fluke 1653 vs kyritsu 4118

2913 Views 8 Replies 6 Participants Last post by murdock, May 25, 2008

murdock

Discussion Starter · Apr 3, 2008

i have both these instrument...but i have found on numerous occassions the readings are totally different...is there a way of testing the instrument to see which reading is the correct one...

for example i was doing a loop impedance test on a 400 volt 3 phase system... using a 1653 connected to the earth neutral and red phase reading indicated 0.08 ohms did the same but on the yellow reading indic ated 0.12 ohms then i connected to the blue phase but the instrument indicated more than 2000 ohms did it 3 times the same reading...so i took out the 4118 and carried out the same test the instrument indicated 0.1 for all three phases...i dont get it.

i also did a similar test on a different installation the 1653 indicated there was a high loop impedance reading yet when i connected the 4118 it indicated the result within the spec....what i found interesting is the fact that the 1653 gives these kind of reading whenever i am testing an old lead cable but if i carry out tests on new cables it works fine...anyone have any ideas?

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Mountain Electrician

· #2 · Apr 3, 2008

I don't, but I'm sure Brian will. :thumbsup:

I have zero experience with loop impedance testing, although it looks to me like a valuable troubleshooting tool. From what I can get from Google, it looks like loop impedance testing is mostly a European thing, I certainty have never run across it anywhere I have worked. I would love to learn more about it, and maybe someone could recommend a tester we can buy here in the US.

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cornishsparks

· #3 · Apr 3, 2008

I once had the samr problem with my fluke 1651,check the lear connections if they are loose you will get error 5 or a high loop reading

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murdock

Discussion Starter · #4 · Apr 4, 2008

i checked and re tested 5 times to make sure...i get the same reading
connected earth to earth terminal
neutral to neutral bar
results:

red phase =0.08
yellow phase = 0.12
blue phase =<2000 ohms or error 5

what i dont understand is why the only the blue phase gives this reading each time i test....when i use the 4118 the readings are the same across all three phases.

i have similar problems when testing old lead cables...but the testin i am doing now is on new cables...the voltage readings are correct...when the power is on.

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murdock

Discussion Starter · #5 · Apr 4, 2008

has anyone else ever compared the readings of different loop impedance testers...and is there a way of checking the results are correct.

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tommy

· #6 · Apr 16, 2008

Fluke 1653

hello Murdock
the point is that the Measurement Range Operaiting Error is: Z- 2Ω-1000Ω +(15%+2dgt).

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randomkiller

· #7 · Apr 16, 2008

murdock said:
has anyone else ever compared the readings of different loop impedance testers...and is there a way of checking the results are correct.

I have even used three of the same Flukes and had all of them read differently. Not to the point where they are way out of wack with each other, I would say closer to the +/- 10% range. Our shops sends the meters out to be calibrated annually, when they remember.

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HighWirey

· #8 · Apr 17, 2008

murdock said:
i have both these instrument...but i have found on numerous occassions the readings are totally different...is there a way of testing the instrument to see which reading is the correct one... anyone have any ideas?

Regardless of whay you are testing, even with both of your test instruments calibrated by the same lab at the same time, and reading the same unknown, there will always be that plus or minus instrument deviation. And sometimes that combined deviation will gang up on you, yielding a way-out-of tolerence disparity.

The best solution is to use only one test instrument per test, provided that you have confidence in its veracity.

If you are under a Quality Control evironment, never allow an inspector to coerce you into breaking out a second test device for the same test :no:

Quoting RK "I have even used three of the same Flukes and had all of them read differently. Not to the point where they are way out of wack with each other, I would say closer to the +/- 10% range. Our shops sends the meters out to be calibrated annually, when they remember"

Best Wishes Everyone

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murdock

Discussion Starter · #9 · May 25, 2008

siily question...maybe you need to discharge the circuit or ground the circuit to make sure the circuit is not charged.

i rewired a bus rank and while doing insulation tests...found we were getting wacked if you did not dischrge the circuit becfore working on it.

maybe you need to discharge the circuit after you have tested it.

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