Looking for help in finding the 'best/quickest' fix. Added a vfd to a knee mill and when the spindle powers on getting a fairly steady interference signal into the z-axis encoder signal. The encoder wiring is shielded back to the replacement PC controller in a cabinet separate to the vfd. The vfd motor output lines do parallel the encoder wiring a good distance, but this was factory and worked OK on normal 3-phase line power and original controller, is now a problem with vfd and PC retrofit.

Should I try to get shielded motor cabling, and any good source (3hp spindle)? Or reroute new shielded encoder signal cable away from motor leads? What is the most common/typical problem with VFD and signal noise? I'm counting on some 'been there, done that' experience to fix the 'real' problem, cheapest, fastest, and effectively. Especially since sheilded power cables seem a little harder to find.