DC Motor Ratings:

The nameplate ratings of a DC motor refer to the conditions of current, voltage, speed or power at that the motor is generally operated. The principal rating is known as the continuous rating, that is the rating described on the nameplate of a motor. A continuous power rating is a thermal rating.  At this power, the motor could be operated for long periods of time without a huge rise in temperature and beyond the limits of the conductor insulating material, bearings and other components that are greatly affected through temperature.

The speed rating of a DC motor is frequently given on the nameplate. This speed is the upper limit at that a motor could be operated without mechanical damage occurring.