What are the myths and legends surrounding line conditioners? How do they protect CNC gear?

I have been having very consistent problems with burning up servo motors on start-up. I have sent in my control console to the manufacturer, along with another toasted motor. Our warranty is up and this could get real expensive. One of the tech guys asked about our electricity and asked if we were getting Hz spikes, I really have no clue. I ran new sub panels and new wiring before installing this table (along with a three 8' ground rods) but still seem to have power supply problems causing spikes to the motors. Actually we don't know what is happening. I just want to reduce the opportunity of this problem recurring.

What is the proper way to make sure your output is protected and within spec. limits?

Help!

WSS