Reducing RF Interference

This application note is meant for those with applications requiring a reduction in RF noise from Gecko drives. There are three ways of doing this and they are arranged from the simplest to the most complex. The first one should suffice for most applications; if the level of noise is still unacceptable then move on to the other two.


Use a shielded 5-conductor cable for your motor to drive connection; 4 of the wires go to the motor leads while the 5th goes to the motor case. Return the motor case wire to the drive’s power supply ground connection. Ground the shield to your electronics control box at the control box end only, leaving it disconnected at the drive end.


Install 20 to 50 uH chokes in series with each motor wire as close to the drive as is practical. The choke outputs go to the cable described above.


Install an L-C low pass filter (pi section) from your power supply to the drives. Make L 100uH; make C 1uF non-inductive (multi layer ceramic capacitor). Use this in addition to both of the above.

Categories: Application Notes Step Drives