stator rewire

[shocky]

i recone i have an intermitant fault with my stator want it rebuilt with new italian low tension coil and black box would like it converted to DC as well also longer wires ANY OFFERS to do it or any recomendations as to were for reasonable money or should i just get a bgm one

[tony]

Can you convert an a stator to dc? You can get a rectifier/regulator to do the job for you. I can rewire and fit the new bits tho mate, no prob.

[Knowledge]

It is unusual to find someone on a forum who puts themself forward as a wiring or stator expert, and believe me, I'm not going to change that, but I can perhaps offer some pointers.

I have fitted a PK XL AC/DC stator on my Lambretta so that I can run a battery. The four lighting coils are paired-up. The two that do the AC run from earth, through the two coils and then onto a yellow (?) wire into the regulator side of the 5 pin regulator/rectifier (R/R). The other two coils do not run to earth (at least, not on the stator) and have a wire either side of the paired coils. Both wires feed into the wiring loom (I think one goes to the R/R and the other to the battery).

What this does not allow for is the windings in each coil. They need to be the correct number of windings of the correct thickness of wire and wound the right way around (clockwise or anticlockwise). I suppose this is the secret to getting the best lighting: building coils that make the best use of the magnetism in the flywheel to provide stable and reliable volts to the R/R. If only I had paid attention during those physics lessons (was it the left-hand dynomo rule, or the right-hand motor rule.....?)

[lofty]

i think you will only ever get AC out of a lambretta/vespa style stator, as its the gubbins after it that does the rectifying/regulating..
most recent efforts have all the lighting coils just wired together to provide one output.. however there are a number of flavours that use different combinations of circuits tio feed different circuits, i beleive the first batch of AF electronics had a different configuration for the AC and DC versions..

i guess you would either need to look for a stator to 'copy' or alternatively look for a seconhand one that fills the need.

and i think its 'left hand rule' for motors.. i was taught 'motors drive on the left' to remember it..

[Knowledge]

Welcome to the forum Lofty (don't forget to introduce yourself on the "welcome" page).

Yes, I am also sure that you can't get DC direct from a stator, but I think that the way they are wired can assist the production of DC in combination with the correct regulator/rectifier.

My stator runs the lights, but it is not road legal yet so I haven't tested it to see how much power it produces, or whether it can keep the (small) battery charged.

[coaster]

Flemmings Right Hand Rule for generators (first finger = fielld, second finger = current, thumb = motion), I was taught GenerRIGHTers, daft but it stuck

[jonny snatchsniffer]

what you would need to make dc power would be a commutator which is would be time comsuming and not cost viable, even then you get pulsing dc, far simpler to use a vespa regulator/rectifyer

[J1MS]

Shocky... you have a PM....

[shocky]

cheers jimmers

[firekdp]

Yes, I am also sure that you can't get DC direct from a stator, but I think that the way they are wired can assist the production of DC in combination with the correct regulator/rectifier.

The way stators are wired depends on the load it has to supply and the required operating voltage. More turns = more volts, but more turns = thinner wire in the windings (occupying the same space). This factor is important because the internal resistance of the coils is what causes the voltage to fall as the current load increases and is why when stator output is measured without a load the voltage is far higher than expected. How many people have measured an unloaded 6v system and found the voltage to be far greater and decided the coils must be breaking down!
For example Innocenti lighting coils were designed to produce about 30W, supplying 5A at 6V. If the load was decreased by half to 2.5A the voltage would rise to 12V due to less voltage drop across the coils ( hence we get the easy 12V conversion). Now if we want to double the power to get about 60W we simply put another pair in parallel. Each pair capable of supplying 2.5A at 12V totalling 5A at 12V (the Lucas conversion).
The purpose made 12V Indian stator uses 4 coils in series, therefore each coil only has to provide a quarter of the total voltage output (ignoring the coil carrier size difference) so the coils need less turns, but the wire needs to be thicker to carry the whole current load.

When using a bridge rectifier to get full wave rectification, using a common earth on the ac and dc side would cause one half of the cycle to be shorted out. So it makes sense that it is the stator coils that are isolated rather than all the individual dc circuits and that is why coils destined for full rectification have 2 feeds out. If the coils have one end earthed then the best rectification possible is half wave.
All figures are approximate.

Does this make sense? Probably not