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Why is the AKD drive and all its variants not recommended to run DC servo motors? It does very well...

On past occasions we have had special cases where we HAD to use an AC servo drive to run a DC servo motor;  Heck, we have one now where someone is rebuilding a very sophisticated many axis telescope that once resided at the South Pole.  It will require new KBM Ac direct drive motors on some axes, othhers have good TT2922 style DC motors they will not replace.  But we need to run all axes with the same AKD drives.  So,  as in the past, we experimented.  And, as in the past, we found the AKD a very formidable DC servo motor drive!

Simple key is to

  1. define FB1 as resolver, set transformation ratio = 2, then tie ref hi to sin&cos hi, ref lo to sin&cos lo to satisfy the current loop.
  2. Use encoder feedback into FB2, set velocity loop (and position loop if used) SOURCE to FB2.
  3. Run the drive in torque mode.

Works very well.   If Kollmorgen will agree to 'sponsor' this approach, I am sure they would want to offer some comments on current limits, etc., to make it even  more robust. 


Comments's picture

Thanks for sharing this information