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View Full Version : TR2/3/3A The TR3 Bouncing Ammeter Gauge?



karls59tr
01-03-2010, 09:12 AM
Mine bounces back and forth...always has. I'm assuming that this is normal as they all seem to do it. Anyone have one that dosn't? Is there a fix?

TR3driver
01-03-2010, 09:37 AM
Some bouncing is normal, under some conditions. Basically, when full output from the generator is only slightly more than what the regulator wants, the regulator contacts open and close slowly enough to see on the ammeter (switching the generator from full output to minimum output and back). There is a certain frequency where the needle becomes mechanically resonant and starts swinging wildly (far more than the actual current change). But a small change in engine rpm should stop the bouncing as the contact action moves away from the resonant point ... at driving rpm it should be too fast to see at all.

Changes in electrical load, like stepping on the brakes, will also cause the ammeter to jump (this is one way to check if your brake light switch is working). Turn signals also, of course.

But if you are seeing bouncing that cannot be explained by the above causes, you've got an electrical problem of some sort.

Converting to a solid-state regulator would reduce the bouncing; as would using an ammeter that reacts more slowly. Seems like a lot of work though, to correct something that is "as original". However, I've been toying with the idea of a solid-state regulator for a different reason; the stock regulator just does a lousy job of regulating voltage (due to it's 2-bobbin design). A solid-state conversion (or even a 3-bobbin mechanical as used on some other Triumphs) would be able to charge the battery with the headlights on; without over-charging when they are off.

angelfj1
01-03-2010, 10:41 AM
However, I've been toying with the idea of a solid-state regulator for a different reason; the stock regulator just does a lousy job of regulating voltage (due to it's 2-bobbin design).

Randall,et al, you might want to see this:

Solid State Voltage Regulator (https://www.mgaguru.com/mgtech/electric/et232.htm)

tinman58
01-03-2010, 11:42 AM
So cool, I will be sending mine off as soon as my replacement comes in from TRF. I wish I knew this before I ordered a replacement. O.K. so now I have a spare.
Solid State Voltage Regulator

angelfj1
01-04-2010, 04:03 PM
Dan: Please keep us posted. I am really interested in this upgrade.

Thanks,
Frank

MGTF1250Dave
01-04-2010, 08:19 PM
Aloha Frank,

I had that conversion done early last year. It works great in my TR3A and unless you remove the regulator cover, you can't tell the difference between the original or the conversion.

angelfj1
01-04-2010, 10:11 PM
Aloha Frank,

I had that conversion done early last year. It works great in my TR3A and unless you remove the regulator cover, you can't tell the difference between the original or the conversion.

Dave:

Great! Just what I wanted to hear!!!

Thanks