Fluke Meter

Senior Member
Hi Guys,
How does a Fluke meter work when measuring insulation resistance? Does it apply a certain test voltage and measure the return current to calculate the resultant resistance value? Looking through the Fluke 1587 specs, I see that "output" voltage on the meter is up to 1000Volts. How can that be? The Fluke meter uses (4) AA type batteries - how can it generate such a high voltage? Would 1000V be the maximum voltage that the meter is designed to measure?
Thank you for your feedback.

tom baker

First Chief Moderator
Staff member
I didnt trust that type of fluke insulation tester over using a hand crank meager. But once I used the fluke, and it was a DVM as well, the meager was put on the shelf
How does it work? Likely a dc to dc converter.

gar

Senior Member
220920-2233 edt

It is simply a result of v = K*N* dPhi/dt.

How does a typical automotive ignition system work? I would think that electricians would be taught some of these basics.

.

tortuga

Code Historian
I would think that electricians would be taught some of these basics.
Sorry were not, and if we were we forgot care to give us a refresher ?

gar

Senior Member
220920-2354 EDT

I should also point out that a simple transformer without inductive kick is a useful way to increase voltage.

.

zbang

Senior Member
How does a Fluke meter work when measuring insulation resistance? Does it apply a certain test voltage and measure the return current to calculate the resultant resistance value? Looking through the Fluke 1587 specs, I see that "output" voltage on the meter is up to 1000Volts. How can that be? The Fluke meter uses (4) AA type batteries - how can it generate such a high voltage? Would 1000V be the maximum voltage that the meter is designed to measure?
Quite well.
Yes.
A voltage multiplier.
The same voltage multiplier.
Probably, but an insulation tester isn't measuring voltage, it's measuring current (question #2).

Fluke probably has a white paper or something that explains things.

Frank DuVal

Senior Member
Um, a transformer is not taught? Convert the DC to AC with a switching circuit (like points in old cars did), feed the primary of a step up transformer, use high voltage coming out of secondary. Lesson over.

tortuga

Code Historian
220920-2233 edt

It is simply a result of v = K*N* dPhi/dt.

How does a typical automotive ignition system work? I would think that electricians would be taught some of these basics.

.

garbo

Senior Member
Hi Guys,
How does a Fluke meter work when measuring insulation resistance? Does it apply a certain test voltage and measure the return current to calculate the resultant resistance value? Looking through the Fluke 1587 specs, I see that "output" voltage on the meter is up to 1000Volts. How can that be? The Fluke meter uses (4) AA type batteries - how can it generate such a high voltage? Would 1000V be the maximum voltage that the meter is designed to measure?
Thank you for your feedback.
Before I retired I used a Fluke 1587 combination VOM/ Megger dozens of times a week performing PM'S on over 500 drives & starters. Not sure how they produce the several test voltage ranges ( 250,500,1,000 Volts DC ) . Great Megger. Our shop had a few Greenlee Meggers that I never liked. I own a 40 year old Simpson Megger that supplies up to 5,000 Volts DC from 4 or maybe 6 D batteries. Found a grounded 4,160 motor with it. The Fluke 1587 is expensive ( think now over \$850 ) but rather only carry 1 meter rather then a separate Megger & VOM especially up ladders & roofs. Wish I had a dollar every time it got knocked off a 6' step.ladder. Only negative thing is if the 1,000 volt fuse blows you get a crazy Megger reading It's been 4 years since I retired so having trouble remembering exactly what the reading was.Not sure what the maximum voltage reading is but have measured the 650 to 675 Volts DC Buss voltage on 480 Volt drives thousands of time. We had several AHCU units with two separate enclosures with 100 & 125 HP and a 75HP return fan. If the return fan shut down it would run in reverse at a fairly good speed causing the DC Buss voltage to be over 720 Volts DC. Measured that several times with this best in class meter.

ptonsparky

Senior Member
Those meters have a good ohms range as well. A customer had a 100 HP motor causing the VFD to fault (IDR the code). Not a ground fault. We found a shorted winding.

I also like that they give the breakdown voltage of a fault.