MHR alternator

[big phil]

hi all. i have just rebuild a 83 MHR for a friend. The alternator has 3 wires, 2 yellow and 1 red. All the other square case bevels i have seen have a 2 wire alternator, 2 yellow, and the regulator has the reciprocating 3 pins as well as the 3 pins for the batt, light and the other one. All the wiring diagrammes show 2 wire alt. does anyone know where and why this has 3 wires and if i can connect a regulator with 2 pins and bridge the red wire to the battery?

[big phil]

seriously, anyone????

[BevHevSteve]

Suggest you download both wire install diagrams for the regulators I stock showing both 2 wire and 3 wire installations.

[big phil]

cant download them without the purchase mate

[BevHevSteve]

Yes you can it happens all the time, login to your account and complete checkout.

[Bern]

hi all. i have just rebuild a 83 MHR for a friend. The alternator has 3 wires, 2 yellow and 1 red. All the other square case bevels i have seen have a 2 wire alternator, 2 yellow, and the regulator has the reciprocating 3 pins as well as the 3 pins for the batt, light and the other one. All the wiring diagrammes show 2 wire alt. does anyone know where and why this has 3 wires and if i can connect a regulator with 2 pins and bridge the red wire to the battery?

Definitely not, the battery should only ever be connected to rectified and regulated power. Any wire coming straight from the coil doesn't meet this criteria.

What you need to do is determine how the coil is configured, do this using an ohm meter. Disconnect the coil from all circuits, measure the resistance between the two yellows, then measure the resistance between each yellow and the red. If the resistance between the yellows is double that of the yellow-reds then you have a centre tap coil. If they are all equal then you have a three phase coil which is very unlikely. If the yellow red is open then you have a single phase coil and you can ignore the red wire.

Once you know the type of coil you have you can determine what sort of regulator you will need or how to connect it to your current regulator. I'm pretty sure you can test what type of regulator you have using an volt meter and a 12 volt battery, I would need to think about this a bit to figure out a meaningful test.

Why don't you post a pic of the regulator and any numbers/markings it may have on it.

[big phil]

well, after a bit of research and experimentation, i have found some earlier roundcase bevel diagrames with the 3 wire alternator , and they either connect the red with one of the yellows, or the red to the battery cable which also plugs into the reg. i have tried both, and now get minimal charge out of the reg to the battery when i connect the batt to the red wire of the alt. the other way doesn't work. i have the feeling that i have a problem with the alt as well. either way, i have to get a new reg.

[Bern]

well, after a bit of research and experimentation, i have found some earlier roundcase bevel diagrames with the 3 wire alternator , and they either connect the red with one of the yellows, or the red to the battery cable which also plugs into the reg. i have tried both, and now get minimal charge out of the reg to the battery when i connect the batt to the red wire of the alt. the other way doesn't work. i have the feeling that i have a problem with the alt as well. either way, i have to get a new reg.

Take a peak at my previous post on 750 GT alternator conversion. It will give you an idea of what is going on and how you can possibly upgrade your current alternator. I would try replacing the old rotor with one with stronger magnets first and see if this solves your problem.

[enforcer]

what Ohm reading should you get on the centre tap windings ?