On Sun, 22 Aug 2010 09:33:03 -0700 (PDT), "Aaron Eel (Ehrin)"
wrote:


Need to check motor
currents against nameplate while it is running to determine condition there.

Sounds like the well service people are in your future.

I have no well, no pump, and can barely picture, problably
inaccurately, what the whole picture looks like. But I know parts and
circuitry in general.

How do I check the capacitor? I don't see how you can get a tester on
it. It's inside that little steel box and inaccessible unless I open
it (thereby disconnecting it).

How do you know you have one if it's inside a steel box that you
haven't opened?

Do you mean the rounded steel box (rounded on four corners, flat at
each end) that is the outside of the capacitor? If you open that, you
won't just disconnect it, you'll destroy it.

Logic would dictate that I check to
see if 200 volts is exiting that box but the lines disappear down into
the well. I could just buy a new capacitor but they’re 40 bucks.

If you're going to install a new cap, you first have to remove the old
one. So it will be disconnected and easy to measure**. What I do to
check a cap is use an analog meter, with a needle, not a numeric
display, and first I set it on voltage to see what its voltage is. If
it is more than tiny, that alone indicates it is holding a charge, but
is it as much as it should be? You should discharge the cap through a
resistor, so it doesn't all go out suddenly, but if it is too large a
resistor, it will take forever to discharge.

I I guess I've never had a cap that was still charged when I had cut
the wire on one end. But I haven't done this with 240 volt caps, 110
at the most and usually almost entirely discharged from sitting in the
tv for a while before I get around to testing it. So I set the meter
on ohms, and watch the needle. If the cap is good, it will go far to
the right at first (the very right is zero ohms) and then gradually
move to the left as the cap fills up and the voltage in it is opposite
to the voltage of the ohmmeter, and getting higher. When the needle
stops moving, there can't be more than 9 volts in the cap because
that's the value of the battery that powers my ohmmeter. So I reverse
the leads and again the needle moves all the way to the right, even
farther and faster that the first time if the the cap was not charged
the first time, and again moves slowly to the left as the charging
rate (from the ohmmeter) decreases.

I've never actually identified a bad cap this way, but that's not
surprising since I was testing caps that probably weren't bad -- I was
only testing to be sure -- and I don't claim the test will always
identify a bad cap, but if there is an open, the needle will always
show infinite or very high resistance. If it's shorted, it will always
show low or maybe zero resistance. These are the two most likely
problems.

You could also perhaps test any new capacitor in the store before you
leave the counter, and if they see you're only using a meter with 9
volt battery, they'll know you can't damage the cap.

AT THE VERY LEAST, I would test the cap this way before installing it,
so that you'll know what the readings are when brand new. So you can
see if shows anything different from the cap you are taking out. If
it's basicially the same, far to the right then slowly back to the
left, I'd figure the new cap is no better than the old cap.

Maybe you should write all the readings down so that if you ever have
to remove the NEW cap, you can measure it again and see if it is any
different.



**There are meters that are supposed to measure capacity when the cap
is in the circuit, but they're either expensive or you'll never use
them again. I don't think well repairmen have them.