Fehlmann Picomax 50 CNC conversion/refurb

[Agathon]

Mach3 generates a 12.5Kc/s pulse onto one of the pins of the PP This is used to enable the bob. When Mach3 starts up. It is used in case there is a software problem or e stop situation the pulse disappears and basically switches the bob off.

Re the drives is is usual for us to have a two to one reduction with a belt drive. I use these AM882 on my mill.
Your mill though is in a league of its own.

I'll do some research on charge pumps.

I have been puzzling about using Nema 23s with a reduction drive, but can't see how this will help in my situation. If I wanted to achieve 1000 rpm at the feedscrew the motors would have to run at twice that speed with the inevitable massive drop-off in torque. Even if the torque itself is multiplied by 2:1 (which it won't due to losses in the drive belts etc) the torque of the motor is likely to have dropped way below any mechanical gain. I can see how it helps with gaining torque at lower speeds, but looking at the torque curves of even the lowest induction and rotor inertia steppers it looks like less than a zero-sum game to me since their torque drops down to less than a third of their maximum. By the time any motor gets to having nearly 7000 steps a second they're going to have no torque at all. These topsy-turvy stepper things do my head in!