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Lucas rectifier

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Evening folks.

Can any one help me please?. I have searched the Forum but can not find out how to test a Lucas 47132 Rectifier as fitted to my "99 Dommi". 

If my rectifier has reached the end of its life can any one suggest a replacement?

Many thanks, ride safe and keep well.

Cheers Mick

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... were unreliable at the best of times. I'd replace it with a modern solid state bridge rectifier as supplied by our own Al Osborn and others.

If you really want to test it, use a digital multimeter set to resistance. You should get continuity from each of the AC connections to the positive connection and from the negative connection to each AC connection. You should get open circuit for each of those in the reverse direction.

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Very good Ian. A reasonable quick answer to the awkward question to testing rectifiers.                Of course the 47132 is selenium, dodgy at the best of times. The real answer about testing it is 'throw it away'. Buy a silicon. See aoservices.co.uk or phone.

For testing any rectifier (mostly all the same) you learn how to use a multi-meter on ohms, but it can be fraught with trips using multi-meters. Some understanding of basic electricity, is a good start.

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Thanks Ian and Alan .

Very informative and quick.

Ride safe, keep well.

Cheers Mick

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.. with a heat sink for a rectifier (as opposed to a regulator) as it doesn't dissipate much heat. Zener diodes on the other hand.....

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Perhaps I have been unlucky ,my last two  melted .  I now have a heat sink.  I do have a RM 23. and run with daytime lights.

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One wonders where you got these rectifiers from? They should always be mounted on some flat metal surface, bottom of a tool tray is a good start (on a Featherbed). I have never had an issue with the ones I sell, since the mid 1970s.

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... on my Commando, one in the depths of France. It was the day before my return ferry so I got a local garage to charge the battery and made it back the 250 miles or so with one interim charge. On disembarking the ferry at Portsmouth I sat outside the Maplins shop in the high street till they opened so I could get a replacement.

I think that the cause was an intermittent open circuit in the alternator stator sending high voltage spikes. In any case a replacement stator seemed to remove the problem.

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As I have said there is lots of variation with these things, the fact that it came from Maplin does not mean a thing. And certainly any staff at Maplins wouldn't have a clue.

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.. Maplins as there was a shop near the ferry terminal and I still had 150 miles to go before I was home. If I remember correctly it was 400 volt 35 amp rating but it was over 20 years ago......

I agree about maplins staff but they were always quite handy shops for odds & ends.

 


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