A 30 kW, 240 V DC shunt motor has an armature resistance of 0.1 Q. Its field circuit has 80 2 resistance. No-load speed of the machine is 1400 rpm. Mechanical losses (core loss, ventilation loss and friction loss) at 1382,5 rpm are 500 w. a) Find the speeds of the motor for the input currents of 50 A, 75 A and 125 A. b) Draw the torque-speed characteristic of the motor. c) Calculate the value of the resistor which must be added to the field circuit in series to get 1700 rpm at 30 A armature current. d) Calculate the efficiency of the motor for 30 A armature current. P.S. Take the armature current zero at no-load.
A 30 kW, 240 V DC shunt motor has an armature resistance of 0.1 Q. Its field circuit has 80 2 resistance. No-load speed of the machine is 1400 rpm. Mechanical losses (core loss, ventilation loss and friction loss) at 1382,5 rpm are 500 w. a) Find the speeds of the motor for the input currents of 50 A, 75 A and 125 A. b) Draw the torque-speed characteristic of the motor. c) Calculate the value of the resistor which must be added to the field circuit in series to get 1700 rpm at 30 A armature current. d) Calculate the efficiency of the motor for 30 A armature current. P.S. Take the armature current zero at no-load.
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electromechanical energy conversion question. please answer it clearly.
![A 30 kW, 240 V DC shunt motor has an armature resistance of 0.1 2. Its field circuit has 80 2
resistance. No-load speed of the machine is 1400 rpm. Mechanical losses (core loss, ventilation loss
and friction loss) at 1382,5 rpm are 500 W.
a) Find the speeds of the motor for the input currents of 50 A, 75 A and 125 A.
b) Draw the torque-speed characteristic of the motor.
c) Calculate the value of the resistor which must be added to the field circuit in series to get 1700
rpm at 30 A armature current.
d) Calculate the efficiency of the motor for 30 A armature current.
P.S. Take the armature current zero at no-load.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F042f975a-670e-438c-8703-5710f93306ba%2Fe19c7b36-0e4f-45c7-9b3f-9b44f4e5a964%2Fy0mo4qe_processed.png&w=3840&q=75)
Transcribed Image Text:A 30 kW, 240 V DC shunt motor has an armature resistance of 0.1 2. Its field circuit has 80 2
resistance. No-load speed of the machine is 1400 rpm. Mechanical losses (core loss, ventilation loss
and friction loss) at 1382,5 rpm are 500 W.
a) Find the speeds of the motor for the input currents of 50 A, 75 A and 125 A.
b) Draw the torque-speed characteristic of the motor.
c) Calculate the value of the resistor which must be added to the field circuit in series to get 1700
rpm at 30 A armature current.
d) Calculate the efficiency of the motor for 30 A armature current.
P.S. Take the armature current zero at no-load.
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