Kirk Wallace wrote: > On Sat, 2008-06-07 at 13:06 -0500, Jon Elson wrote: > ...snip > >>would put the PWM duty cycle at 50%, the worst case. What is >>your DC supply voltage? >> >>Jon > > > 53 VDC unregulated with 500 uF of filter caps. So far the motor has had > no load. If you need more information let me know. If you want, I could > also ship this setup to you. On the other hand, I was just being curious > and currently have no application that will use this configuration. > Well, I've also found a goof in the servo amps made since about Nov 2007. I changed power transistors, and should have re-tuned the deat time setting. Some units have feedback between the power transistors and the opto-isolators, and oscillate when the controller is sending small pulse widths. Some amps trip the fault sensing, others just run hot, whistle, or work fine. I just discovered this this weekend. It is a fairly simple fix, but requires taking the whole amp apart to put two caps on the back of the board.
Your last order of servo amps may be included in this batch. If the power transistors say "FB260" on them, they need the fix. If they say "31N20D" then they don't. Jon ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://sourceforge.net/services/buy/index.php _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
