Quote Originally Posted by Voicecoil View Post
Are you sure the 110V AC figure isn't a RMS value to start with? It's the normal was to quote an AC voltgae unless you specifically say "110V AC pk" - anyway it does say also 5.9A constant current, so the voltage is kind of irrelevant.
To be honest I wasn't entirely sure, but it felt right.

For the three NEMA 34 motors respectively I used the maximum voltages (32*sqrt(L)) of 42, 64 and 82Vdc. The specs from the same manufacturer declared Vdc for the NEMA 23 and Vac for the NEMA 34 speed-torque graphs. My logic was that the drivers for these motors can be attached directly to a 110Vac supply like in the US and thus would have a numerically lower DC equivalent.

If I use 110 as the value for the supply voltage in the equations I also get 1645, 750 and 552RPM respectively for the max speeds for these same motors. It takes the power for each upto 649, 605 and 506W respectively. These values just felt way too high.

The supply voltage is one of the factors that determines the time it takes to reach the 5.9A maximum current. A higher voltage fills the coil to 5.9A faster. For example on my motors I get a current rise-time of 0.198ms and a max 759RPM on a 68V supply but if I were to swap this to a 36V supply the rise time goes up to 0.373ms and I get a max theoretical RPM of 402.

I'd really like to know what effect chopping stepper drivers have on the maximum speed of a motor and how half/microstepping the motor might influence these values though!