Ralph Mowery
k.net Tue, 04 Apr
2017 17:15:24 GMT in alt.home.repair, wrote:

You probably will not find a voltmeter/multimeter that goes over
around 1000 volts. Or not at a reasonable price for most.

Has to be one. obviously. Otherwise, various companies would have no
way of reliably testing their HV output devices to ensure it is
providing enough juice to energize neon and/or a magnetron tube.

I'm looking for one thats hand held and doesn't require being pushed
around on a cart due to it's own weight. Reasonably priced. By that,
I mean less than say, 2 grand or so. I couldn't justify anything more
than that for the times I'd have use for it.

To go over 1000 volts you will need to get a high voltage probe.
That converts the common meter to read a higher voltage. I think
Fluke has some good to about 6 KV for just under $ 100 and some
good for 30 or 40 KV for over $ 200. Lots more than I want to
spend to check out the few things I have that will do over 1 KV.

Understood. Like I said, I don't do much with 1+kv on a daily basis
or anything, but, it would be nice to acquire an accurate reading on
the display.

I would not buy a used probe for that kind of voltage. Once you
get much over 1 KV things that should be insulators seem to want
to arc over.

It's not the insulators directly at fault, rather it's the airgap and
how far the voltage can jump it. The voltage does not need to be 1kv
or more to do this, either. You can get an airgap jump with a 240volt
water heater, too. Just make sure it's under load, preferably with
both elements fired up. Take the wirenuts free, and connect a
mulimeter to them to take a reading. Now, slowly take the probes off
the wires; An arc will form going from each wire you were reading
from to the probe attached to it, until you pull the probe far enough
way where the arc can no longer follow. It's nowhere near 1kv, it's
only 240 volts, but, as the water heater is running, it's 240volts
under load vs just being present on the line. The arc will try to
keep the connection between each wire you tested and the probe that
was previously touching it.

When you're dealing with voltage without amperage behind it, you need
more volts to make the airgap arc jumping effect. IE: neon sign power
supply. A typical neon sign power supply can jump approx 2 inches
from the contacts feeding the tube. So it can shock you without you
actually touching the connections, two inches or so before you
reached the connection point itself.

Obviously, the higher the voltage, the further it can jump. Which is
why a simple power switch isn't going to do **** in a lightning
storm. As the lightning storm has a high voltage level AND a ****load
of amps behind it too.

It's also why the devices that blow to seperate your mains because of
a surge may not be as effective as you might think. If the incoming
voltage is high enough, it's going to jump across the break and re-
establish the connection until the juice is gone OR it's burned off
the connection points enough with the arcing that it cannot remain
established.

While the connection is by no means a stable one in these situations,
it is a connection and power is flowing (even for a short period of
time) into your panel and anything connected to it, even if the
breakers are set to the off position. It's just arc jumping those
open points too.


If I want to get an idea of a bad transformer I use a varac to cut
the primary voltage way down and bring it up slow to the meter on
the secondary gets close to 900 or so volts. Then do the math to
see if it is reasonable.

While I understand where you're coming from, that doesn't take into
consideration a failing transformer. While it may have little to no
trouble delivering 900 or so volts with/without a load present, it
doesn't mean it's actually still capable of delivering say the 5kw
with or without a load present. Which is why I'd be interested in a
meter with the high voltage probes to check it while it's inline with
the circuit it's supposed to be providing power to.

I can see if it tries to drop out under load with that. Or, if it
tries to drop out under no load getting closer to the output it's
supposed to be supplying. As I'm sure you know, transformers can get
weak due to the insulation failing in the wrapping and it may not
show any signs at lower (for it) voltage levels. But, as it gets
closer to the expected output, the weakness can show.

I have also used a 6 volt transformer in the same way .

Yes, and, like I said, this doesn't really help for the above stated
reasons. The math may be perfectly sound, but, it's making the
assumption that the transformer has no issues and is delivering what
it's supposed to be. Without it being tested with a meter capable of
reading the higher voltages, one cannot be sure.


--
I would like to apologize for not having offended you yet.
Please be patient. I will get to you shortly.