3000A clamp table and amplifier update #2

RE: 3000A clamp table and amplifier update #2

three-phase — Tue, 16 Apr 2019 19:48:46 GMT

Many thanks Gene. I did go and check the frequency response of the CM55 myself and it did surprise me how low it was. The older style tongue clamps did have a low frequency response due to the limitations of the magnetic circuit and the introduction of Rogowski coils provided a much higher frequency capability.

The Fluke i2000 I have will go up to 20kHz, so it must be a design choice by Flir to reduce the frequency capability within the electronics.

Kind regards.

RE: 3000A clamp table and amplifier update #2

genebren — Mon, 15 Apr 2019 21:33:18 GMT

Donald,

Another great update. It does appear that the clamp is rolling off at higher frequencies. Looking at the specification for the clamp, the AC frequency range is listed as 45 - 500Hz, so 5KHz is out of range. I do remember that many of the clamps that I have worked with in the past did have rather narrow frequency ranges.

The impedance of your coil does make it look like the amplifier might have trouble driving it at higher frequencies.

Keep up the good work!

Gene

RE: 3000A clamp table and amplifier update #2

shabaz — Mon, 15 Apr 2019 21:30:41 GMT

Hi Donald,

This is a great project, a nice challenge. I was wondering, (these ideas may have flaws..): if the coil could be possible with copper blanks per turn (e.g. like these) with the centre punched out and disposed, and then a slit cut, and then bent into a coil to attach to the next one. I can't figure out how to bond each one though.. maybe lapped slightly and soldered. Then, maybe the diameter can be smaller, to reduce inductance, with the larger rim of the blanks dissipating heat. However perhaps it wouldn't help, if the design ends up being too long (since the copper blank method wouldn't have an inner coil like you have implemented with wire). Or maybe a paralleled-up op-amp method for passing even higher current, reducing the number of turns.