What have I done?

Previously wrote:

I have just made a right balls-up, reverse- connected the pos/neg leads on my ES2 battery before running it up the road prior to its first MOT since massively expensive rebuild. It's a dynamo model and I don't seem to have any output now from the dynamo when I put a DC voltmeter across its terminals. (The ammeter also shows no positive charging) Could this have destroyed the dynamo? And before you say it, yes, I know. I am a twat.

Adam

Hi Adam, If you have a solid state electronc regulator you've probably sent it to th happy hunting grounds. If you still have the original regulator then I would have thought that it would have tolerated a reverse charge but I'm not sure, Rob.

Hi Adam, there is a good chance that the dynamo is ok. If you have the mechanical regulator I doubt that will be damaged. I'm not sure where you are measuring the voltage on the dynamo. All you have to do is remove wires from the regulator and short the the A (armature) and the F (field) output wires together and start the bike. Connecting theA to F outputs will make the dynamo produce it's maximum output and this can be measured between the casing (earth) and the two wires combined.

Removing the regulator from the circuit and testingwill verify if the dynamo is OK.

What may well have happened is that the dynamo might have been polarised in reverse due to the current surge backwards. To magnetise it back correctly you can simply flash the terminals back onto the negative battery terminal (IF positive earth) or reconnect to the the manual regulator. Remove the regulator cover and press down the cut-out plate for about 1-2 secs:

http://www.audioworld.net/BSA/manual54/controlboxmcr.pdf

It is the right hand coil as per picture.

This will connect up the battery directly to the dynamo and polarise the residual magnetism in the correct way. Also note the dynamo will act like an electric motor when powered this way.

If the dynamo is OK and it fails to work in circuitthen the regulator must be checked.

Further testing for the dynamo here:

http://www.audioworld.net/BSA/manual54/generator.pdf

Les

We are getting there. Reversing a dynamo polarity by 'flashing' it will not damage it at all, as we have seen here. A traditional electro/mechanical regulator will work on either polarity as well. Now reversing the battery on an electronic regulator 'might' kill it but the one I sell the V Reg 2a is designed with such misfortunes in mind ie it should survive provided you see the mistake early-high current through ammeter and flash on connections, maybe even a buzz from the dynamo as it tries to turn your bike into an 'electric backward' bike! and correct it.

When connecting F to D to check for output from the dynamo it is best to use a headlamp as a load, just using a voltmeter is insufficient, especially digital ones, they can give the appearance of a decent voltage when there is no real power available. Please use a 12V headlamp as a load. This means that a bright light at fast tick-over means you do really have 45 watts or so.

So to fully check a dynamo as above you can follow the same instructions on my web site aoservices.co.uk you need the V Reg2a fitting instructions.

Hope this helps.