The best time to handle electrical noise problems is before they occur. When a system is in the design process, the designer should consider the following set of guidelines for system wiring:
Put surge suppression components on all electrical coils: Resistor/capacitor filters, MOVs, Zener and clamping diodes.
Shield all remote connections, use twisted pairs. Shields should be tied to Earth at one end.
Put all microelectronic components in an enclosure. Keep noisy devices outside. Watch internal temperature.
Ground signal common wiring at one point. Float this ground from Earth if possible.
Tie all mechanical grounds to Earth at one point. Run chassis and motor grounds to the frame, and the frame to Earth.
Isolate remote signals. Solid state relays or opto isolators are recommended.
Filter the power line. Use common RF filters, and use an isolation transformer for worst case.
Filter the lines between the drive output and the motor.
A noise problem must be identified before it can be solved. The obvious way to approach a problem situation is to eliminate potential noise sources until the symptoms disappear, as in the case of ground loops.