Re: Quick & Dirty Current Shunt


"ehsjr" <ehsjr@xxxxxxxxxxxxxxxxx> wrote in message
news:70Zzl.541$Q52.302@xxxxxxxxxxxxxxxxxxxxxxx
Tim Wescott wrote:
Problem: I need to measure up to 30 amps (50 would be nice), I've spent
my discretionary budget for the upcoming month, and all I have are 10A
meters.

What's a good quick & dirty current shunt? There's no dead heaters on
site -- would it make sense to hack a bit of FR-4 to just the right
length & width to develop 50mV at 50A (while dissipating 2.5W, of
course)? Or should I find the right length of copper wire to do this?


The right length of copper wire works only briefly,
depending on the accuracy you need. It heats up and
calibration changes until it cools again. Spreading
the copper out using a pcb might help to cool things
more & get less variation due to heat. Maybe copper
gutter flashing? (more airflow, less delta T & delta R)

Ed

I like the 3 meters in paralell. or the three meter shunts in paralell.

Bob


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