Stairmaster

Good Q, dunno....
Better are their StepMills, which are like rotating staircases. Presumably all that varies in these is speed.
The best choice is the (free) staircase of a tall building. Infinitely more versatile, effective than these expensive contraptions -- $5K+..

There is no "Stairmaster"; which product are you referring?

There are only two. If you had a clue -- about anything -- you'd know.

Some of these are controlled for constant power. They have a small alternator with a resistive load. The controller monitors the load power (probably voltage into a known resistance) and varies the alternator field. I can feel the decrease in torque as I increase my cadence (speed) on a cycle. Hence my conclusion that these are constant power.
Some step machines prompt for the users weight and a speed setting. With these, it is possible to increase one's cadence above the setting and walk off the top of the machine. These might be constant torque systems, controlling the field based on power and RPM.
Some of these (many stair machines) plug in and just drive the steps at a constant selected speed.

Again, there is no "Stairmaster"; which product are you referring? Which product are you referring?

Maybe one of these: Good Luck! Rich

Again, there is no "Stairmaster"; which product are you referring?
Which product are you referring?

C'mon, spit it out - what pendantry are you trying to hint at?
Chris.