Broken Box Control LUCAS RF95/2 to LUCASRF 95/3

[JUANRAF]

Hi,

In my restoration I bought a new box control 9 terminals from Moss (141-900). worked fine only 3000 miles!!!

Now I have to buy a new regulator for my car. I'm not going to buy a Chinese reproduction.

My question is:
the reference of my control box is LUCAS RF 95/2 for my TC. I can install the reference LUCAS RF 95/3. ?

[Tom Lange, MGT Repair]

95/2 was the original-style 9-post box used on the TC and TD up to about car TD9000, and was also used on many other British cars of the time.

106/1 was the later 5-post box.

I don't know what the difference between the 95/2 and /3 is, but I do remember seeing that Holden in the UK sold 95/3 as a replacement for the 95/2, and a proper replacement for the TC.

Do be sure you get a 12V box, as they also came in 6V.

Tom Lange
MGT Repair

[JUANRAF]

I forgot to say that my dynamo is LUCAS C40L

[Ian R]

I gave up on my Lucas control box that is circa 80 years old.
The modern replacements seem to be very substandard.
I fitted a DVR3 solid state voltage regulator from England that is small enough to fit inside the existing Lucas control box.
It controls the voltage easily & the car looks externally the same.

Link is below:

https://dynamoregulators.com/documents/dvr3-data.pdf

[Steve Simmons]

It's easy to replace the guts with original guts, just using the outer case of the reproduction. Or buy a used regulator for not a lot of money. I found one at a swap meet recently for around $50 needing rebuild. You can use the coils from a cheaper RF106. There are places to send them to get rebuilt and calibrated. One of them is British Auto Electric in California. I think it costs around $100 and it comes back good as new, if not better.

I haven't run a replacement RF95 or 106 but have run originals of both for many years with no trouble.

[cdrolshagen]

HI,
had the same problem, fitted a new repro 9 post control box,
first worked perfect - charging around 14 V,
after several 100 km - the ampere gauge shows full 20 A and the engine stalls,
after half an hour could start the engine again - checked the voltage output,
more than 20 volts, and the engine stalls again after minutes, the coil was very hot.
The next day an other try, the same.
In the end I fitted an electronic regulator in a existing original Lucas control box,
works well since.
Cheers Carl

[Tim Jackson]

I used this UK company to convert a RF91 regulator to solid state:
http://www.dynamoregulatorconversions.com/
New replica electronic RF95 regulators are available from this and other suppliers, including FTFU:
https://fromtheframeup.com/products/el4 ... b975&_ss=r

[i.thomson]

I believe the /2, /3 refers to the current limit that they are set to. You would have to refer to the Lucas literature to find out what the actual setting are.

Ian

[JUANRAF]

Hi,
I will install an electronic regulator inside the control box.

I think it is the best idea. I want the car to work well.

I leave the super original for others.

It's great to have the help of all of you.

[Duncan M]

Several years back the group convinced me to stick with the original unit. My car actually has the original, original unit. They can be a bit fiddly to get cleaned up and gapped correctly, and adjusted for cutout voltage and the voltage the unit will ultimately charge the battery to. I run lead/acid batteries, but they can be adjusted for the best voltage-- whatever type of battery you choose to run. I also run the original 11 amp dynamo.

What can destroy the vary rare dynamo in the TC is a battery with one dead cell. If you use the electronic version the regulator will ask too much from the dynamo to keep the battery up to whatever voltage it is set for. In other words, an electronic version will ask for higher and higher voltage to get a high enough amperage flow to try and keep the battery at 13.5V or whatever it is set at. Electronic version will peg the output of the dynamo to try and keep a failed battery charged.

With the original version, the max voltage (and therefore the max amperage) is limited to 15V (or whatever you set the cutout at). In other words, a battery with one dead cell is not fatal to the dynamo when using the original voltage regulator, but it can be fatal to the dynamo using any of these electronic jobs.

[Steve Simmons]

Well now that's interesting. I've never heard of this issue before.

[DaveAhrendt]

I don't know if that's the case with other solid state regulators but the one we produced would not let that happen. The output of the generator is constantly monitored by a Hall effect current sensor. Regardless of the voltage state of the battery the regulator sensed the current and if over maximum it would reduce the field drive until the current dropped. It monitored at a rate of 30 times per second so it didn't take to notice and correct an overcurrent condition.

The maximum current level was built-in to the regulator firmware as requested by the owner and generator type. We supported generators from 11 to 35 amps.

[Duncan M]

Running the original TC 11 amp dynamo at maximum output of 9 or 11 amps constantly is not doing it any favors. Will greatly shorten its lifespan. One of the reasons people choose LED headlights is to keep the current demand as low as possible on the dynamo.

Same problem will happen in a completely modern car's electrical system when you have a battery with a dead cell. It will constantly charge the defective battery, keeping the good cells slightly overcharged such that it will start in the morning and appear all good. People only figure out the battery is defective when the (60 amp or whatever alternator) gets cooked and no longer charges the battery at all, and the car will not start.

Only common test that will reveal a battery with one dead cell is a proper load tester. Of course you can also visually inspect each cell for bubbles, while charging with a manual 6 amp (or whatever) charger. I have had very sophisticated electronic chargers that will not usually catch a dead cell -- and not always throw a fault code.

If you keep the Lucas buzz box, and have it set up properly, along with the 11 amp dynamo, a dead battery cell will reveal itself by the battery not having enough current to start one day. ie load testing.