What does the 'watt' specified for a motor mean?
International standards require the rated output mechanical power to be marked on a motor's rating plate. That would suggest that a motor with "1500 watts" marked on it should be capable of delivering 1500 watts of mechanical power to a load. However there is no guarantee that any particular motor conforms to international standards un less the literature or rating plate indicates that the motor conforms to IEC, NEMA or some other international standard. There may be also a marking on the motor that indicated whether or not it is rated for continuous duty. A 1500 watt motor rated for continuous duty should be capable of delivering 1500 watts of mechanical power 24 hours per day, 365 days per year.

A motor's frame size usually designates the physical dimensions, particularly the mounting and shaft dimensions. A given motor frame size can accommodate a range of speed, and power ratings. The torque rating for a given frame size may vary, but over a smaller range than the speed and power ratings.