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Mechanical Regulator Question.

Posted: Mon Apr 15, 2019 10:25 am
by robert.clark
So I just rewired my 500cc RH500. New harness, reconditioned dynamo, new mechanical regulator (sure its a Wassel). Soldered joints throughout.

Not running with battery connected everything works perfectly with ammeter showing a discharge with lights on. When the bike is running I have a steady 4 amp charge at the ammeter with lights on. When engine is stopped and lights off I see a very slight discharge on the ammeter, to clarify that is a very small fraction of the discharge shown with the lights on and not running.

When I connect the battery I can hear the regulator activate. I believe this is the reason for the discharge.

Before I do anything else with the regulator ( adjustments etc) has anyone any experience of what may be happening here.

I should mention I have now introduced a on / off switch at the battery to prevent the battery totally discharging with the battery connected.

Many thanks Rob

Re: Mechanical Regulator Question.

Posted: Mon Apr 15, 2019 7:49 pm
by alan.moore
If the regulator is working correctly there should be no need for a separate on / off switch as a cut out switch / solenoid is incorporated within the regulator. It sounds as though the cut out section of your regulator is not operating correctly. The cutout points (which isolate the battery from the charging system when the dynamo is not charging) should only close when the dynamo reaches a certain voltage. This function can be adjusted by following the instructions in the Lucas documentation, which is on the AOMCC website 'document repository' under GENERIC / Lucas Electrics.

I know the following does not solve your issue but I have read on other forums that folks do have problems with the 'new' mechanical voltage regulators which are produced in India, maybe this is the type you have? You can fiddle around all day trying to get them to work correctly but the only way (in my view) to get as reliable system is to fit an electronic solid state regulator.

Yes the Lucas mechanicals do work, and have done so for donkeys years (the one on my Triumph is still going strong after 60 odd years and I have an MCR2 for the WNG which, having been adjusted works fine. But having played about with the MCR1 on the VH for days and days it was clear that it was never going to work correctly.

I bought a DVR2 solid state and it worked perfectly, started charging at low revs (which some other makes of electronic ones do not do) and was a breeze to wire in (the Wassel ones in particular appear to be problematic as you have to change the way the dynamo is wired if you have negative earth). The cost of a electronic is not much more than a 'new' mechanical.

So.....I think you need to go back to basics and check the regulator is working within its design perimeters by following the Lucas test procedures outlined in their documentation. Hopefuly you can get that regulator back on track.

Cheers
Alan

Re: Mechanical Regulator Question.

Posted: Mon Apr 15, 2019 8:44 pm
by will_curry
Four amps charge with the lights on sounds to be too much.
It should just about balance.

What's surprising is that the discharge is so small. When you manually actuate the cutout
with the dynamo stationary the ammeter usually goes to full discharge and things can
get quite hot.

The cutout should be actuated by the voltage being generated by the dynamo rising to
a level higher than the battery voltage, charging the battery and running the lights.
When the dynamo voltage drops below the battery voltage the cutout opens and disconnects them
so the battery doesn't flatten.

It sounds like there is a short somewhere in the unit - try taking the cover off if it's one
of the sort held on with a wire loop. I've seen several Indian ones where the cover
shorted against the body of the unit and caused problems.

Re: Mechanical Regulator Question.

Posted: Tue Apr 16, 2019 4:21 pm
by robert.clark
Alan and Will thanks for responding. I have spent some time fiddling without success and quite frankly this option is against all my normal views on technology upgrades. I've looked at the DVR2 unit, it sounds fine and I've ordered one today.

Re: Mechanical Regulator Question.

Posted: Tue Apr 23, 2019 10:37 am
by robert.clark
All fitted the new unit works a treat.