Temperature rise values for D-C machines: An AIEE committee report

FIVE manufacturers have tested motors rated at 0.5, 5, 10, 25, and 50 horsepower for temperature rise on an exchange motor test program at the request of the AIEE committee on rotating machinery. The purpose was to determine the relation between the internal hot-spot temperature rise and the temperature rise measured by the resistance method, thermometer method, and surface thermocouple method. These relations were determined for both continuous-load heat runs and for short-time heat runs. The motors tested were all general-purpose, open 40 degree centigrade, 1,750-rpm motors.