Quote:
Originally Posted by MPaulHolmes
Depending on the motor, it may not be using 7 amps. Also, there would be very little resolution, since it's a LEM Hass 300-s. There are 128 ticks of the A/D for each 300 amps. So, around 2 amps per tick of the A/D. Figure +/-1 tick of resolution, and it can only resolve +/- 2 amps. My guess is that the motor is using less than 7 motor amps, and so the PWM just ramps to 100% trying to see 7 motor amps.
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Since it is low current and just for testing with a small motor. How about taking the LEM 300 off of the copper bar and running a wire from the copper bar, looping through the LEM several times (not sure how many) and then to the motor? Thereby increasing the magnetic field measured by the LEM. Effectively reducing the LEM to say a LEM 20 rather than an LEM 300.