New Digital Megger

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Hand crank meggers have one advantage over digital ones. I have a Biddle digital megger. The digital display started fading out, and now it is impossible to make out the numbers displayed. However I got two decades of good use out of it, so I am not complaining.:wink:
 
zog said:
THose are nice, saw them at the conference this spring. Welcome to the forum, good to have another NETA guy around. You work for Charlie?
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Thanks for the welcome. No, I left AET almost 10 years ago, too much traveling, no time for family.

Working for small testing company out of Boston area.

I love the Hioki 3455, after coming off a 5KV Biddle crank I am spoiled. It will display leakage in megohms or amps whichever you select.
 
Displaying amperage was my point. Hi-potting shows current leakage. Megging shows difference in ohms/resistance. I'm interested in the design of this equipment.
 
We were digging through some old equipment here and came across a AEMC 1040 megger. Although this unit is only an 1000V unit and will not test our 5kV motors correctly I was going to use it to test LV motors and cables.

The only negative I see with this unit is that is max's out at 2000 Mohms (2 Gig). Is this max considered low? Any other feedback regarding this unit. I still believe it would be better than our analog crank meter.
 
mull982 said:
We were digging through some old equipment here and came across a AEMC 1040 megger. Although this unit is only an 1000V unit and will not test our 5kV motors correctly I was going to use it to test LV motors and cables.

The only negative I see with this unit is that is max's out at 2000 Mohms (2 Gig). Is this max considered low? Any other feedback regarding this unit. I still believe it would be better than our analog crank meter.
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2G is fine if you are just looking for a pass/fail result on LV equipment but 2G is very low to build and valuable trending data for predictive maintenence purposes.
 
76nemo said:
Displaying amperage was my point. Hi-potting shows current leakage. Megging shows difference in ohms/resistance. I'm interested in the design of this equipment.
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A megger is also measuring leakage current and doing the math for you and displaying resistance. You cant measure resistance.

What design questions do you have for what specific equipment?
 
zog said:
A megger is also measuring leakage current and doing the math for you and displaying resistance. You cant measure resistance.
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I understand that both a megger and Hi-Pot can measure leakage current and calculate resistance. Why are resistance units used for reporting results with meggers, while leakage current is primarily used for reporting units when Hi-Potting?

zog said:
What design questions do you have for what specific equipment?
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For a megger or Hi-Pot to put our a very large voltage with very little current I'm assuming that these devices have a very large output impedance which is what limits the current?

I have seen some short circuit current ratings listed for some particular devices. Is this rating the maximum current that will be supplied by the unit when it is put up against minimal resistance or a short? I have also seen normal output current ratings for devices. What are these output current ratings?

Are there any distance limitations when using meggers or Hi-Pots in regards to the amount of resistance which the device can push voltage or current thorugh?
 
I have seen Hi-Pot readings presented in both Mohms and leakage currents results, but most of the time in leakage current. Not sure exactly why.
 
mull982 said:
I understand that both a megger and Hi-Pot can measure leakage current and calculate resistance. Why are resistance units used for reporting results with meggers, while leakage current is primarily used for reporting units when Hi-Potting?



For a megger or Hi-Pot to put our a very large voltage with very little current I'm assuming that these devices have a very large output impedance which is what limits the current?

I have seen some short circuit current ratings listed for some particular devices. Is this rating the maximum current that will be supplied by the unit when it is put up against minimal resistance or a short? I have also seen normal output current ratings for devices. What are these output current ratings?

Are there any distance limitations when using meggers or Hi-Pots in regards to the amount of resistance which the device can push voltage or current thorugh?
Click to expand...

For example, in the HIOKI specification that Zog posted, what does the "measurement current" "leakage current" and "short circuit current 2mA or less" refer to?
 
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