2012/6/13 Todd Zuercher <to...@pgrahamdunn.com>: > > I was thinking of picking up some AMC servo drives off ebay (BE12A6 > drives seem to be cheep and plentiful there).
Mesa 8i20 is cheaper, do not know about Pico drives. And paired with KL34BLS-98 ($134/pcs) servo motor it should be a good match: motor has peak current of 33A (and more than 4Nm torque there): http://kelinginc.net/34BLMotor.pdf The drive will handle up to 30A. What do others think of this combination? I was thinking about using them this way. Unfortunately it requires relatively larger power supply with higher current output. OTOH I suspect that commanded acceleration limits will have impact on how much torque is drawn from motor and thus how much current will it need. But that is just my own speculation... > What would be a good motor for this and where to buy them? (Max RPM > will be less than 1500 without changing gearing, with 1000 being more > realistic.) I think that with servos You can easily expect much higher RPM. That Keling, for example, is rated for 3000 RPM. > How high of a resolution encoder will I need? I think that generally it would be - the more resolution, the easier tuning and better positional accuracy. The card that counts those pulses is the limiting factor. If the motor can do 3000 RPM = 50 rps, then 1024 cpr encoder will give 4096 ppr = 204800 pps. That is not even close to those few MHz counting rates I have seen for FPGA cards. > Short of cobbling together all this stuff for a closed loop system, I am > also considering buying a 4 axis servo system from DMM-Tech (costs about > $1700) and running Linuxcnc open loop. (probably still use the 5i25 for > hardware step generation). And for LinuxCNC You still would have the same open-loop step-dir system... IMHO doing it that way loses at least 75% of the reason, why would one better use servos instead of steppers. 1700$? 4 Keling motors would be 536 $, 4 8i20s would be 960 $ = 1496 $ total... Add the cost of wiring and it would be somewhere there. The whole difference is in the degree of control You have. -- Viesturs If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
