View Full Version : Generator Not Working

10-11-2012, 09:51 PM
So, I bought this 59 Tr3a last month. To drive it I had to constantly charge the battery as the generator was not working. Measured it's output with my Fluke VOM at 2000 RPM and it was zero volts. Looking for ideas I came across some BCF info referring to a "Control Box". I was surprised. A "control box" sounded like it might be a computer, but in 1959 computers were the size of semi-trailers so that was a little suspect. Then I remembered British terminology, like "bonnet" for hood, and "hood" for the convertible top and figured out the "control box" is the voltage regulator. Someone had already posted, maybe it was TR3driver in an old BCF post, said to remove the control box cover and gently press down on the two relays, one at a time. I idled the car at 2000 rpm and my youngest daughter sat in the driver's sat watching the amp gauge. When I pressed on the top of the left relay, as you face the voltage regulator, the amp gauge suddenly flicked over to +20 amps. That relay had been stuck in the off position. AHA!! I worked it up and down a few times watching it spark. Thinking the contacts might be oxidized, I looked for my point contact file but it was nowhere to be found so, I grabbed some 800 grit wet or dry sandpaper, (sorry) cut off a couple of thin strips and used them to burnish the contacts on the two relays. Now that generator works like a charm, thanks to this fabulous forum and the generous sharing of knowledge by it's members. Of course we immediately embarked on a top-down trip around the neighborhood testing all the lights and the horn and they all worked and the bright red generator light is finally off. Another great TR3 day.

Andrew Mace
10-11-2012, 10:30 PM

10-12-2012, 02:34 AM
Good deal!

In defense of British terminology though, I'd like to point out that regulating voltage is only 1/3 of the job done by the control box. It also contains a cutout relay and regulates current as well as voltage. So "voltage regulator" is something of a misnomer as well.

And it actually is an analog computer, sort of. It adds voltages and currents; compares the results (in one case based on temperature); and makes a decision whether to open or close the contacts. Pretty sophisticated, for being purely electro-mechanical.