# Fluke 87v AND i410 - question about AC amp readings.



## TOOL_5150 (Aug 27, 2007)

I have an 87V and used my i410 AC clamp on circuit. [meter set to VAC, as stated in the manual] I was wondering if it is normal for the reading to take a few seconds to "average out" so to say. When i have it clamped around nothing - its reads .3 then I clamp it around a load and gradually [about 3-5 secs] goes up to the reading and pretty much stays there. Just wanted to make sure my test equipment is working properly.

Also, I noticed there is an Arrow on the amp clamp. Is that for DC readings? I dont remember seeing anything about it in the manual.

~Matt


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## MDShunk (Jan 7, 2007)

That arrow (or dot) goes in the direction of current flow. It does matter on AC, and I'm at a loss to explain why. I know that I put one on backwards for my power quality analyzer for a whole week one time and had to redo the readings.


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## 480sparky (Sep 20, 2007)

My i410 does not have any dot or arrow. Nor do the instructions say anything about it. All I see is three 'tic' marks for centering the conductor in the clamp.


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## wptski (Jun 30, 2008)

That doesn't sound right! How would you measure inrush current that may only last 100ms? Try another DMM or current clamp if you can.

I was using a 87V on a duty cycled 1Hz 12VDC automotive signal that was down to 10% which 10ms. This read the same on a scope too.

The current clamp direction makes a difference in PQ stuff because of the relationship beteen voltage and current, voltage leads current in a inductive circuit. If your clamp is wrong you'll get negative power factor or you'll have current leading voltage in a inductive circuit.


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## TOOL_5150 (Aug 27, 2007)

480sparky said:


> My i410 does not have any dot or arrow. Nor do the instructions say anything about it. All I see is three 'tic' marks for centering the conductor in the clamp.


So you cant just clamp on a conductor and let it hang?

~Matt


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## TOOL_5150 (Aug 27, 2007)

wptski said:


> That doesn't sound right! How would you measure inrush current that may only last 100ms? Try another DMM or current clamp if you can.
> 
> I was using a 87V on a duty cycled 1Hz 12VDC automotive signal that was down to 10% which 10ms. This read the same on a scope too.
> 
> The current clamp direction makes a difference in PQ stuff because of the relationship beteen voltage and current, voltage leads current in a inductive circuit. If your clamp is wrong you'll get negative power factor or you'll have current leading voltage in a inductive circuit.


Crud... I dont have another meter or amp clamp to verify anything with. The battery in the amp clamp read 9 volts so I wouldnt think it is that.

~Matt


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## wptski (Jun 30, 2008)

TOOL_5150 said:


> So you cant just clamp on a conductor and let it hang?
> 
> ~Matt


It doesn't matter if you just want to measuring AC current alone. It only matters in PQ testing where the phase angle between the current/voltage are measured and used to calculate other values.


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## wptski (Jun 30, 2008)

TOOL_5150 said:


> Crud... I dont have another meter or amp clamp to verify anything with. The battery in the amp clamp read 9 volts so I wouldnt think it is that.
> 
> ~Matt


If you use your 87V to measure a low AC source like N-G in a receptacle, does it react slowly too?


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## KayJay (Jan 20, 2008)

I know that my similar i1010 clamp will normally read 0.6A with no load. This is with my 87 meter in the 400 mV AC range. 
Even on my 337 and older 36 clamp meters, the tenths digit will almost never settle to zero after powering on. Sometimes it will after taking several current readings, but even so, I don’t believe that this has any bearing on accuracy of the actual readings with these types of current clamps. 

I’m not sure about any delay in display readings your seeing though, because I can use my i1010 with a line splitter to read inrush on things like bench grinders and compressor motors on the 87 comparable to what my 337 can do.
I always press the range button once right after turning the 87 on to manually lock the meter in the 400 mV AC range, even thought the meter starts in this range with Auto mode when you first power up. 
I’m sure it makes no difference at all, but this is my feeble attempt to prevent the meter from range hunting during inrush readings.

The arrow on top of the i410 and i1010 clamps is also present on my Fluke 36 and 337 clamp meters. There is no mention of it in any of the manuals, but I have always just assumed it was for orientation of the current clamp toward the load. Apparently not really critical for everyday general-purpose current readings.


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## TOOL_5150 (Aug 27, 2007)

wptski said:


> If you use your 87V to measure a low AC source like N-G in a receptacle, does it react slowly too?


That was what I was reading. I had a cord that allowed me to clamp onto the hot line and was measuring the amp draw of some computer equipment, which was under 5 amps.

~Matt


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## wptski (Jun 30, 2008)

TOOL_5150 said:


> That was what I was reading. I had a cord that allowed me to clamp onto the hot line and was measuring the amp draw of some computer equipment, which was under 5 amps.
> 
> ~Matt


I meant measure *voltage* from *N-G* where it should be less than 3VAC and maybe less than 1VAC. Trying to find some AC voltage that's very low to check how fast your 87V responds to eliminate it as the problem.


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## TOOL_5150 (Aug 27, 2007)

wptski said:


> I meant measure *voltage* from *N-G* where it should be less than 3VAC and maybe less than 1VAC. Trying to find some AC voltage that's very low to check how fast your 87V responds to eliminate it as the problem.


Oh sorry - I guess i didnt take in what i read. Ill giove it a try and report back

~Matt


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## wptski (Jun 30, 2008)

I have a Fluke i1010 which looks just like a i410 with a different range. The current flow direction arrow is etched right into the yellow part of the case between the jaws.

I clamped the i1010 on a load that was just over 6A using a 87V and it did take maybe two seconds to countup/stabilize at 6.2A.


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## TOOL_5150 (Aug 27, 2007)

I sent fluke this:
"I have an 87V and used my i410 AC clamp on circuit. [meter set to VAC,
as stated in the manual] I was wondering if it is normal for the reading
to take a few seconds to "average out" so to say. When i have it clamped
around nothing - its reads .3 then I clamp it around a load and
gradually [about 3-5 secs] goes up to the reading and pretty much stays
there. Just wanted to make sure my test equipment is working properly.

Also, I noticed there is an Arrow on the amp clamp. Is that for DC
readings? I dont remember seeing anything about it in the manual."


I got in responce this:
"Matt,
Unless the circuit you are measuring takes time to level, this isn't
normal. The i410 will respond as fast as your meter will."


What a crappy company. Thanks for the help you flukes! 

~Matt


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## 76nemo (Aug 13, 2008)

When you first enter into the amperage mode, it won't zero out, it will see a field effect which is nothing more than noise to the meter. However, it should NOT take 3-5 seconds to easy out. If you are already in the amperage setting after the initial "zeroing", a term normally used in DC measurement, something is not right. The Fluke rep was correct in stating the clamp will read/measure in correspondence with your meter. Are you absolutely sure the measurements you are taking are stable at the time? If so, I agree, something's wrong. Have you seen this problem all along with your clamp Matt???


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