This guy builds and sells on ebay e.g. item#7540255036. This one should fit the bill, the continuous rating for the motors are 7.8A each. It is highly unlikely that you will be running all three or four motors instantanously at continuous rating.
The one listed is 800VA I would think 1kva would be max. you would need.
The nice thing about these toroids is that winding can be modified or even added simply.
A search of the forums should come up with many examples.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.