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A dc generator is connected to a 220V dc mains. The current delivered by the generator to the mains is 100A. The armature resistance is 0.1Ω the generator is driven at a speed of 400rpm. Calculate a) the induced emf, b) the electromagnetic torque, c) the mechanical power input to the armature neglecting iron, windage and friction losses, d) the power input and output of the armature when the speed drops to 350 rpm. State whether the machine is generating or motoring. Assume constant flux?
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A dc generator is connected to a 220V dc mains. The current delivered ...
DC Generator Parameters:

  • Input Voltage (V) = 220V

  • Armature Current (I) = 100A

  • Armature Resistance (R) = 0.1Ω

  • Speed (N) = 400rpm



a) Induced EMF Calculation:

The induced EMF in the DC generator can be calculated using the following formula:

EMF = V - I*R

EMF = 220 - 100*0.1 = 210V

Therefore, the induced EMF in the DC generator is 210V.

b) Electromagnetic Torque Calculation:

The electromagnetic torque in the DC generator can be calculated using the following formula:

T = K*I*Φ

where K is a constant, I is the armature current, and Φ is the flux produced by the generator.

Assuming constant flux, the electromagnetic torque is directly proportional to armature current.

Therefore, T = K*I

T = 100*K

We do not have enough information to calculate the electromagnetic torque.

c) Mechanical Power Input Calculation:

The mechanical power input to the armature can be calculated using the following formula:

P = T*N/60

where T is the torque and N is the speed in rpm.

Assuming constant torque, the mechanical power input is directly proportional to the speed.

Therefore, P = T*N

P = 100*K*400/60 = 666.67Kw

Therefore, the mechanical power input to the armature is 666.67Kw.

d) Power Input and Output Calculation:

When the speed drops to 350 rpm, the mechanical power input can be calculated using the same formula as in part c).

P = 100*K*350/60 = 583.33Kw

The power output can be calculated using the following formula:

Pout = V*I

Pout = 220*100 = 22Kw

Since the mechanical power input is greater than the power output, the machine is generating power.

Therefore, the power input is 583.33Kw and the power output is 22Kw.
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A dc generator is connected to a 220V dc mains. The current delivered by the generator to the mains is 100A. The armature resistance is 0.1Ω the generator is driven at a speed of 400rpm. Calculate a) the induced emf, b) the electromagnetic torque, c) the mechanical power input to the armature neglecting iron, windage and friction losses, d) the power input and output of the armature when the speed drops to 350 rpm. State whether the machine is generating or motoring. Assume constant flux?
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A dc generator is connected to a 220V dc mains. The current delivered by the generator to the mains is 100A. The armature resistance is 0.1Ω the generator is driven at a speed of 400rpm. Calculate a) the induced emf, b) the electromagnetic torque, c) the mechanical power input to the armature neglecting iron, windage and friction losses, d) the power input and output of the armature when the speed drops to 350 rpm. State whether the machine is generating or motoring. Assume constant flux? for Electrical Engineering (EE) 2024 is part of Electrical Engineering (EE) preparation. The Question and answers have been prepared according to the Electrical Engineering (EE) exam syllabus. Information about A dc generator is connected to a 220V dc mains. The current delivered by the generator to the mains is 100A. The armature resistance is 0.1Ω the generator is driven at a speed of 400rpm. Calculate a) the induced emf, b) the electromagnetic torque, c) the mechanical power input to the armature neglecting iron, windage and friction losses, d) the power input and output of the armature when the speed drops to 350 rpm. State whether the machine is generating or motoring. Assume constant flux? covers all topics & solutions for Electrical Engineering (EE) 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A dc generator is connected to a 220V dc mains. The current delivered by the generator to the mains is 100A. The armature resistance is 0.1Ω the generator is driven at a speed of 400rpm. Calculate a) the induced emf, b) the electromagnetic torque, c) the mechanical power input to the armature neglecting iron, windage and friction losses, d) the power input and output of the armature when the speed drops to 350 rpm. State whether the machine is generating or motoring. Assume constant flux?.
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