Selecting Steppers that are more powerful than you need? Pros and Cons

[disneytoy2]

So,

I'm working on this large scale project. Not having large steppers on hand, I ordered a Hybrid 12nm Nema34. Haven't run it yet. It will certainly rotate the base as desired. But what id a 3n.m nema 23 motor would have done the same thing? Other than using more power, or costing more, is there any disadvantage running a more powerful motor?

I'm guess not, but curious of others opinions.

I do believe a Nea 23 2-3 n.m with a worm gear would have done the job. Not a big deal the 12n.m Nema 34 cost $200, the Nema 23 would have been $125-150 for a hybrid + I'd need the worm gear.

Also, I've yet to select a worm reduction gear. I need probably a pretty high reduction at least 100:1. Any pitfalls running high gear reductions? The end rotary table would only ever go 360 degrees over several minutes. So, I was hoping to trade off some really good torque.
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Thanks:-0)

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[ger21]

Other than using more power, or costing more, is there any disadvantage running a more powerful motor?

They often do not run as smoothly, especially at slow speeds. And if you need higher speeds, a much smaller motor may actually have more torque at the higher speeds.
It very much depends on the application.

[Jim Dawson]

So,

I'm working on this large scale project. Not having large steppers on hand, I ordered a Hybrid 12nm Nema34. Haven't run it yet. It will certainly rotate the base as desired. But what id a 3n.m nema 23 motor would have done the same thing? Other than using more power, or costing more, is there any disadvantage running a more powerful motor?

I'm guess not, but curious of others opinions.

My general rule is that you can always turn down the power on a motor that's too large. I have done exactly that for the Z axis on my mill. If nothing else it's easier on the motor and drive. It's pretty hard to get more power out of an under size motor.

I do believe a Nea 23 2-3 n.m with a worm gear would have done the job. Not a big deal the 12n.m Nema 34 cost $200, the Nema 23 would have been $125-150 for a hybrid + I'd need the worm gear.

The NEMA 23/gearbox combo would have actually cost more than the NEMA 34 motor, and would have a larger footprint.

Also, I've yet to select a worm reduction gear. I need probably a pretty high reduction at least 100:1. Any pitfalls running high gear reductions? The end rotary table would only ever go 360 degrees over several minutes. So, I was hoping to trade off some really good torque.
\
Thanks:-0)

The only issue would be the backlash that must exist in all but the most expensive gearboxes. There are zero backlash gearboxes for a price. Standard power transmission gearboxes normally have quite a bit of backlash, but if you are only turning in one direction then that would not be a factor. But rotary positioning would not be practical. A rotary table for a machine tool normally has adjustable backlash and all of the larger ones (=>6 inch) have a 90:1 ratio. The one for my mill will adjust to 0 backlash, and I do run it that way intermittently. But in a continuous use application it would not live long in that condition.

Overall it depends on the application to be able to get the best bang for the buck. For some applications I might use a standard gearbox, others a belt drive, and still others maybe a gear drive setup, or even some combination of the above.