This is a follow up question to my question here about torque and stepper motors.
There Olin explains:
Note also that torque isn't the only criterion for a motor. Power is another important one. For that you have to decide what's the fastest speed you want to be able to pull the mass upwards at. Let's say 2 m/s for sake of example. From above, we know the highest upwards force is 5.8 N.
(5.8 N)(2 m/s) = 11.6 Nm/s = 11.6 W
After accounting for some losses due to friction and leaving a little margin, the motor should be rated for about 15 W minimum.
I'm unclear about what kind of Watts we're talking about here, is this just Watts in the mechanical sense or in the electrical sense. In other words should I be thinking about needing to deliver 15W as in 15V @ 1A?
I'm also wondering about controlling the amount of power delivered to the motor. In steady state I guess it would be Input Voltage divided by motor coil resistance? But to change the position where the current and voltage are changing the current must be the input voltage / (reactance of the coil plus the coil resistance). But the reactance changes with frequency... so do I have to look at the rise time of the input voltage to understand the frequency involved and then try to calculate from there.
I'm a little lost on that point, but trying to read more and understand.