I am trying to sense if DC current increases in a wire when the load changes. I do not care about the value of the current, I only want to know if it increases (motor at idle vs motor running). I cannot modify the wiring of this motor, so I need to do it noninvasively. I purchased a few analog hall-effect chips, hoping that if the chip was against the wire it would detect the change in magnetic field, but perhaps I need to brush up on my physics! I am seeing no change whatsoever when measuring the output when the chip is taped to the wire. I tried multiple orientations of the chip, as I know they are sensitive to poles, still nothing. As a sanity check, I used an actual magnet, and the chip responds as I would expect. I am using these (from digikey): part number: Texas Instruments DRV5053VAQLPG TI Chip Can someone tell me if I am close here, or lead me in the right direction? Thanks in advance!
The cylindrical field around a wire is fairly weak, so Hall effect current sensors use a C-shaped core to reduce the reluctance and direct the flux so that you get a decent signal from a Hall sensor placed in the gap.
picture from here