Jump to content

Will This Work?

robin craig

Recommended Posts

ok chaps, can I substitute the following?


We have a generator No 12 Mk 8 marked as FV 546174 it has a greasable bearing at the snout.

This unit has a problem with the threads.


I would like to substitute it with a No 12 Mk 1 marked as FV 546183 no greaseable bearing


both are rated at 28.5 volts amps 140 1000rpm rotation reversible.


the application is a CVR(W) Fox



Link to comment
Share on other sites

Robin I have the EMERs for Mk 1, but can find no reference to Mk 8. Even the detailed EMER index published in 2003 still only has reference to Mk 1.


Very often in these alternators, the diodes become obsolete & the only diference between Mks is a newer diode type. But maybe here it is an improved lubrication system as well. Looking at its circuit diagram there doesn't look too much that could change other than the diodes. Given that the two Mks have identical power ratings, it certainly looks tempting to try.


If the Mk 8 seems electrically ok you could compare pin wiring & resistance readings with the Mk 1, to check it is safe to try. There is some coverage of the Mk 1 from page 16 on here:




You may well have the NSNs but just in case:


FV 546174 2920-99-815-6073

FV 546183 2920-99-114-7507

Link to comment
Share on other sites



As always, your response is technical and excellent. I had a look at the link and found the information highly interesting but also highly technical and for the most part beyond my electrically challenged skill level. Im afraid im a mental midget in this department, it either works or it doesnt.


The substitute is a CVR(T) take off unit purchased from the UK as such and given the blessing of "tested and working" by the seller and he is a good guy in my books so I have a level of confidence that it is a good one.


I have done a side by side comparison and apart from the lack of a grease fitting to the bearing they are for all intents and purposes the same.


I think seeing as how restoring the knackered thread is a pain I will likely chance it and swap them over.


I have enough work to fabricate properly the mounts for it without adding to that by having to deal with the thread issue and leave it for another time.


Many thanks, I will advise as work progresess.


many thanks, your electrical mental midget,




Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...