Hello Warren,
that should be possible, I have used a A1302 Hall sensor as a "no contact" >100A current monitor.
The sensor was just some mm away from the wire and was calibrated once using a (expensive) amp. meter.
At lower currents it might be better to let the wire run a small loop with the sensor inside.
The output voltage is proportional to the magnetic field (= current through wire) with a offset voltage of 2.5V (at 5V supply voltage).
Just be sure to get a linear Hall sensor (not the latch type) and be aware that most Hall sensors are rather slow (some 10..100us response time). So
at 136kHz it will resond to the average current rather than peak currents.
73, Rik ON7YD - OR7T
Van: owner-rsgb_lf_group@blacksheep.org [owner-rsgb_lf_group@blacksheep.org] namens Warren Ziegler [wd2xgj@gmail.com]
Verzonden: maandag 8 april 2013 21:07
To: rsgb_lf_group
Onderwerp: Re: LF: Re: Hall Effect for Over-current shutdown?
Hi Alan,
I've modified the G0MRF amp with the M0BMU output configuration, I'm using a 30V supply.
The G0MRF uses a current sense resistor to shut down the amp quickly in case too much current is being draw.
I've modified the output transformer turns ratio to produce more power at lower supply voltages (I'm using 500V, 55a FETs).
However with the new higher currents and with a new appropriate value sense resistor its developing a LOT of heat (12 W or so) and needs to be heat-sinked.
I'm thinking Hall-effect might be more efficient and produce less heat - I'm pretty sure that others have used Hall effect devices to protect MOSFET amplifier and I'm looking for circuit tips.
73 & Tnx!
Warren
