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voltage regulator question

Posted: Fri Apr 03, 2015 8:31 am
by MikeB
Hi

Getting near the end of my winter project on my P2 10 1939 I have one last problem to solve which I hope some members can help me with, namely the RF91 voltage regulator on my car, this had been playing up just before I put here away for the winter

The unit was showing over charging on the ammeter, having studied the Lucas manuals on voltage regulators I have put this down to the cut out coil which is showing signs of overheating, I have looked out for a replacement but there are not many around, having looked at an electronic conversation @£185 or a reconditioned RF91 @ around £250 I called one supplier that said if it just the cut out you could replace that part only with one out of the more common RF95 or you could purchase a new control unit from Lucas today that will replace it, namely an RB106 which he says is basically the same unit
My questions:
Has anybody had experience with swapping out the cut out coil on a voltage regulator ?
Will the RF 95 be an alternative for the RF91 ? Lucas manual says that some are interchangeable but I don't know which
Does anybody have a RF 91 for sale at a reasonable price ?
And finally where would I purchase a new RB 106 if that would be suitable ?

Any help would be appreciated

Happy Easter to all

Mike
MikeB Posts: 83Joined: Mon Mar 17, 2014 7:23 pmLocation: Nottinghampshire

Re: voltage regulator question

Posted: Fri Apr 03, 2015 8:41 am
by 1938 P2 14

Re: voltage regulator question

Posted: Fri Apr 03, 2015 10:16 am
by luli
I have used RF95 successfully for many many years on my 1946 Rover 10. You can watch some pictures here: http://wp.me/pXLKy-28x
I have also tested It's electronic version, with good results, see here: http://wp.me/pXLKy-2hc
Finally, Stealth has released a cost effective alternator which is mechanically identical to the Lucas C45 dynamo. It offers many advantages over a dynamo, and you do not need a control box for it; So that for much less then an electronic box you can get a lookalike alternator.
As for myself - I haven't tested it yet.
http://www.accuspark.co.uk/dynamator.htm

Re: voltage regulator question

Posted: Fri Apr 03, 2015 1:20 pm
by 47p2
I have a Lucas RF91 lying in the garage I no longer have a need for and would like back what I paid for it a number of years ago which was £75.00 plus postage. Pictures available if you are interested

Re: voltage regulator question

Posted: Sun Apr 05, 2015 8:25 am
by MikeB
Thanks all for the advice , much appreciated, looking at all the options I think I will go with the
dynametor as this seems the most sensible solution based on cost and eliminating other potential reliability issues with the current set up, I may have to make some modifications to make one fit though as mine is a different model of dynamo , anybody had experience of fitting one of these dynametors ?

Thanks

Mike

Re: voltage regulator question

Posted: Mon Apr 06, 2015 3:21 am
by chris dancey
I fitted one to our MGB, brilliant, oodles of power ( 40 + amps ).

Re: voltage regulator question

Posted: Tue Apr 07, 2015 10:32 am
by MikeB
Thanks for the reply, do you think I will need to make up a bracket for the p2 to make it fit ?

Re: voltage regulator question

Posted: Tue Apr 07, 2015 10:59 am
by luli
Nominaly it has the same dimensions as the C45 dynamo.

Re: voltage regulator question

Posted: Sun Apr 19, 2015 1:05 pm
by MikeB
Hi there

I purchased a Dynametor and have started to fit it this weekend, my original one on the car was a C45 so the new Dynametor will fit using the existing brackets which is good, however when removing the pulley off the old unit it is not a match for the new unit, old unit shaft diameter is 17mm and new one 15mm, so the pulley can not be used on the new unit, they don't advertise the fact that a new pulley will have to be sourced in their advertising for the Dynametor so back to the drawing board

Question ; Has anybody sourced a new pulley for their conversion ? additionally, does the Dynametor require a cooling fan attached to the pulley ?

Any help sourcing a pulley and advice will be much appreciated

Thanks

Mike

Re: voltage regulator question

Posted: Sun Apr 19, 2015 2:57 pm
by luli
Call them and complain. The specifications in their web site clearly say:
"-Adjuster lug thickness. 8mm
-Mounting lug thickness. 10mm
-Distace between mounting lugs 165mm
-Shaft Diameter 17mm
-Amps Output 45A"
I too had a problem with them, they send me a C40 replacment instead of C45. I am still waiting for the correct one.