LUCAS RM13 or 15 alternator wire colours

[rhyatt]

in my stock to be used on another project, I have the above alternator - it has open windings not encapsulated.

the trouble is the wire colours are so old and discoloured and brittle that i would like to renew them by soldering on new lengths.

But - I just cannot ascertain which tag has which colour - which doesn't help things !!

I have 2 wires adjacent to each other on 2 adjacent coils and they're on the same side of the stator and the 3rd goes through between 2 coils to the other side.

If anyone has a similar stator , could you please have a look at their colours and describe to me which goes where?

would be grateful - electrically, it is sound , nothing going to earth and around 1 ohm (give or take) across any combination of the 3 tags.

[JABBA99]

Alternator typical wiring as attached (from Lucas service manual) ...  WG (White / green) is common .... GB (green / black) is charging output (two coils in series to common)  .... GY (green / yellow) is "headlight" output (two parallel sets of two series coils to common). 

Not sure if you can see enough of the wiring to work out which coils are connected to which points.  I believe the series pairs should be on opposite sides of the stator for most even output.

As you have a reistance meter you should be able to check .... GB to WG should be about 1 ohm (from memory) ... GY to WG should be about half previous measurement ... GB to GY should be about 1.5 times original measurement.  Hopefully with the set of measurements you can work out which is which?

[rhyatt]

great , that's helpful

sadly , my wires are so discoloured and brittle I cannot tell which colour is on which tag -
i have found 1 ohm across 1 pair of tags , so i will have to take them as the charging coils ( WG and GB)
and I have found 1.5 ohms across another pair of tags so will have to assume those 2 tags are WG(common and GY (main output coils)

I will join the GY and GB together and hopefully get 12v output

thank you

[JABBA99]

The 1.5 ohm should be GB to GW.  Check each of these to the third (WG?) .... do you get around 1 ohm and 0.5 ohm?

[rhyatt]

GB to GW gives me 1.0 (from original  GB to WG should be about 1 ohm (from memory)

GY to GW gives me 0.5 ohm (original GY to WG should be about half previous)

G/Y to G/B gives me about 1.4 ohm (from your original answer GB to GY should be about 1.5 times original measurement. )

now correct readings

in your 2nd message, have colours changed please? or is it my eyes !!

[JABBA99]

Looks good except your GW should be WG (White with thin green stripe)

[rhyatt]

Great cheers