All motors that I've encountered do not require a neutral connection to function. The motor might be internally connected in 'wye' but is supplied with only the three phase conductors, no neutral conductor.
If the _load_ requires a neutral for whatever reason, then you must provide that neutral conductor. But I would be very surprised if a 'motor load' actually requires the neutral.
Article 250 is about grounding, and 250.24 is about bonding the grounded conductor; relevant for the service but not for supplying an individual load. In addition to the 3 phase conductors, your motor load will require and EGC.
-Jon