Voltage Regulator troubleshooting

[xib34]

My generator put out good volts but the old Lucas regulator put out zero.  So I bought a brand new regulator made in India and same thing.  Is it a coincidence that this brand new regulator would be bad?

Details:  After running my 1962 Spitfire Scrambler without a generator or lights for some years, I reinstalled the old 6 volt generator and Lucas mechanical regulator (no battery).  Lights don't work.  Tested output direct from generator like the shop manual says, and get 7.5 volts at fast tick-over, like it says I should.  So I tested output from the regulator and got zero volts.  So I bought a brand new regulator made in India and exact same thing!  I tested the lighting system seperatly with a battery and it works fine.

[trevinoz]

I have found that the Indian regulators need to be adjusted as per specifications, points cleaned and then set.
Quite often they have dirty regulator points, which may be what is wrong with your original regulator.
If you can use a multi meter, set it to the lowest ohms scale.
Test between "D" & "F". The resistance should be close to 0, probably 0.3 or so on a digital meter.
Press down the regulator armature and the resistance should be anywhere between 35 - 50 ohms.  If the initial resistance is high, clean the points.
Normally the cut out points are OK.
Test with the ohm meter between "D" & "A". The meter should show an open circuit. Press down the cut out armature and the reading should be as close to 0 as the meter can read.
Good luck!

Trev.

[wilko]

Dont spose you'd know what the short regulator reading is on the armature regulatore with no resistor? I have a few of these I haven't tested yet for the 45 watt version.

[bikerjohndavies]

Have you tried running with the regulator cover off. I have had a number of these Indian ones and they all seem to have a too large blob of solder on one of the connections that touches the cover and therefore shorts out to earth. I put tape on the inside of the cover to insulate and all fine. Also may be worth checking the polarity of the dynamo. Cheers, John

[BSA_54A10]

And as per my name sake 200 km north,
If I don't ride my m20 for more than 4 or 5 months the points oxadize and there is no out put.
One wipe with a 4" length of 600 paper lubricated with WD 40 and the candle lights

[xib34]

Thanks guys this gives me some things to go check.  Although I did not want to take the regulator(s) cover off, guess I will have to.  I did polarize the dynamo (positive earth) and then on checking output with voltmeter I put the positive cable on the voltmeter to earth and got 7.5 volt reading so the polarity must be correct.   

[xib34]

Trev I took the case off the old regulator (an RB108, DEAF) and the measured resistance between D and F is 0 ohms, then when I press down on the regulator armature it is 43 ohms.  Resistance between D and A is "open", and when I press down on the cutout armature it is 1 ohm.  So that seems all ok.  But I then cleaned both points with 400 grit paper anyway, and there was no change in readings.   Maybe I should re-install this unit and see what happens?  Not sure tho since I didn't change anything much.

[trevinoz]

xib,
           You need to have a look at the regulator with the engine running and see what is happening. It is much easier on the bench with a spare dynamo.
Before you start, make sure that all of your connections are good and that you have continuity. Make sure that the "E" terminal has a good earth to the frame and the dynamo body must also have a good earth.
Run the engine and measure the voltage at "D". If OK, measure at "A". It should be the same. If not, check if the cut out is closing.
As you have clean regulator contacts, you should have voltage at "D". If not, try wedging the regulator armature open. You should then get an unregulated voltage at "D".
Measure the resistance between "D" & "E" before you start. Should be around 25 - 30 ohms, from memory. If it is higher, around 45 ohms, I would suspect an open circuited shunt winding on one of the bobbins.

Wilko,
            The MCR1 regulators have similar measurements to the others.
They do have a resistor, it is a resistance wire wound around the regulator bobbin, making 3 windings in all against the others 2.

Trev.

[BSA_54A10]

FWIW  I had Peter Scott do my mag back in the 90's.
It worked beautifully on the bike, for about a month so I took it back, it checked out OK so he asked for the regulator.
Set up on his lathe the difference between not charging and melting the solder on the amature was 3/4 turn.
I had it set at least 1 full turn out.
That was the last time I even thought about trying to adjust a regulator on bike

[Butch (cb)]

I found two amongst the detritus when I was putting my bike together. Didn't even think of fooling with them - just went solid state. And I'm one of the 6V Luddites on this forum.

[xib34]

You won't believe this.  I did all the tests, everything fine, still no output past the new regulator.  Someone had mentioned a blob of solder on one of these cheap Indian regulators shorting against the cover.  I noticed one of the gizmos soldered to the base, a resistor I think, had one end sticking out past the base so it may hit the cover.  I used my voltmeter with the cover on and off and it said yeah this thing is shorting out.  So I left the cover off and reinstalled it on the bike.  Fired the Spitfire up, still no lights.  Turned the switches on and off, reved the engine some.  Lights!  They were reluctant and flicker at low rpm because I don't run a battery.  I bet the old Lucas regulator has something simple wrong with it too.  It just takes so long to find something simple like that, when you isolate something to one bad component, and replace it with a new one, and it still acts bad.  So now I'm riding around with an exposed regulator.  I will tell anyone who notices it is to save weight.  It is very crude inside compared to the Lucas.

[duTch]

 I had a similar issue, as did someone else a while back but wasn't just a blob of solder but the actual bobbin carrier was touching in a couple of places.
 I carved some off  the corners,and insulated the inside like what Bikerjohn did. Turns out the cover is about 5mm shorter than the original brass one, and even that was touching.

 Regarding adjustment, armed with the Lucas 'how-to', and an extension loom I made up, I gained some good satisfaction from playing with it. Isn't really all that hard and kept me entertained for a while.

[trevinoz]

It is not uncommon for the shunt windings to open circuit.
Open circuit cut out winding = no output.
Open circuit regulator winding = uncontrolled high output.

Trev.

[xib34]

I will modify or put some tape inside the cover so it does not short out on that component touching it.  Thanks for the help!