Current Sensing - No loss - Hall maybe?

[kinarfi]

I have a circuit the can pull over 100 amps and I want to shut it down at 40 - 50 amps. I have the shut down method designed and working. What I need help with is sensing the current fairly accurately and adjustable with out an inline resistor. I like the Hall Effect, but I think, don't know, that the Gauss would have to be variable some how, distance or shunt, or does the Hall effect output vary with flux like a transistor out varies with base current.
Any one have any ideas?
Thanks
Kinarfi

 

[Sceadwian]

You would need a Hall Effect transistor, not one with a switch output. But calibration might be difficult, flexing in cabling movement of the sensor etc.. would produce variation.

 

[dougy83]

What I need help with is sensing the current fairly accurately and adjustable with out an inline resistor.

The wires going to your circuit are inline resistors. You can just measure the voltage drop across one of the supply lines, which can be amplified as required to give you a current reading.

 

[tcmtech]

Just use a pass though current sensing device or transducer. They work just like a current sensing transformer but with DC as well.
They produce an output voltage signal proportional to the current being sensed.

LEM is one manufacturer.

 

[MrAl]

Hi,


As others were saying they make Hall Effect Sensors now that sense current
through the package pins and produce a voltage output that is proportional
to current. They go up pretty high too now, 100 amps is doable.
The part number for one such sensor is ACS714, but there are others too
in that family.

 

[kinarfi]

Just use a pass though current sensing device or transducer. They work just like a current sensing transformer but with DC as well.
They produce an output voltage signal proportional to the current being sensed.

LEM is one manufacturer.

Thanks,excellent tip.
kinarfi