I have a mid-80s Italian 28 inch Centauro Bandsaw which runs fine and has been forever. It has what looks like the "factory" power cord - a twelve foot long 12/4 SJO. The saw is powered by a 3-phase 5.5hp 16.2 amp motor (Motori Bonoro Cento).
This brings up a more fundamental question related to an overall redesign of the circuit for this machine. It is currently on (plugged into) what is effectively a 35 amp circuit (40 amp breaker and 35 amp time delay fuses) since it is powered by an RPC which is powering numerous 3-phase machines in the shop. The saw has never tripped that breaker or blown the fuses. Testing load is a bit problematic, with the fuse/breaker ahead of the RPC, I'm not sure which I'm actually testing if I reduced the size of the initial breaker. Clearly, a 12/4 cord is not rated for 35 amps, but that's not the question here. I'm looking to add a 3-phase load center between the RPC and tools which would provide a solution to that problem. What size breaker is this machine going to require to run? I know that selection of that breaker is going to have some impact on the THHN I was going to run for that circuit. For instance #12 is "rated" at 25 amps, but limited to a breaker no larger than 20 amps (per NEC 310-16). Theoretically, the 12/4 cord is sized just fine for a 20 amp circuit, I'm just not sure the machine will start on that, and I don't have a good way (I'm not experienced in this - see above issue with testing circuit) to test before installing the load center. Also, does the cord of that gauge have any impact (voltage drop or resistance?) on the breaker sizing?
Looking for experienced views. Thanks!