[phomann]

Hi,
for decades prior to closed loop steppers being available open loop steppers were used to complete satisfaction. The only time an open loop stepper misses steps is if its overloaded,
thus if you correctly specify the open loop stepper for a particular application then it will never miss steps. Where then is he advantage of closed loop?

All steppers lose torque the faster they go, closed loop or open loop makes no difference. The manufacturers of closed loop steppers say 'goes faster, more power, never misses steps'.....all BS.
It is true that if a closed loop stepper being marginally overloaded and it misses a step, the drive will insert an extra step to catch up......but guess what, that extra step is just as likely to be missed as the regular step
Closed loop steppers can interpolate between steps in a manner that open loop steppers cannot, and so have more resolution, and can of course fault out m if it misses steps which it cannot recover rather than continuing making a misshapen part,
so they do have advantages.....but not enough to justify the cost.

I would suggest buying top quality, LOW INDUCTANCE open loop steppers with at least 80VDC drivers and not concern yourself with closed loop.

Closed loop is more marketing hype than truth.

If you really want 'closed loop goodness' then get AC servos. AC servos eat any stepper ever made....just a shame they are as expensive as they are. I use 750W Delta B2 series servos
and they are superb, and have such a generous overload ability you'd swear they were 3hp....not 1hp!

Craig

Saved me a whole lot of typing.
Couldn’t agree more.

Cheers

Peter.