Ever notice your rectifier getting hot while running?
- Thread starter jimbo
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Yes also the later square potted bridge type ones without fins get hot too, but its normal.
It would be interesting to see what the spec was, I guess the penny pinchers decided they could do without fins when they made the bridge type, but silicon eventually fails and heat increases the aging process.
I have in the past had one fail on me, - it made a sticky mess.. worth carrying a spare if doing some miles.
It would be interesting to see what the spec was, I guess the penny pinchers decided they could do without fins when they made the bridge type, but silicon eventually fails and heat increases the aging process.
I have in the past had one fail on me, - it made a sticky mess.. worth carrying a spare if doing some miles.
You have to wonder how much ambient "cool air" there is under the seat, downwind of the engine and next to the oil tank with three quarts of hot oil
Tim Kraakevik
kraakevik@voyager.net
Tim Kraakevik
kraakevik@voyager.net
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Silicon and Selenium rectifiers were commonly used in old tube amplifiers where it gets far hotter than it ever will in the Commando. As noted, it's all completely normal for them to be quite warm...even hot. But, obviously if you are uncomfortable with it, a Podtronics is a good replacement. A 1973 rectifier was on mine until '12 with no problems at all. When I installed the Alton E-start I switched to a Podtronics, thinking it might be a better match to the Alton alternator.
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blacklav said:
It uses diodes to convert the AC from the alternator to DC. Though there is some heat produced, they are much more efficient (less heat) than a Selenium rectifier like the OEM Norton unit.
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blacklav said:
It might not get as hot but the Boyer instructions state;
http://www.boyerbransden.com/pdf/PBOX00108.pdf
The three-phase Power Boxes also have fins to help keep them cool.
https://www.rgmnorton.co.uk/buy/boyer-p ... r_1885.htm
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L.A.B. said:
The rectifier (before I replaced it with Podtronics) on on my '73 Commando is a Selenium rectifier, NOT silicon. The difference is very obvious: selenium rectifier plates are square, silicon are round.
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MexicoMike said:
Well, it was obviously an older replacement as it wasn't a standard OEM Norton Commando rectifier of any year, as the Silicon 49072 2DS 506 rectifier had replaced the Selenium type on just about all (if not all) British bikes by 1964.
http://www.classicbike.biz/Norton/Parts ... _73-74.pdf
Group 28, Item 31, 49072 Rectifier (2DS 506 Silicon).
http://www.classicbike.biz/Norton/Repai ... mmando.pdf
Section A Electrical
Section J4
(The '2DV 406' in jimbo's photo is the two-diode 850 Mk3 rectifier for the RM23)
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So somebody replaced a newer silicon rectifier with a much older Selenium rectifier? Certainly it's not impossible but seems very odd. One possibility - I don't know for sure - the bike had the 180W Lucas alternator and the dual zeners/"square" regulator. Perhaps the 180W "kit" included the older regulator? Not sure why that would be the case but maybe so...
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MexicoMike said:
Not that odd when you consider the 180W alternator wasn't original, and how many years old was the bike when you bought it?
I can't think of any logical reason why an obsolete rectifier would be supplied as part of a 180W alternator and dual Zener kit.
Just the usual cobble-up of odd parts by the sound of it.
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I just looked at the rectifier I removed back in '12. The part number is LUCAS 83536 It also says" Lucas England" and then what looks to be "3D55" but it's hard to read that part.
Additionally, LAB, you are correct, it is NOT a selenium rectifier! I remembered that it had square plates and therefore ASSUMED from memory that it was selenium but the (only) two square plates are the heat sinks, it appears to have diodes wired between the plates but it does not look anything like the OEM silicon rectifier in the pictures posted.
I bought the bike in '06 but it was essentially original - I guess the 180W alternator was added at some point but all else seemed (and was claimed to be by Baxters) totally original.
Additionally, LAB, you are correct, it is NOT a selenium rectifier! I remembered that it had square plates and therefore ASSUMED from memory that it was selenium but the (only) two square plates are the heat sinks, it appears to have diodes wired between the plates but it does not look anything like the OEM silicon rectifier in the pictures posted.
I bought the bike in '06 but it was essentially original - I guess the 180W alternator was added at some point but all else seemed (and was claimed to be by Baxters) totally original.
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MexicoMike said:
That's a three-phase RM24 rectifier (Silicon) +ve earth.
https://www.ebay.co.uk/p/Lu83536-Lucas- ... /502976006
(3DS5 83539 = -ve earth)
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