Regulator getting hot

[Mark McCombs]

Should my voltage regulator get hit to the touch during normal running?

Odd question, but maybe someone could put a hand on theirs while the engine has been running a while; I'm finishing up my restoration but don't want to venture too far if this us a potential hazard.

Thanks

[Rob Reilly]

No, it probably means your contacts are stuck closed, or some of the electrical connections are corroded.
It's trying to pass too much current through a small contact area or a corrosion resistance. That's why it gets hot.
Some people solder all those rivets on the back.

[Steve Simmons]

I agree. Warm perhaps, but not hot. Clean the contacts and if it doesn't clear up then have it calibrated.

[Mark McCombs]

Ok, thanks.

Is there a way to check functionality with a 12v power supply?

[Steve Simmons]

These might help:

http://www.mg-tabc.org/library/lucas_check_charging.pdf

http://www.mg-tabc.org/library/lucas_ge ... _tests.pdf

[Duncan M]

Mark-
Keep in mind there were several bobbin designs over the years, and that is just on the real Lucas boxes. Between the info sources available online you should be able to get the correct settings for whatever specific design you have.

I rigged up an old laptop power supply I had not thrown out, 18 or 20 volts or thereabouts. Got a digital volt indicator soldered in the gadget and used a very inexpensive PWM or DC motor speed control (Ebay still has them for under $8) to dial in a specific voltage of 16 volts or whatever. Whatever voltage the literature talked about. Turned out the settings I had found online for my original date stamped Lucas box were very close to the voltage cutout settings, etc that are given in the literature. In other words I got very close-- going by the gap settings.

After the car was up and running I started observing the battery voltage when I would get back from drives, and I ended up lowering the charge voltage just a bit. That was years ago, and I have not touched the box since.

Like most people, I have a battery cutout device so juice is cut off when the car is not in use.

[Mark McCombs]

Thanks for the tips.

One thing I'm wondering, since I assembled TC8126 as a project and wired the harness from scratch, is that their could either be a short or a wire crossed that is resulting in the hot regulator.

Everything electrical functions, I'm thinking it may be one of the accessory terminations.

Ill clean the regulator, ensure a good ground and see what happens first, then maybe start with disconnecting one accessory at a time.

[Duncan M]

If not adjustment, it sort of sounds like it could be poor grounding. Either where the battery connects to ground, or the wire (or wires) used to ground the regulator at connection "E" and wherever you terminated that wire(s) on the chassis.

If it was the cutout points sticking shut on a car with battery connected, I believe the regulator box would heat up as well as the dynamo. The few insulated wires inside the dynamo would start melting and give off a special odor.
1. In normal driving, on a TC, the dynamo case should not get much hotter than a properly functioning ignition coil.

[Mark Strang]

Duncan,
You mentioned that you have a battery cut off switch on your TC. Where did you locate it?

Mark

[Duncan M]

Mark-
Just on the battery.
Duncan-

[Mark Strang]

Okay. I'll thought it might hit the top cover but apparently not. Thanks,

Mark