DC Servo-Motor Ra G I,=constant R3=armature resistance,2电枢电阻 i=field current,A La=armature inductance,H,电枢电感 激磁电流 ia=armature current,.A,电枢电流ea B La If=constant Ra eb T J  ia Ra=armature resistance,  电枢电阻 La=armature inductance, H, 电枢电感 ia=armature current, A, 电枢电流 if=field current, A 激磁电流 DC Servo-Motor