S3 E-Type


by Dave

The BUTEC alternator is of a design made under licence from Leece Neville of the US. It's original application was for truck use, so it's a heavy duty & very long-lived design. The main rectifier diodes are housed in finned heatsinks inside the casing, whereas the field diodes are in a smaller housing on the back of the alternator.

Here's a picture of one of the rectifier heatsinks, the diodes are embedded at the bottom. I have heard that the diodes can be replaced in these blocks, but don't know where the diodes can be sourced.


Below is the basic electrical diagram of the system. The regulator is external and is also a Leece-Neville design, see details here.


Alternatorrichard|02 Jun : 09:46

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trying to workout what the green thing is between the two blue insulation blocks in the above picture. My one must be faulty as another has been added externally,what does it do and can I get a new one.

Re: AlternatorAdministrator |29 Jun : 08:12
Comments: 13

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Hi Richard,
I think it's some supression capacitor?? not sure it's meant to be green...that's just 30 years of corrosion...
it's not on the circuit diag....

Re: AlternatorAnonymous|06 Mar : 05:03

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Is is a capacitor, it says 0.15/250V/312M on it. In my Butec one leg of the capacitor was broken off, so I am at sourcing right now. If anybody has a good source, any help appreciated.

AlternatorKevin|30 Mar : 16:57

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Dave, did you ever manage to track down the source of the rectifier diodes? I believe these fail and are the main cause of charging problems.
great website a really usefull resource for the S3 owners.
Thank you Kevin

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