Well according to your numbers, you have a 240V machine drawing 5 amps or 240 x 5 = 1200 Volt-Amps. If it is indeed seeing .75 kW then that means your power factor is a pretty low .625. If you are changing out the motor to a 110V motor then it will draw about twice the Amperage, 240/110 = 2.2 x 5 = 11 Amps. If the power factor us unchanged, then the wattage is 11 x 110 x .625 =.756kW. So all you need is a 240V primary, 120V secondary, single phase, 1.5 kVA transformer. Very common piece of equipment. Jefferson Transformer makes one rated at 2kVA which will work, it is Catalog number 411-0091-120. You can see the enclosure and the wiring diagram (#S240A) on their website under "Encapsulated Transformers".
