Comment on Why do we still use stepper motors?
KingRandomGuy@lemmy.world 5 months agoBLDC and AC servos maintain full torque at stop too, and have about 2-3× the torque of a stepper of similar size.
Huh, this is true about BLDCs as well? I remember seeing in a video that BLDCs tend to have very poor torque output when stopped and especially when at low speeds, whereas AC motors have a pretty much flat torque curve until they get fairly fast. I’d be interested to know if this is true.
Eranziel@lemmy.world 5 months ago
That sounds like a problem from using too small of a drive. Every torque curve I’ve seen for brushless DC or AC servos is constant torque from 0 to about 75% rated RPM, and then starts to drop off.
KingRandomGuy@lemmy.world 5 months ago
That sounds about right. You can technically achieve full torque at 0 RPM, but the current required for that might be very high (and may not be practical for the small size, power limits, and cost of a 3D printer). I know this is a probably in Asian import mini-lathes - if you run the spindle too slow you won’t get much torque out because the driver can’t supply enough current.