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Here is an example:
HAAS Automation designs their CNC machines as a 3 phase delta, 3 power wires and 1 ECG wire. The newest machines have one main power DC supply that outputs 325 V DC. This supplies the main spindle motor and the servo drives. Fundamentally it is a 6 phase rectifier providing an output ripple frequency of 360 Hz.
Most other motor loads are 3 phase (coolant and chip conveyor).
All low voltage power stuff comes from a single phase control transformer supplied from a pair ot the 3 phase lines.
Noise filtering includes a connection to the EGC (machine chassis).
Thus, the machine can be used on either a delta or Y source. With larger capacitors in the DC power supply or reduced output power capability some of the machines can be used on single phase.
My thought on a system of this type where there are a number of machines running simultaneous is to have a 324 V battery bank for a number of the machines. This accomplishes two things. First, float thru minor power dips. Second, good recovery of regenerative energy instead of dumping it to resistors.
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