Has it ever worked from your converter? Please do not try a capacitor only phase converter on these machines ( rotary ones are ok) they are motor killers and you do not want to replcae that motor!
If it has been working ok, then the usual problem is , as stated above, is the motor overload sensors . There is a small lever or button to reset them on each one, any one tripped will stop all the contactors working, so reset all of them.
Check for blown fuses and loose wires on the contactor coils terminals .
Check the reverse switch , on some (uk) machines this disconects the main power when operated , so if it is in a half-way state it will stop the power contactor working.
You've checked the spindle lock (always catches me that one!)
Bill