I'm familiar with the problems created by some variable frequency drive and think that it has to do with the internal switching frequencies and is particularly bad on pwm inverters. (Someone please correct me if I'm wrong.)

I'm not too familiar with the newer drives and wonder if anyone has experience with the effects of igbt and vector drives on motors and possibly the effect of having too long a cable run. I have always heard that 50' is the maximum recommended, but that is probably dated information.

Any ideas out there?

Thanks,

Just asking again

Yes they are just as bad or worse.
Have a case of 8 pcs hot grinders, cubicle was same for all so 2pcs had longer cable and major problems until composite ceramic bearings was installed. I can´t say the lenght btw. the good and the bad as it goes around but physical distance btw. last units may have been 15-20 meters and the whole house 100-120 m. Good Luck! Olov