I have a client who wishes to use a 200 amp 3 phase 50 hp motor and associated equipment. It comes out at 208 amps of capacity and so I would normally put in a 75 kva transformer to kick his 208V up to ~480. No problems so far. However, he anticipates putting in a second 50 hp motor and he has a 150 kva transformer already and he wishes to avoid buying a 75 kva if he doesn't have to.
Can we size everything to the 150 KVA, put in 200 amp fuses for now (resize them when he adds the new 50 hp motor) and call it a day? I don't have a good explanation as to why a 150 kva will not *work* but I would like to be able to tell him exactly why it would or would not be a bad idea. Safety wise, I think he is fine. Everything is properly sized to handle the load. I worry though about power factor and other associated losses.
Any thoughts?
Can we size everything to the 150 KVA, put in 200 amp fuses for now (resize them when he adds the new 50 hp motor) and call it a day? I don't have a good explanation as to why a 150 kva will not *work* but I would like to be able to tell him exactly why it would or would not be a bad idea. Safety wise, I think he is fine. Everything is properly sized to handle the load. I worry though about power factor and other associated losses.
Any thoughts?