The engineer who designed the electrical system for a new facility we'really building had new grounding ring connected to near by building ground grid. Is there any code requirement for this? Can we just have that connected to a different grounding source such as a column? I do not see anything...
Hello all! We have a situation where a 200HP, 480v motor controlled by VFD needs to have it's max speed limited to 54Hz. This is a fan motor (variable HP and Torque), so as I understand, if speed is reduced to 90%, the HP is reduced to (90%*90%*90%) = 72.9%, and Torque to 81%. But this is what...
