single phase to 3 phase

You got to have a 3 phase supply for a 3 phase machine which is the best way to do .

not necessary, sometimes a single phase to 3 phase converter has a lot of advantages.

Buy a frequency converter if the load of the motor is within 5 HP. These accept a single phase supply and deliver 3 phase output. You'll have a lot to play with: starting couple, delay, overload protection, brake, frequency. (from less than $200) Many suppliers: Stephan AG, Siemens,

some with digital displays.

Exactly what kind of "3 phase machine" are we talking about here?

If you optioned to have phase converter, you must consider its efficiency and power quality and voltage balance. Static phase converters are simple device with no moving parts, although they do not lost much power, the equipment being supplied should be derated to about 50% of its rated capacity because of unbalanced phase, perhaps only 2 windings of a 3 phse motor are being supplied by a 3 phase converter. Rotary phase converters supply balanced 3 phse voltages but difficult to control, also they have more losses in themselves, you can expect converters' capacity 2 to 3 times the load rated capacity. Oversize converters waste around 30% the power they draw. The poor PF also contributes to decrease in efficiency. You may try VFDs or Digital Phase Converters, they are solid state devices with a well balanced 3 phase voltages. They have above 95% efficiency.

A rotary phase converter (motor driving a generator) is the most energy efficient way to go. When energy is the most expensive thing you are going through, this may well be worth the expense.

Maybe solid state phase converters are better now though. I am okay with being corrected....technology is rocketing forward all the time.

I have been building phase converters for many years and have developed a solid design that allows a stock three phase motor to be run directly off of single phase source without the need for a VFD or rotary unit between it and the power source while still being capable of working with its full starting torque and running power as well.

Here is the link to how you build and set one up. http://www.electro-tech-online.com/re-projects/100563-3-phase-converter-schematic-miller-system.html

I have built countless numbers of them with working ranges from 1/2 hp up to 25 Hp at this point and all have worked well in their stock applications with out problems.