George Murhpy wrote:
I also calibrated my gas gauge to truly read almost empty at ``E'' and truly
full at ``F'' - it can be done....
*** George, you have my utmost respect. I messed with the
gauge in my `A, and was unable to get it calibrated. Care to
share the secret with an admiring public?
That gauge is an interesting piece, BTW. It has no springs
in it. Instead of a return spring, it has a coil that
provides ``return magnetism''. And another coil that charges
the magnetic pole piece. And, if I remember rightly, a third
coil that charges the stator that the pole piece pushes
against. Since the ``return force'' is electromagnetic, it
weakens when the battery is low. But so does the forward
force, so the gauge should in theory be insensitive to changes
in battery voltage. Therefore, no separate regulator unit is
needed. Also, when you reverse the polarity, all three coils
reverse their magnetic fields, and the gauge still deflects
up!
But calibrating it is a *pain*. There are two coils that
ride in slots in the case. You adjust it by moving the coils
back & forth in the slots. Adjust one too far, and the needle
slams the opposite way. I had to take mine apart because it
had a broken wire inside.
I think it would be possible to do a reasonable calibration
job if one had an external test set. Anybody out there know
what the resistance of the sender is at each end of its travel?
- Jerry
--
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* Jerry Kaidor jerry@tr2.com, jkaidor@synoptics.com *
* KF6VB *
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