Just be careful with the 3 to 1 phase conversion, when you change the motors from STAR to DELTA they do drop about 25% power. This may not be an issue on a 2.5T Molnar if you are only hoisting 2Tonne max with Holdens. The other option is find a secondhand 3 phase motor of the next size up, and once derated in DELTA it will be the right size.