(a) Describe how a three-phase brushless DC (BLDC) motor differs in construction from a separately excited brushed DC mo

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A Describe How A Three Phase Brushless Dc Bldc Motor Differs In Construction From A Separately Excited Brushed Dc Mo 1 (32.69 KiB) Viewed 27 times

(a) Describe how a three-phase brushless DC (BLDC) motor differs in construction from a separately excited brushed DC motor. (b) Assume that the back emf waveform of each phase of a BLDC motor is a trapezoidal waveform with 120 degree (electrical) duration of constant amplitude in each half cycle. Explain, with the help of suitable sketches of phase back emfs, how phase currents must be switched so that the brushless DC motor develops a constant torque per Ampere characteristic like a separately excited brushed DC motor. (c) A three-phase inverter delivers regulated three-phase currents to the BLDC motor. Explain, with the help of a suitable sketch how regulated phase currents are delivered to the motor.