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dynamite comes...
Its compact construction makes it ideal for fitting into tight distribution boards and comfortably manages individual circuits from breakers or fuses. In fact, there is yet to be a switchboard where this clamp has not been able to fit!
And this is where this little beast really impressed me! Tracing intermittent shorts can, at the best of times, be a tricky issue. Fault currents cause most current clamps to saturate hiding the true extent of the problem and little chance of an accurate trace of the recovery. My standard practice is to use a large clamp to detect the fault currents (I use the Chauvin Arnoux C-173 switchable clamp) and a smaller one to record the normal running currents (such as the M1.U). The C-173 is a big brute and easily handles fault conditions.
The M1.U is tiny by comparison, yet it exhibited exactly the same curve during a fault condition (shown above at 2ms/div). The tiny phase shift (which remains uniform throughout the curve) is attributed to a delay inherent in the instrument as it "scans" each channel throughout the waveform capture. I think it would suffice to say that when presented with evidence like this, I quickly ordered a few more for the PQ bag!
© 16.04.04 |
MEASUREMENT TECHNIQUES:
Pictured is the Northern Design M1.U range. I have the 200A:2V version giving me 1V at 100A, nice for 32A ring circuits etc. (and available in various configurations from 1A to 200A). 