Lars Segerlund wrote: > I have heard you guys speak highly of servos, and I haven't got a > clue if you are running DC or AC servo motors ? > > Most servo users in the low-cost/hobby world are using DC brush servo motors. But, there are some of us using brushless motors with either our own servo amps or commercial units. > The reason is that I have some AC servo motors around 100W or so, > would they be good candidates for a EMC machine ? > Better than steppers ? > At the 100 W level, the only advantage over a stepper is the position feedback. The motor performance is not much different. Perhaps a servo can offer less vibration, or run at high speeds all day without heating up. > I haven't considered them since the control is a bit complex, but I > believe that it's simple enough to give a shot if it's a big > performance boost. > I doubt there'd be much performance improvement on a small machine. The advantages of a servo are : 1. position feedback to the computer, so crashes and stalls can be detected. 2. greater speeds, and sustained speeds without overheating. Most steppers cannot run over 1500 RPM for long periods without excessive internal heating. 3. servos give full rated torque up to their maximum speed, steppers lose torque (very roughly) on a linear slope as speed increases. > Is that what quadratur control was refering to ? or was that only as > in driving/braking ? ( as in 4 quadrant converter ). > I think the mention of quadrature may be in reference to the output waveforms from the parallel port. Stepgen has a variety of schemes to command a motor drive other than step/direction. There is a quadrature output where the 2 outputs look exactly like an encoder signal. This can be easily converted to the signals to drive the 4 transistors of a unipolar driver or full-bridge bipolar driver.
Jon ------------------------------------------------------------------------------ Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing. http://p.sf.net/sfu/novell-sfdev2dev _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
