Which servo drive can handle AC motor without Hall feedback?

[scsi]

So far I know of Granite, Tolomatic and Compax3. Tolomatic works but the software is very limited and buggy. Parker Compax cannot figure out commutation properly. Granite Devices is a big unknown and I will probably go ahead and order one to try it out.

Basically, I'm looking for an AC servo drive with dependable automatic commutation technology that is based only on encoder feedback. The encoder is very fast and the motors are linear, but that's another story. Ideally, the drive should take 240VAC power and accept analog 1Vpp encoder signal, but it's not necessary. Need to handle 3-5 amps continuously and 10A in peaks.

Thanks in advance guys!

[Matt Adams]

The Kollmorgen S300 drives can handle this sort of application. They use what's known as 'Wake n Shake' technology that pings the motors with short bursts of current, and then based on the movement, calculates a commutation angle.

I've used them multiple times in encoder-only applications, as well as linear motor applications. They take quadrature or sine-encoder feedback. They're available in 3 Amp continuous / 9 amp peak at 240 VAC.

I can help you size and select one if you provide the right information to me. PM me with the details.

Matt

[scsi]

Thanks Matt!

This is the kind of information I'm looking for. The 'wake n shake' technology in Kollmorgen servostar drives sounds exactly like the one that is used by Tolomatic. It shakes the whole machine for one second upon start up and figures out commutation phasing based on the encoder feedback.

I forgot to mention that my garage project is on a very tight budget and I'm shopping on ebay for most of the parts. Servostar S300 looks great and should do what I want but it hasn't make it to ebay just yet. The older Servostar CD looks promising though. Guess I need to try it if I find a model with encoder feedback.

Forgot to mention that I'm looking for the drive with positioning loop that can work off of step/direction motion controller (DeskCNC, don't ask why). Servostars seem to be able to do it. What else is out there?

[scsi]

Found another well known drives that do wake&shake - Ultra3000 from Allen Bradley. Apparently they have so called "self-sensing startup" option for motors without Hall sensors. Abundant on eBay at very affordable price. Will be trying these and Kollmorgen CD series drive with my linear motors next week. Should be fun!

-scsi

[Xerxes]

Granite VSD drives had a "wake and shake" feature in very early development days. I didn't like it so I developed a more sophisticated way to align phases without hall sensors. Basically I got rid of the "shake" part, so machine only moves gently when aligning phases.