On Tue, Feb 12, 2013 at 10:57 AM, Dave <[email protected]> wrote: > I have a large CNC lathe that has contactors wired in between the servo > drives and the motors and on an Estop, the contactors drop out and the 3 > phase servo motor windings are shorted together to stop the motors.
I thought this is a no-no---opening of the circuit causes the servo driver stage to abruptly change from high-current to zero current flow, bound to cause transients in every inductance in the system. THere's a standard warning for the people rewiring their equipment with VFDs to take the reversing drum switch out from next to the motor, and replace it with something that commands the VFD to reverse. Is it one of those things that shouldn't be done routinely but is OK in an emergency? ------------------------------------------------------------------------------ Free Next-Gen Firewall Hardware Offer Buy your Sophos next-gen firewall before the end March 2013 and get the hardware for free! Learn more. http://p.sf.net/sfu/sophos-d2d-feb _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
