Variable Frequency Drives

VFD's used in common busbar systems should have second environment filters so as to reduce the current harmonics in to the system. Using a lower pulse inverter (generally 6 pulse) will cause such problems. It is recommended to use a higher pulse PWM (12 or more).

We have similar problem in our industry with ABB drives ACS 800 without second environment filters. Solutions are available for these problems, but not economical. We are also looking for economic solutions.

You can do a engineering change, by shifting your non VFD feeders to another bus bar. (Simple and best mehtod) if possible.

i think the vfd in your case generates harmonics which will heat up the neutral wire and cause the elr to trip.........is ur vfd compatible wit yo motor (technical ratings?).......does yo vfd have emc filters inbuilt? is ur motor rating compatible wit the load driven by the motor?....vfds can be connected in a common bus, it jus depends on the load which s driven by the motor.....usually for small loads they can be connected to a common bus bar, i don know whether it s applicable for very large loads.......

Installing a 1 to 1 ratio transformer from line to VFD will eliminate some or most of the problems by serving as a choke to suppress most of the noise generated by the VFD.

Try it.It works .

HTRN