It depends how the building is wired. If there is Bus Duct everywhere, it might not be but a few feet of wire to get to the machine.
If it is a long wire run, there is merrit to the idea, provided it is fairly easy to segregate the control circuitry from the machine tool circuitry.
Transformers are not cheap either, and it has become much harder to find used ones as many were scrapped a few years ago when copper & aluminum prices were way up.