Thread: Lucas crap........ oops!

Originally Posted by series1buff

Is there an auto electrician out there ?

The RF 95 junk regulator was a standard fitting on myriad Uk cars from the late 1930's to mid 1950's , from MG TC's to Morris Oxfords. They don't last that well with age .

I have one here that has every fault you can imagine. The field resistor was high.. I soldered in some more resistors across it . It now charges Ok, but the cutout is very uncertain of what it wants to do. On the test bench, with a variable supply, it cuts in at about 9 volts .. no adjustment will change its behaviour. I suspect its got shorted turns internally. When its in the car, it won't release or open at idle .. it's stuck on .

Any ideas

BTW new production repro RF 95's are availabe at 95UK pounds.

Mike

It could be as you suggest shorted (intermittently) turns, but I would inspect it very carfully to make sure that the armature is moving freely, and not getting partly stuck (I can't visualise how it could, but then I don't have one in front of me - perhaps something sticky on the stop it is released against).

Failing that, I would try and get hold of another old one and start from there!

(my 2a now has a S3 alternator)

John

Originally Posted by series1buff

....... I suspect its got shorted turns internally. When its in the car, it won't release or open at idle .. it's stuck on .

.....
Mike

Adjustment procedures are given in the S2a workshop manual - I presume they are also in the S1 manual, and you are following them. Note that if the idling speed is a bit high (should be around 500rpm), the cutout will not necessarily operate when idling.

John

If this is what I think you are discussing, it was one of the few items made by Lucas that were almost totally reliable and maintenance free. Have a look around old wreckers or swap meets. Should not be hard to find a good one.

thanks for your suggestions

After reading my old Auto elect. book I learnt a thing or two. The cutout has 2 coils .. the voltage coil ( shunted across the gene output) and a current coil ( in series with the battery/gene circuit) .

The current coil is in series with the battery .. it is the heavy gauge coil on the outside of the bobbin. It is supposed to help the cutout to open: when the gene voltage falls below the battery voltage , a reverse current flows through the coil .. this is opposite in polarity to the voltage coil underneath it... it throws the contacts apart . It also performs another job.. in the relay closed mode, its field is the same polarity as the voltage coil - they add together, providing a strong pull on the spring...stopping the contacts from vibrating . Clever.

Oh well . Read on .

Mike

These regulators are usually available reasonably cheaply at swapmeets. If yours is too hard to repair, get another one. I still see them quite frequently at wreckers also.

Aaron.

G'day series1buff

The master parts book listing for the Series2/2a Positive Earth regulator gives:Lucas No LU37182/Rover No R235553 for the C39 gene
and LU 37290/R514734 for the C40 gene you can also use the RB 310 type from later 2a's or the RB340 from the Negitive earth Suffix "D" models if you go Neg earth, but most people fit Bosch internal reg alternators, or external type with the RE55 reg hidden in the empty lucas reg box



You may be able to source a new Reg from Kevin Baker at KB classic spares in Qld (07)54944 221 or Barry Cliff at Wyong NSW (02)4351 1968,I hope that is of help.

cheers

Thanks for the ideas and suggestions .. I think It's working OK now. There wasn't enough tension on the spring that sets the cut in voltage. It's now cutting in at around 12.5 Volts.

BTW I always wondered why these mechanical regulators are polarity dependant , after all they work by magnetic fields .. so in theory they should work either way .. neg or pos ground - it shouldn't matter which way the fields are orientated . The reason is: apparently, the contact points are the probelm.. they are designed for a certain polarity , if you reverse the polarity, the points wear out very quickly.

I drive a vehicle (every day) that was originally positive earth which is now negative earth, and I have never had any problems with the points. I set it up about four years ago and it has worked fine since.

Aaron.