Calibration Clamp current Meter

[Help Stan]

ISO-TECH ICM36 AC/DC CURRENT CLAMP METER
FUNCTIONS:

HOLD SELECTOR SWITCH
AC -DC SWITCH
200A - 600A RANGE SELECTOR SWITCH
DCA ZERO ADJUST DIAL

This is just a basic Clamp Current Meter.
Inside edge mounted on the PCB are 5 adjustable pots.
Please advise/speculate the role of each of these pots in terms of
Calibration.
And how to identify which is which by testing.
1 pot is for the adjustment of the DCA zero position on the dial.
How are these meters calibrated by a calibration house ?

Any info / help mush appreciated.

Regards
Stan

 

[Robert Baer]

Help Stan wrote:

ISO-TECH ICM36 AC/DC CURRENT CLAMP METER
FUNCTIONS:

HOLD SELECTOR SWITCH
AC -DC SWITCH
200A - 600A RANGE SELECTOR SWITCH
DCA ZERO ADJUST DIAL

This is just a basic Clamp Current Meter.
Inside edge mounted on the PCB are 5 adjustable pots.
Please advise/speculate the role of each of these pots in terms of
Calibration.
And how to identify which is which by testing.
1 pot is for the adjustment of the DCA zero position on the dial.
How are these meters calibrated by a calibration house ?

Any info / help mush appreciated.

Regards
Stan

I am guessing that each of the 4 remaining pots are for each range (DC
200A, DC 600A, AC 200A and AC 600A).
One can wrap (say) 10 turns thru the clamp and thus use 1/10th of the
FS current for calibration, or use a bobbin with 1000 turns for
reasonable level drive from a standard.

 

[mike]

Robert Baer wrote:

Help Stan wrote:

ISO-TECH ICM36 AC/DC CURRENT CLAMP METER
FUNCTIONS:

HOLD SELECTOR SWITCH
AC -DC SWITCH
200A - 600A RANGE SELECTOR SWITCH
DCA ZERO ADJUST DIAL

This is just a basic Clamp Current Meter.
Inside edge mounted on the PCB are 5 adjustable pots.
Please advise/speculate the role of each of these pots in terms of
Calibration.
And how to identify which is which by testing.
1 pot is for the adjustment of the DCA zero position on the dial.
How are these meters calibrated by a calibration house ?

Any info / help mush appreciated.

Regards
Stan


I am guessing that each of the 4 remaining pots are for each range (DC
200A, DC 600A, AC 200A and AC 600A).
One can wrap (say) 10 turns thru the clamp and thus use 1/10th of the
FS current for calibration, or use a bobbin with 1000 turns for
reasonable level drive from a standard.

I've done the multi-turn thing in the past 'cause I didn't have any
option. But I worry about the accuracy. Is the coupling to one
wire thru exactly the same as when you have many turns wrapped around
the core? A straight wire thru the center should have uniform coupling.
Turns wrapped around a small part of the core should/might have
different effective coupling coefficient due to the losses in the core?

Thanks, mike

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