Author Topic: Testing a Lucas 49072 Rectifier  (Read 317 times)

Offline A10 JWO

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Testing a Lucas 49072 Rectifier
« on: 11.04. 2018 17:38 »
Found a rectifier in one of my boxes, how can I find out if it works correctly. 12 volt Pos earth. Thanks.

Offline a10gf

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Re: Testing a Lucas 49072 Rectifier
« Reply #1 on: 11.04. 2018 18:12 »
Feed it with 12v AC, and measure if 12v DC comes out :O) Should be easy ...if having some AC source available.

Is it this > http://www.sparesforclassicmotorcycles1.co.uk/genuine-lucas-49072-positive-earth-rectifier-bsa-c15--ww10135-976-p.asp
am guessing the yellow must be the AC in.

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Online Bsareg

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Re: Testing a Lucas 49072 Rectifier
« Reply #2 on: 11.04. 2018 19:21 »
This looks like a selenium rectifier. Although it looks good cosmeticly, this type can age and become leaky. When new they were not as efficient as a modern silicon type. Ok for originality but not for reliability.
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Offline A10 JWO

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Re: Testing a Lucas 49072 Rectifier
« Reply #3 on: 12.04. 2018 15:40 »
Thanks lads, that looks like it. Will look into the more modern one, just spent a few shillings on a complete Boyer kit with dual coil and heatsink. Might as well go the whole hog.

Online chaterlea25

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Re: Testing a Lucas 49072 Rectifier
« Reply #4 on: 12.04. 2018 21:08 »
Hi JWO,
As you have bought the Boyer kit it would be a very good idea to invest in a quality combined rectifier regulator
Electronic ignition and old rectifiers / zerer's do not marry well  *warn*
Add extra earth wires from the headlamp and tail light to the main earthing point on the frame where the battery and reg are also earthed

John
1961 Super Rocket
1963 RGS (ongoing)

Offline A10 JWO

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Re: Testing a Lucas 49072 Rectifier
« Reply #5 on: 13.04. 2018 16:40 »
Thanks John, on your advice I did that this afternoon. I have fitted a new modern rectifier today, but will look at the regulators. Must admit it looks like the Starship Enterprise under the seat. May need a smaller battery due to possible lack of space ( that may be another thread. )