Does the speed need need to vary when it is running?
If so, you will need an invertor drive
If not, I i would use an auto-synchronous induction motor
This is basically a wound rotor induction motor with slip rings. It starts as a wound rotor, and the Back EMF is limited by banks of resistors connected to the rotor windings connected through the slip rings
As the speed builds up, the resistors are taken out by banks of contactors in sequence
when it is up to slip speed, the final resistors are taken out and DC is applied to the rotor to make it synchronous. They are very high power (and torque) and sound ideal for your theoretical application
They have the added advantage that when syncronous, you can over-excite the rotor and turn it into a synchronous capacitor, which, if you are using it in a large industrial application, can be used for power factor correction
they are identified by the fact that one slip ring is larger than the other two, because when DC is fed to the rotor in synchronous mode, power goes in on one slip ring, and back out on two, so when is larger to handle the current flow
perhaps this has helped, perhaps it hasnt, but hey, its Bank Holiday Sunday and i'm on the 'Bow!!!!
