nwboson
Member
VFDs are notorious for injecting noise since they use 'chopper' transistors to switch an inductive load (the motor), you have significant L* di/dt which means potential for lots of voltage spike. If you temporarily disconnect the VFD grounds, does the problem go away?
I normally build my panels with 3 separate GNDs: analog ground, digital ground and VFD ground. They are completely separate buses, except each one has one and only one wire connecting the respective ground bus to earth. This prevents any current flow between grounds but places each ground at earth potential.
I normally build my panels with 3 separate GNDs: analog ground, digital ground and VFD ground. They are completely separate buses, except each one has one and only one wire connecting the respective ground bus to earth. This prevents any current flow between grounds but places each ground at earth potential.