Author Topic: Motorcycle Shunt Regulator ?  (Read 1670 times)

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Offline Pete

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Motorcycle Shunt Regulator ?
« on: July 13, 2017, 05:54:13 pm »
My motorcycle regulator recently died. As the whole thing is encapsulated in black epoxy repairing it is not going to be easy.
Does anyone have a way of getting the circuit board out of the epoxy?
Second thing is that the alternator on the bike is a permanent magnet type, as such the regulator is basically a heat dump. They are known to fail on my bike model (BMWF650). The alternator is a 300 watt job, the regulator is under the seat (not such a great place to dump 300 watts or so).
There are suggestions on moving the regulator to get more airflow, I am interested in making a more robust and reliable unit as well.
Does anyone have a circuit for a 3 phase regulator rectifier that is capable of reliably dumping 300 watts?
Cheerio
Pete

Offline oztules

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Re: Motorcycle Shunt Regulator ?
« Reply #1 on: July 16, 2017, 07:16:33 am »
Epoxy is not too keen on heat guns being directed their way.... but I have found it very hard going digging into these things...... some have surface mount stuff in there that when you heat the gunk up hot enough, little silver bits come out with it.... leaving a circuit board with nothing on it... this does not help either.

Curious that it is a dump load  arrangement.... not sure what I expected, but that was not it.


................oztules
Flinders Island...... Australia

Offline Pete

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Re: Motorcycle Shunt Regulator ?
« Reply #2 on: July 16, 2017, 05:33:05 pm »
Thanks Oz, yes it is an odd arrangement but then the alternators are permag units. No way of controlling the rotor current or mangetization. So they just have a shunt regulator that controls the output voltage. Pretty crude eh.
I do remember that ancient triumph motorcycles had a large zener diode in a heatsink under the headlight. I am not certain but I believe that it was the regulator. Pretty crude too but obviously worked.
I have ordered a new regulator, and am considering making up a new one myself. My thoughts go to having a three phase rectifer separate and a regulator that can be mounted in a better place than under the seat. I guess I will see if moving the new regulator to a more breezy place is enough.
Thanks again.
Guess it is getting a bit cool on your little island.
Pete