Does anyone really understand how the generator/voltage
regulator/cutout system works? I mean REALLY, like you can explain it to me?
A couple of weeks ago, the charging lamp began staying on after
starting Sarah (TR4A). I poked around under the bonnet, and discovered
that if I put a test lamp between the D terminal on the regulator box
and ground (I was trying to see if the generator was generating), the
lamp would glow dimly. By revving the engine, the lamp would glow more
brightly, then there would be a click and the test lamp would stay on
bright, and the charging light went out.
Sometimes the charging lamp would go out by just revving.
After a couple of days, this became the norm, and I stopped carrying the test
lamp.
A few weeks went by - now I'm back in the situation where I have to put
a lamp on the D terminal to ground to get the cutout to pull in. I
tried adjusting the spring tension (probably a bad idea) to no avail.
The last time I tried this, today, the cutout didn't pull in, and the
charging lamp stayed on.
I'm most suspicious of the generator. But I'm trying to understand what
the failure mode is that covers the above circumstances. I could almost believe
that
the shunt coil between the regulator frame and ground is open, and the lamp is
serving the same purpose - I haven't taken the regulator apart yet to determine
if that's so. I also haven't checked the generator with the leads disconnected -
probably should have done that first!
|