANLAF
 
retiredgentleman said:
That's true. Fuses protect against high current not high voltage. I believe Pamcopete already has some voltage protection in his circuits. However, its likely limited to how much it can handle. If he was to design his circuits to handle everything possible, he would have to charge a lot more money.

The PMA regulator is supposed to do its job, so high voltage does not happen. I don't know where Mikesxs and Hugh buy their regulators from, but I suspect they come from Taiwan/China. The regulator is mass produced in large quantities, and perhaps the components are low quality/poor design.

There are things such as Zener Diodes, I.C.s, and Triacs that can be built into a protective circuit. However, now you will be paying almost as much money as a replacement Pamco circuit board.

I use a stock OEM alternator and a very reliable/rugged automotive regulator. I have no concerns at all about over voltage.
Click to expand...

That's what I thought. Bummer.
 
Retiredgentleman

What is that reliable and rugged automotive regulator. Can one of those be wired in even if the a reg-rec in there? or is it a separate regulator and rectifier set-up?

My second bike has the OEM rotor/stator, so that is interesting.

ANLAF
 
ANLAF said:
... multimeter set to ohms between each of the phases. I'm getting 0.7. But then I check each phase to ground - the reading on ohms should not register, but I'm getting 0.7n on each.

Looks like that good-old grounding issue has raised it's head again. Either the PMA is toast or there could be something obvious between the PMA and the connection with the reg-rec.

I'm going to pull the PMA again and follow it through. My feeling is that three phases all grounding might mean I can smell the toast. Fingers crossed for some obvious short fault I can fix.
Click to expand...

ANLAF, 3-phase windings can get complicated. For a 3-wire stator, there's two styles, Delta (shaped like a diamond), and WYE (shaped like the letter Y, also called 'star').

Our bikes use the WYE configuration, as in pic #1. The center common tie point is floating, and not connected to ground. Your test shows that this center tie point is grounded.

Where it gets messy is the actual winding layout, either series or parallel coil layout, as in the two left figures in pic #2. There could be multiple interconnects, with failed solder joints touching the stator frame. And they could be buried where you can't get to them...
 

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ANLAF said:
Retiredgentleman

What is that reliable and rugged automotive regulator. Can one of those be wired in even if the a reg-rec in there? or is it a separate regulator and rectifier set-up?

My second bike has the OEM rotor/stator, so that is interesting.

ANLAF
Click to expand...

For a 1970 to 1979 OEM alternator with brushes, you can use an automotive VR-115 regulator. If the bike has a combo rec/reg, you would remove it and install a separate rectifier and a separate regulator, such as the VR-115.
 
Retiredgentleman

Thanks for that info. I just checked-our the VR-115, and they look easy enough to wire in to the stator. Next thing I suppose it to know which comes first in the wiring circuit, the regulator or the rectifier? And then after that, what rectifier do you use. I recall you put one together yourself (series?) or is my memory fading?

ANLAF
 
ANLAF said:
Retiredgentleman

Thanks for that info. I just checked-our the VR-115, and they look easy enough to wire in to the stator. Next thing I suppose it to know which comes first in the wiring circuit, the regulator or the rectifier? And then after that, what rectifier do you use. I recall you put one together yourself (series?) or is my memory fading?

ANLAF
Click to expand...

This link should have all the information you need:
http://www.xs650.com/forum/showthread.php?t=21485
 
The stock OEM alternators generate a maximum of 16 amps. I use rectifiers rated at 25 amps. That provides a safety margin.

To use anything larger that 25 amps, means they will likely be physically larger, use a larger heat sink, and cost more money.

There are no advantages to using larger than required, but there are the mentioned disadvantages.
 
The PMA problem?

I measured the AC voltage reading at the PMA three yellow wires connecting to the reg-rec. AC voltage reading between 16 and 21. Sounds to me as if the PMA is behaving itself now its soldered.

Hugh has said for me to send the set-up back to him for testing - which is great support, but I'll do what I can here first to save him the cost of the postage from this end by trying to find the source of the problem. If AC reading of 16-21v is in range, then it might be back to being a simple and easy to remedy reg-rec failure.

Anyone know the AC voltage reading a three phase PMA should show?

ANLAF
 
I can't say on the PMA but the stock system, I was doing some testing and found that with the reg/rec unplugged, jumpered the brushes to bypass the reg/rec I got about 20 volts AC on all the white wires.
I assume a PMA would be in the same area.
Leo
 

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