Originally Posted by
109jb
The theoretical max current of a microstepping drive is 141% of the current setting. For example a 3 amp per phase current setting would mean the drive would draw a max of 4.23 amps.
At full step setting it is exactly what the current is set for. This is because at full step one coil is on and the other is off. When in-between full steps each coil is partially energized and it follows a sine-cosine type curve. At exactly 1/2 step each coil gets 70.7% of the full current setting, but there are 2 coils energized, so 70.7% x 2 = 141.4%
If the drive has the motor positioned at 1/2 step position and the drive is not set to reduce current at idle, then the idle current will also be 141% of the current setting.