"Bob La Londe" wrote in message news:u74ham$3p6m0$1@dont-email.me...
I literally fixed the unit by picking a piece of trash out of the dirt
and stuffing it in there.
---------------------------
Congrats, you beat the System.
When I worked in the automated test equipment industry I learned how to
test components with a DC power supply. For caps I use a voltage and
current adjustable supply to apply a few milliAmps with the voltage
limit set to the cap rating. The voltage on a good electrolytic will
rise steadily and hold after the current is disconnected, DVMs usually
have a 10 MegOhm input resistance that will slowly discharge the cap.
The cheap HF DVM is 1 Meg. A bad cap will stall at the voltage where its leakage increases. The formula C=IT/V gives the capacitance when you
know the current and time to charge it. Degraded capacitors are pretty obvious when tested this way, plus reforming stored ones every few years seems to prolong their life.
This gives simpler methods that do the job but won't identify a marginal
cap as clearly. https://library.e.abb.com/public/79afb1796ad24a19bf2970771c6892e4/Guide_for_capacitor_reforming_Rev_G.pdf
Be careful to discharge the cap afterwards, and between testing the two polarities on AC motor caps.
The automated test equipment measured the component to determine if it
was within spec or not. It appears the ones that were slightly below
spec went to Radio Shack and more recently Amazon, at least that's what
my testing showed. Analog Devices sent us op amps that tested well above
spec to use in the production line testers we sold them.
Hand-held, battery powered meters generally don't apply a high voltage to
the Device Under Test, as it would be dangerous to the user. My high voltage >leakage tester produces the voltage with a hand-cranked generator, which >keeps both your hands occupied and off the test leads. Measuring the >capacitance at low voltage won't detect faults like leakage at a higher >voltage.
"Bob La Londe" wrote in message news:u757su$3rfhe$1@dont-email.me...
The little Ideal meter was a gift from my dad when I started messing
with 3 phase CNC stuff. He thought I might need to be able to read
phase rotation. I have never used it for that. I am aware that running some types of pumps backwards could destroy them, but a spindle is
faster and easier to check with the poor boy "run it and see" method.
This meter has a CAP test function and it seems to read okay.
Bob La Londe
---------------------
I looked up this Ideal meter to see how much voltage it applies to the
cap, but it doesn't say. https://www.elliottelectric.com/Media/61361-IDE-4-0-InstallationSheet.pdf
Hand-held, battery powered meters generally don't apply a high voltage
to the Device Under Test, as it would be dangerous to the user. My high voltage leakage tester produces the voltage with a hand-cranked
generator, which keeps both your hands occupied and off the test leads. Measuring the capacitance at low voltage won't detect faults like
leakage at a higher voltage.
An expensive professional high voltage insulation tester: https://www.zoro.com/aemc-instruments-hand-cranked-megohmmeter-1000vdc-6503/i/G3546541/?utm_source=google&utm_medium=surfaces&utm_campaign=shopping%20feed&utm_content=free%20google%20shopping%20clicks
My cheaper one: https://www.cncest.com/products/metal-shell-1000v-resistanc-meter-insulation-tester-insulation-resistance-tester-with-handle-shaking-test-of-various-motors?gad=1
By paralleling a DVM it will find capacitor (and motor) insulation
breakdown voltage, though its low output current charges electrolytics
very slowly. The built-in meter measures and displays the ratio of
voltage to current which equals resistance, but not the voltage itself. That's regulated by a centrifugal slip clutch on the generator.
I was lucky to be out sick the day some recently graduated electrical engineers tested the phase rotation on a large power supply next to
where I was working. I came back to a black stain on the floor and up
the side of the machine I was building, and never saw them again. It
seems they had been squatting beside the supply, touching the 480V
cables to the input terminals, and one slipped and touched a large DC electrolytic.
and a new dual motor capacitor.
[...]
On 6/23/2023 12:30 PM, Bob La Londe wrote:
[...]
Just to be proactive I installed a new contactor
and a new dual motor capacitor.
[...]
I hope that you gave the cap supplier an earful!!
and a new dual motor capacitor.
[...]
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