Amps maxed out.

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Steve Crayston
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Amps maxed out.

Post by Steve Crayston » Sat Mar 21, 2020 11:53 am

Hi All,
Just tried to do a RC current test & the Clamp is set for 2000 Amps.
The Current draw is more than 2000 Amps so goes off the screen.
Is there any way I could overcome this?

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PicoKev
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Re: Amps maxed out.

Post by PicoKev » Sat Mar 21, 2020 1:16 pm

Assuming the current in the circuit you are testing is likely to be more than 2000 Amps? (Circuit / System Knowledge! :idea: ) then probably the only way to get an accurate representation is to invest in a more suitable clamp for the expected peak current you intend to measure.

If you are not too bothered about accuracy then just measure the voltage being outputted by the clamp and do the conversion as per the clamp specs, as most clamps will measure a bit above their intended range but the accuracy is far from guaranteed!.

Kev.

Steve Crayston
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Joined: Tue Feb 11, 2020 10:31 am

Re: Amps maxed out.

Post by Steve Crayston » Sat Mar 21, 2020 8:18 pm

Thanks for the help again Kev,
When you say "measure the output voltage of the clamp" is it just a case of telling the scope I'm just using a probe to measure voltage?

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PicoKev
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Re: Amps maxed out.

Post by PicoKev » Sun Mar 22, 2020 12:53 pm

Steve,

In a word "YES"

The longer version..... :roll:

Currents clamps do not measure current and neither do Oscilloscopes.
An oscilloscope at it's most basic level is the bastard child of a clock and a volt meter that later in life had simultaneous unnatural relations with a roll of graph paper and a plotting pen at an orgy in some lab somewhere! :oops: :oops:

So when you use a current clamp the clamp measures the EMF that surrounds the conductor (The Cable) converts that into a DC voltage output that is measured by that HellSpawned thing we call an oscilloscope.

The voltage variation is plotted over time and that is what gives us a waveform.

I do not know what Amp clamp you are using but let us say it is a Pico TA167 if you look on the front you will see that it's equivalence ratio is 10mV per Amp on the 200 Amp scale and 1mV per Amp on the 2000 Amp scale.

So if you were to set the clamp on the 2000 Amp scale and set your scope to say a 5 Volt scale that would give you a potential (If the clamp can manage it?) of measuring up to 5,000 Amps.

As I said in the earlier post be careful as the clamp is only rated at 2000 Amps and having never had to exceed that rating I do not know how accurate it will be.

:arrow: :arrow: :arrow: And do not forget that the SAFETY ELF will tell you not to do :roll: :roll: :roll: it!!!

Kev.

Steve Crayston
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Posts: 9
Joined: Tue Feb 11, 2020 10:31 am

Re: Amps maxed out.

Post by Steve Crayston » Mon Mar 23, 2020 10:04 am

Thanks again Kev,
Very eloquently put :lol: :lol:
It is a TA167, I'll try it next time I get near that Machine again & let you know.
Regards
Steve

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