Dynamo / Electronic regulator woes

[Keith.owen]

Hi,
I am about to have a terrible crisis of confidence. I cannot for the life of me get my charging system to work.

I have tried two dynamos- neither works with the regulator. I sent the regulator back and the manufacturer tested it and said it was ok. So, I completely rebuilt one of the dynamos with a new field coil and armature (my previous thread about the commutator). In truth it tested just the same as before.

I have an electronic tacho on my bike (one of those Chinese devices that has a wire that wraps around the spark plug lead).

If I disconnect the dynamo and link the filed and dynamo leads together and run up the engine, with a voltmeter connected between these and ground,, the dynamo is outputting between 7-8 volts at around 750-900 RPM. The field coil itself is drawing about 2 amperes (coil is about 280 ohm). If I connect a 12 Volt 21Watt bulb across the voltmeter and rev the engine I can easily get 12 Volt (bulb lights brightly) at around 1500 RPM.

I think the dynamo is OK so why won't it charge?

I have checked all the wiring. With the VR disconnected, if I connect my battery to the lead going to A and switch on the lights all works fine (except I don't sound the horn because I don't want to harm the ammeter) - no ammeter reading. If I connect the battery normally then switching on the lights gives me a discharge reading at the ammeter.

I have buzzed out both wires F and D to the dynamo - again fine. I have checked the earth continuity and it measure 0.1 ohms. I reversed the polarity of the meter and got the same reading.

The only thing I can possibly imagine is that the dynamo doesn't output enough voltage without the field coil in circuit to switch on the regulator?

My battery is fine (6.1 V).

Has anyone had similar issues?

Keith

[simon.holyfield]

What does the battery voltage read when you rev the engine?

[Keith.owen]

Hi,
No change. I have even isolated the output of the regulator and noted that the regulator is not supplying voltage.

Keith

[simon.holyfield]

What about the voltage at the A terminal, with the bike running? I had to repair an ammeter for someone recently.

Incidentally, did you see Mark Walsh's post on the same problem?

[Keith.owen]

Hi,
I checked that. First I removed the fuse between the regulator and the Ammeter / light switch. I ran the engine up and looked for voltage on the A terminal at the regulator and there was none.

I seems as though the regulator is duff, but it is brand new (yes I bought another one, a Wassel, this time).

You have to modify the wiring of the Dynamo field coil, which I did and I ran up the engine with the regulator disconnected to verify that the polarity of the dynamo output is correct, which it is.

Keith

[paul.jameson]

I had some little difficulty getting the Square to charge when I first rebuilt her but eventually found that applying 400 grit wet and dry paper to the commutator solved the problem. It was a new armature / electronic regulator / wiring / etc. but clearly, I wasn't getting enough output to get the whole thing going. Since the initial problems, no trouble whatsoever.

[Keith.owen]

Hi Paul,
I'll give it a try.

Keith

[bill.bottrill]

Hi Keith
I will tell you what I would do in a situation like your's, I would turn off the ignition, disconnect the battery terminal, quitely close the garage door, make yourself a nice cuppa tea. Then I would get hold of an old style mech. regulator put everything back to standard on the bike, including the reworked field coil (slightly worrying that!) connect in the mech. regulator, these have been used for decades and the circuitry is known and works so if it doesn't work throw it and borrow one that does.they are so cheap to get hold of, you can then fault find from a known position (no black box with a mystery inside it) you can see all the circuitry and can poke around with a voltmeter easily. Once it's O.K. you can reinstall the electronic box again ,Alot of folk just have to replace the mech regulator with electonic ,there's really no need the old system is perfectly o.k. cheers bill

[Keith.owen]

Hi Bill,
You know what? I kept the internals of the mechanical VR and was just yesterday thinking of doing what you suggest.

I'd almost put money on that it will work!!

Thanks for your 'sensible' suggestion!

BR,
Keith

[MARK.WALSH]

Keith
be interesting if the mechanical regulator works as I have had similar problems with an AO reg. I went back to a mechanical one and it works fine - I cant figure it out unless I bought a duff one.
Good luck