Has anyone converted their PRT Alpha to use Clearpath motors?

[Chuck Keysor]

Hello Shopbotters. Has anyone upgraded their PRT alpha to use Clearpath motors? Several years ago, I started such a discussion with a Clearpath applications engineer (but then became the chairman of my church's board of trustees for 5 years and set my shopbot to the side. My term has expired, and now I want to update my Bot. (5 feet by 12 feet)

The Clearpath Engineer/Tom Tuller that I worked with has retired, and the new person I connected with doesn't have Tom's records. But Tom had recommended a direct mechanical replacement for my bot's original motors, IE same NEMA size (I think it is NEMA 34). So no adaptor plate was needed. And because he pointed out various problems and costs with gearboxes, his recommended Clearpath had enough torque that I would not need a gear box.

I also don't know if all the motors were the same or not... I think that had not been resolved to my understanding before I got tied up at church.

And of course, I could not find the motor Tom recommended in my files. So if anyone has experience on this front, please let me know. My email address is: chuck.keysor@sbcglobal.net

Thank you for your input as I want to bring my Bot back to life. Chuck

[ken_rychlik]

If you want to wire the new servo's to run on shopbot control software, you will have lots of head scratching to do.

If you want to change out the whole system and run on a newer controller, reach out to Gary Campbell on the Centroid Acorn Forum. He had developed a complete kit and may still offer them. Everyone will suggest gear reduction for better resolution. Servo's are most happy when they run fast, and you will be asking them to run very slow without gear reduction.

If you are stuck on no gear reduction, look more at stepper motors than servo's. Steppers do very well at low speed. They do offer hybrid stepper motors with encoders that send positional feedback to the drivers. In the event of lost steps, they will send a fault signal to the controller.

There are many shopbots now running on Centroid and perhaps some of those guys will chime in. I repair machines, but don't have a shopbot anymore.

[Chuck Keysor]

Hello Ken. Thank you very much for your informative and timely reply!

a) Concerning the use of the Shopbot Control software, I believe that I am in luck on that score. I never used the SB software for anything except performing basic gantry moves, (zeroing, move in X, Y or Z). Anything above that I used Aspire, and I will continue to rely upon Aspire. A couple of reliable people told me that because of my reliance upon Aspire, that changing to an Acorn controller will not present much of a change.

b) As to having someone such as Gary do the work, I had initially considered that route for a number of reasons. In part because I am now retired from my major volunteer work and retired from real work, the money is down, the time is up balance has changed. And with my work background, the electrical integration should be very straight forward, especially given all of the readily available wiring diagrams from Centroid, and their user forum. On the other end, I have no experience in motion control, and have never been a fan of control/machine level software.

c) Your comment on gear boxes makes total sense. This is a case where when the application engineer made his suggestion, I suspended all critical thinking, and simply thought, "Oh, he is the expert, gearboxes have backlash problems, motors don't......" I'll contact the sales engineer from Clearpath/teknic and ask him to downgrade my interest in that aspect of my objectives.

d) It is my understanding that Scott Worden has taken over the conversion business from Gary. A number of years ago, when I was thinking of the conversion, I did communicate with Scott some and he seemed to be very knowledgeable and friendly.

Thank you again, I really appreciate your feedback!!! Chuck