By the way Guldberg, I'd be carefull about using the phases as seperate circuit supplies, in case you get a phase imbalance and a ripple on the line.
The last firm I worked for had this problem to such a degree that our section leader used to go to the power cable inlet supply board around midday, each day, and hand feel the temperature of the three input phase cables to see which one was taking the most current.
When one got too hot to handle, I kid thee not, we used to shift machinery from one phase to another to even out the supply.
Eventually we had a larger transformer/substation attached to the pole outside the 'shop which supplied the needs.
Ian.