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
Those selenium rectifiers...
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Very good Ian
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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Lucas rectifier
Thanks Ian and Alan .
Very informative and quick.
Ride safe, keep well.
Cheers Mick
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Here you go…
In answer to your question, here are some instructions that you can follow to test your rectifier:
https://granttiller.com/testing-your-motorcycle-rectifier
The £5 resin encapsulated ones are a superb substitute, as already pointed out. And no one will think any less of you for doing the swap.
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Dont forget to fit the new…
Dont forget to fit the new rectifier with an alloy heat sink .
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I've never bothered..
.. 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 …
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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I had 2 fail...
... 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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But what spec where the rectifiers?
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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I only used...
.. 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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... 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.