I worked out a few tests, but some of them involve having a variable DC
power supply on the bench. (No, a battery charger will not do unless you
have parts and know-how to build a simple variable supply from it.)
With just a DMM available, I would:
1) On Ohms x1 scale, short the leads together and note the reading.
Subtract this value (typically around 0.7 ohms) from the other readings.
1) Check resistance between terminals D and F. Should be less than 1 ohm.
If not, the problem is very likely burned contacts, so clean them, set the
gaps, and try again.
2) Hold down the armature on the regulator relay (the one with the adjusting
screw for the upper contact) and recheck resistance between D and F. (If
you need both hands to check the resistance, you can slip a piece of paper
into the contacts instead of holding the armature.) Should be around 63
ohms. Release armature (or remove paper), check that resistance reliably
goes back to around 0.
3) Check resistance between A and A1. Should be very close to 0.0 (after
subtracting the offset mentioned in step 1).
4) Set meter to highest resistance range available, check resistance between
D and A1. Should be over 20 megohms, which exceeds the range of most meters,
so you will see the maximum reading or sometimes "E" or similar.
5) Set meter back to x1, connect it between D and A1, then hold the cutout
relay closed. Resistance should drop to very close to 0.
If you do have that variable DC power supply, connect it between D and E.
6) Start with voltage set below 8 volts and slowly increase it. The cutout
relay should move (contacts close) between 12.7 and 13.3 volts. Continue to
increase, the regulator relay should move (contacts open) around 16 volts.
7) Now slowly lower the voltage, the regulator should close before 14 volts
or so (this value isn't specified in the book). The cutout should open
between 10 and 8.5 volts.
These tests are NOT a substitute for checking the regulated voltage when
operating with a generator (on the car); but they do functionally test each
part of the control box.
-- Randall
> I have one of those old voltage regulators out of a TR3
> sitting on my bench. Anyone know how to test it?
>
>
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