BSA Lightweight genny set electrical help

Folks,
I have just got a BSA genny set, there is a control box but nothing is connected.
There is a Lucas 49072 rectifier which is positive earth.
There is an ammeter which is not connected to anything and an on/off switch which has one terminal connected to the casing.  
There are 2 wires from the genny going to the 2 outer terminals on the rectifier. There is a 3rd wire coming from the genny (but I cannot see where) which is not connected to anything but is striped like an earth wire.
There are 2 cables which will connect to the battery that will I will be charging.
I would be grateful if someone can confirm what I am thinking or tell be where I am going wrong
The centre back cable from the rectifier is negative and will go to one terminal of the ammeter, the black cable that is going to the battery will go to the other terminal.
The red positive wire from the front of the rectifier will join to the red wire that will go to the battery.
I am now stuck, I cannot see what goes to the other terminal on the switch ?
Thank you in anticipation

Sorry I thought I had uploaded pictures

I have gone back to basics and taken the rectfier out so it is now producing AC, it was going to be too hard to drop the DC voltage

Mick sorry, you seemed to have failed to get any assistance with your issue but at least you have found a solution. I'm not familiar with your set, especially as I cannot see the complete unit from your pictures. What output did the set originally produce AC or DC, at what voltage? I imagine it may have been used for radio battery charging, in which case it would have been DC. Having got it operating and producing AC, I wonder what the output voltage is and how good the regulation will be. If you wanted it to produce a lower DC voltage, there are many DC/DC converters available for not much money.

Neil.

Hi Mick,

What AC voltage are you getting? Just remembered that I have a rectifier taken from a battery charger which might do the trick - you are welcome to it. Drop me a PM if interested.

If you are feeling flush, the real McCoy to be had here...
https://www.rexs-speedshop.com/product/genuine-lucas-single-phase-rectifier-lu49072/

Gents, Here is the engine. I did have a Lucas 49072 rectifier in it which was working fine and gave 110Vdc when measured across the red and black wires.
I was struugling to work out how to A) connect it to an ammeter and a switch and B) drop the voltage to 12Vdc without spending a couple of hundred quid, there are plenty of converters that convert AC to DC but not dropping DC voltage and you cannot input DC. I thought about using a resistor but the maths is beyond me.

What I ended up doing was disconnecting the rectifier, I have measures across the 2 leads fron the genny and I'm getting AC, the voltage is fluctuating between about 80 and 190.
I have ordered a converter from Amazon which has an output of 12V at 250W with an input of between 110 to 240 Volts. That will charge batteries and run a light box which I already have.

Paul thank you for your kind offer but I have one  

What a neat unit! Hope your converter does the trick.

Alan

I agree with Alan, a tidy looking unit. I do have a small BSA charging set in my shed which I will try to look out to see what the electrical arrangements are. If I remember correctly it is fitted with sprung crocodile clamps for attaching directly onto battery terminals. I cannot remember if it is 12 volt or 24 volt, it might even be switchable. If I can, I will see if I can get the unit out tomorrow and post a picture of it.

Neil.

Hi Mick, in between the cloud bursts and the high winds, I managed to recover the BSA generator set out of the shed. I don't know if the engine on this set is the same as on yours but from what I can see of it, it does look similar. I believe my one is a 50cc engine. The generator is certainly different with my one rated at 6V/30A, 12V/25A and 24V/12.5A, although I have not yet discovered how the voltage selection is made. However, although there is a rope start facility, I have found out that the set is designed to be started by motoring the generator, using the battery. I thought I would try this, as it would prove if the generator windings and brushes were in good order. I took the chance that the unit was set for 12V operation and connected a battery, which happily spun the engine over, with the plug out. Unfortunately it didn't produce a spark, so I imagine I will need to clean the points, at the very least. I don't have any technical information on the generator or the engine itself, so I will be looking for some help when the time comes but that will be after I have finished the Scott generating set.

Sorry, I hope I haven't highjacked your thread!

Neil










The BSA generating set as pulled out of the shed, where it has sat untouched since I acquired it, about 10 years ago! The exhaust has been "borrowed" for another project.




Engine number stamped on the casting. Can the set be dated from this, I assume it to be somewhere in the 60's.




Generator spec. plate identifying the manufacturer as W.E. Conyers Ltd and indicating the various outputs available.




Generator end cover with the output terminals, ammeter and the push to start button located at the 1 o'clock position.

Neil,
As far as I can find out, it could be my poor Googling skills, there is no way to date these smaller engines. Mine is 65  AA 6254. I am guessing the first 2 numbers are the CC, yours will be 50cc mine 65cc but after that nothing. Someone posted last year without sucess. Was your type designed for farmers to charge batteries in barns etc.?

Mick, yes I believe the general idea was for these units to be used by farmers / mechanics, for battery charging in the field.

Although I said I wouldn't be looking any further at this set until I had finished the Scott, I weakened. Due to poor weather conditions for painting, I decided to have a quick look to see if I could restore the spark. The complete cowling, recoil starter and petrol tank was simply removed, to reveal the flywheel. The flywheel is keyed onto the output shaft, requiring a puller to release it. Not having anything suitable, I used a large washer which I drilled three holes in, to align with the threaded holes in the flywheel. Unfortunately the centre hole in the washer was too big, so I used a smaller one, in between the extractor and the shaft. Once screwed down, a gentle tap on the end, easily released the flywheel. The condition inside the flywheel looked to be very good with no corrosion or any signs of wear. A rub of emery paper on the points and I was ready to put it back together again. A quick spin of the engine, using the battery starter, produced a healthy spark. Having got this far I had to see if there was any life in the engine, a little fuel down the spark plug hole, got the engine running for a few cycles, enough to convince me that there wasn't much wrong with it. I have since filled the carb with a little fuel, which resulted in a more continuous run of 15 - 20 seconds. Further investigation is needed, to fully understand the governor set up, as I think I may be missing a control spring. I will also be cleaning the tiny Zenith carburettor, to ensure all the jets are clear.

I feel I should thank you for your initial post, without which I would not have been encouraged to get my generator set out of storage after all this time, to see if it would run. I suppose I should really start a separate thread, if I'm going to continue with this restoration.

Neil.



Home made extractor in position ready to remove flywheel.




Condition of the inside, once the flywheel had been removed. This is as revealed, nothing required cleaning, apart from the points contacts!

Just a quick update. I put a 13amp socket on the green box and got a 110/240vac to 12vdc converter from Amazon for £13.45. I put the converter in a box with a spare computer fan for additional cooling and it works a treat. Thanks to all for your help