Stray load losses measured in D-C motors

STANDARD open general-purpose d-c motors, rated 0.5-, 5-, 10-, 25-, and 50-horsepower, 40 degrees centigrade, 1,750 rpm, have been tested for stray load losses by five manufacturers on an exchange program at the request of the AIEE committee on rotating machinery. The purpose has been twofold: firstly, to determine how well the actual stray load loss agrees with the standard practice of taking this loss as one per cent of the output power; secondly to seek a more accurate determination of the loss in terms of the load current and the voltage, speed, and size of the machine.