The x and Y motors I'm using to run my CNC are chopper motors, I believe. They came out of a set up where they were each driven by an stk675-050, and possibly driven with 24v. There isn't a voltage marking, only a 0.8, and a 1.8deg. The rest are numbers that I haven't quite found the answer for. The 0.8 is the impedance, which I have verified, and the 1.8deg is the degree per step. The "TYPE" is "23KM-K224-P2", the "No" is "T 202-01", and the "DWG NO" is "AXC501S7C", all by Minebea Co., LTD, and made in Thailand. All three of the motors very slightly from one another, but eh impedance and step are the same.
Since their impedance is only 0.8 ohms, which at 5 volts is 6.25 amps. So when the motor is just sitting in one place long enough, two coils are going to dissipate a constant 31.25 watts. This is apparently enough to get them pretty hot after just running through the first example that loads in LinuxCNC.
So the main question is, will the pwm from the arduino be a good frequency that won't bother operation at say 50%-75% pulse width? Instead of running on pins 2, 3, 4, 5, use pwm pins 5, 6, 9, and 10, and set the library to analogWrite instead of digitalWrite. Or should I look into a lower supply voltage for these motors?