... . To assure the reliablity of insulation of excitation system, The motor must be protected againse self-indued voltages by a release ... with the field winding when the excitation circuit of the motor is interrupted, At rated field winding resistance(cold). While the ... -times fields resistance. Otherwise higher than seven-times.Raged Speed(rpm): 3000, 1000, 750, 600, 500, 400, 300, 200r/m. Total nine ...