dynamo headache

[matthewcoxall12]

i will tell the story as i know it and be aware i have about 1% electrical knowledge just what i have picked up along the way
this is a picture of the wiring set-up i have on my Lister d now this set-up has been tested and i ran a 240 v drill and then a 240 sander with the voltage meter decreasing at a very very very slow pace nothing to be worried about for a day rally so i thought great lots of power i was not going to complain about where it was coming from (as its a 12v dynamo attached to a 12v battery running a 240 drill at full speed) anyway i picked up one of those old spinning police lights the other day at the boot sale and i thought i would give it a test on the dynamo so i wired it up as all i got was a tiny little glow from the bulb and the thing was not spinning. thinking the light was broke i got out the 12v power pack and tested it and away it went perfectly so attached it back up to the dynamo and the same only a tiny glow from bulb and no spinning so my question is how can my dynamo produce enough power to run my drill and sander but not enough power to run a 12v light

 

[Lighthouse Phil]

Maybe the reason the blue light was in the boot sale is because it don't work.......
Still,,,cant see how your running 230V equipment on a 12V dynamo / battery...

 

[matthewcoxall12]

the blue light works fine on my power pack and the dynamo is hooked upto a lister d 2hp stationary engine running at about 500-700rpm

 

[Lighthouse Phil]

I'm still lost with the idea that your running a drill / sander, both 220Vac appliances, from a 12Vdc battery...

 

[Adam W]

I don't get any of that.
Are you using an ac motor as a dynamo and running that off the engine, hence producing ac voltage, and the battery is just 'there'?
How are the battery, dynamo and socket connected together? On your drawing you've just drawn 3 terminals.
Is this spinning light actually 12v, or is it a 230v disco effect?

 

[matthewcoxall12]

a few picture of the set-up and the picture of the wiring at the back of the dynamo i have not changed this it is the same as when i purchased the engine the guy did say he did some work on the dynamo and he rewound it if i disconnect the battery either red or black terminal then the power will stop to the plug

also the blue light is an old police light the ones that use to go on the roof and yes it is 12v

 

[Adam W]

How is the dynamo wound?
What happens when you just connect the light to the battery?
Then what happens when you just connect the battery to the drill?
With the battery disconnected what happens if you short out the connectors which would have gone with it and run the motor with the drill plugged into the socket?

Lastly why are you using a dc battery with an ac socket?

 

[matthewcoxall12]

i do not know how the dynamo is wound it was wound previous to me owning it he said it can from a car and something about converting it to generate but i don't understand any of that

when i connect the light to the battery it turns fine with the light fully lit

the drill will not even jolt or do anything when i connect it to the battery

if i disconnect the battery so it is free and away from the dynamo and short the black and reg i get a shark
and if i try and run the drill in the socket with the battery disconnected from the dynamo it doesn't work it seams the battery is completing the circuit

sorry for my lack of knowledge as you can tell im a engine enthusiast not an electrician so bare with me and i will try answer the questions as well as i can

 

[Lighthouse Phil]

Love the look of your Lister,, I work almost daily with Lister HR's, TS's ST's and Alpha's..2 and 3 cylinders..
The drill will not work with the battery as the battery is 12Vdc, the drill requires 220Vac, ie, mains voltage.
I'm still at a loss as to how you got the drill / sander working on the battery, as you said earlier...

 

[matthewcoxall12]

come have a look anytime you want mate

the drill and sander only work when they are connected to the plug with the engine running and the circuit is completed with the battery they are not attached directly to the battery

 

[Adam W]

That is what I thought - I reckon the 'dynamo' is actually generating near enough 230vac and the battery is just completing the circuit. If you take the battery out and join the 2 connectors together (obviously do this while the engine isn't spinning) I suspect the drill will work via the socket.

I reckon the battery would need to be connected in parallel across the 'dynamo' via a charger, and probably some kind of fuse.
To get the 230v socket to work off the battery you would need an inverter, or you could just use the battery for the flashing light.

 

[matthewcoxall12]

i did try this if i even thought the engine was spinning if i connected the black and red from the battery nothing happened the drill just stopped i dont think it is set up right because they must need some volt to charge up the battery (ahhrrr my head is crammed with to many thoughts now) it doesn't make sense

(That is what I thought - I reckon the 'dynamo' is actually generating near enough 230vac and the battery is just completing the circuit) this i agree with but the other part well i have explained but i dont understand why i need a battery there to complete the circuit and they dont complete without the battery hooked up ???????????????

 

[Geordie Spark]

I'm clutching at straws here because I know very little about generators & suchlike, but is the battery there to excite the coils in the dynamo?

 

[matthewcoxall12]

arr now there is an idea maybe so

 

[Knobhead]

Are the drill and sander old with no variable speed? If they are they will run off DC. If you have a voltmeter check the output to the socket it will be 100V+ due to the dynamo running without a regulator.

Ingenious little set up

Good job you didn't try the light on the output it would have gone in to orbit.