[bshapiro]

Hi all,

I'm an infrequent visitor, but recently was looking for info about closed-loop 3-phase steppers vs. brushless servos. I'm trying to find the least noisy strategy for producing 2 and 3-axis custom rigs (motion control sculptures). I switched from open-loop steppers to servos a while back, but am curious if closing the loop (and adding a phase) might be "better," if what I want most is quiet?

Bruce

[Al_The_Man]

I only use servo's, either DC brushed or BLDC, and it is hard to detect any sound unless they are wound up, and then it is usually mechanical noise separate to the motor.
Al.

[bshapiro]

Thanks for the response, Al! But the real question is about the whole system-- from motor to load. My servos probably aren't the cause of the noise I hear, it's the gearheads (both planetary and harmonic make more noise the faster they go). If I could use closed-loop steppers at lower RPM, might they be quieter than the smaller servo in combo with a fast moving gearhead?

[datac]

H'mm interesting topic. I assume because you posted in the HobbyCNC section that you came from hobbycnc stepper drivers ? I guess I ask because I myself have used a few hobbycnc stepper drive kits and frankly, they have quite a bit of chopper noise especially when idle. The newer ones I put together have less, but noise nonetheless. I can ignore the noise in my environment on those machines that use them and those drivers have been ROCK RELIABLE. So, no complaints.

Now over the years, I have used other drivers.... Anahiems, IMS, Gecko's, blah, blah, blah, etc. All of them produced predictable "noise" in steppers when running, not much noise when not moving. However, I did recently replace 3 gecko's on one machine with whatever Flashcut uses in their ProDriver cabinet. Its SHOCKING how quiet this machine is now. I simply can not believe how much of a difference it has made in motor noise at all times. They are incredible !

All that said though, Servos are probably going to be the quietest, provided you have noiseless methods of mechanics connected to them (rubber spiders when connected to screws - belt drives, etc.) I would assume that you might find differences in drives... some quieter than others just like the stepper world.

[jm82792]

I agree as I just saw a RouterMate in person that uses Flashcut's software and I'm presuming hardware.
The thing was very quite.