Answer Happy

A separately-excited brushed DC motor is supplied with voltage V (volts dc) and draws current I (amperes). The motor has its back emf E, armature resistance Ra back emf constant K, and torque constant KT. Its performance can be summarised in the following figure Motor Speed 600 Rated operating point No load speed Torque-Speed Curve Stall current Max output power Max. efficiency No load current Stall torque Torque load Select the correct statement among the following choices O At the rated current, the motor speed is about half of the no-load speed, i.e. 0.500 O At the maximum efficiency, the motor speed is a half of the no-load speed, i.e. 0.5V Kh V The stall armature current is Irl Кт The no-load speed can be obtained as: wo = E-R₂I Kt At the maximum output power, the motor torque is half of the stall torque, i.e. 0.5Trl.