(a) In DC motor, quadrant of operation can be defined by the armature voltage and current...

(a)	In DC motor, quadrant of operation can be defined by the armature voltage and current of the motor. By using an appropriate diagram, briefly explain the definition of all four quadrant of operation based on armature voltage and current.

(b)	A chopper is used to control speed of 45.36 kW, 1750 rpm, 240 V, 189 A permanent magnet DC motor with 0.01 Ω armature resistance. This chopper-fed DC motor is able to operate in both motoring and braking mode of operations. Given a chopper input voltage is 240 V and chopping frequency is 400 Hz. Assume that the system operates in continuous conduction mode.
(i)	Sketch the motor-drive circuit as mentioned above and label clearly.

(ii)	Determine the chopper duty cycle during the motoring mode at rated torque with 1000 rpm speed.
(8 marks)
(iii)	If the motor is operated in braking mode, what happened to the armature current, Ia? Determine the chopper duty during the braking mode at rated torque with 400 rpm speed.

Expert Solution

Manojponduru answered 3 years ago

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