Quote Originally Posted by JAZZCNC View Post
Normally You won't have any trouble running everything off a single 13a circuit or socket even when spindle is under full load or even stalled pulling max amps.
If the spindle is stalled and drawing rated, or even higher, current from the VFD, that's actually requires very little power from the mains. One way to think of it is to recall that power is the product of torque and speed, so when the spindle is stalled the speed is zero so the mechanical power required to apply rated (or any) torque is also zero. From an electrical point of view, you still have to put current through the winding to get torque, but that current in this situation is only supplying the losses in the motor ... so the power, and thus current, drawn from the supply is low - I'd guess an amp or two at most.

Assuming you're operating within the motor's continuous ratings, you can only draw a rated power from the supply when the motor is driving a load (be that a tool or just accelerating itself), at around rated speed. This is obvious when you consider that the cooling power of the water cooling system is limited, so for the input power to the system to be much higher than the cooling power there has to be a significant mechanical power draw, otherwise the motor would be fried as the extra power has to go somewhere.