Question

A. A four-pole DC shunt generator with a wave wound armature having 390

conductors has to supply a load of 500 lamps each of 100 W at 250 V. Allowing 10 V
for the voltage drop in the connecting leads between the generator and the load and
brush drop of 2 V. Calculate the speed at which the generator should be driven. The
flux per pole is 30 m Wb and the value of Ra = 0.05Ω and Rf = 65Ω

Answer 1

To calculate the speed at which the generator should be driven, we need to consider different factors such as the load requirements, voltage drop, and brush drop.

Step-by-step explanation:

To calculate the speed at which the generator should be driven, we need to consider different factors such as the load requirements, voltage drop, and brush drop. First, we need to calculate the total voltage required by the loads:

• Number of lamps: 500
• Power per lamp: 100 W
• Total power required: 500 lamps * 100 W = 50,000 W
• Voltage per lamp: 250 V
• Voltage required by loads: 500 lamps * 250 V = 125,000 V

Next, we need to consider the voltage drop in the connecting leads and the brush drop. The total voltage drop is given as 10 V + 2 V = 12 V.

Now, let's calculate the total voltage required by the generator:

Total voltage required by generator: Voltage required by loads + Voltage drop = 125,000 V + 12 V = 125,012 V

Finally, we can calculate the speed at which the generator should be driven using the formula:

Speed = (Voltage required by generator / Flux per pole) * (Ra + (Rf / 2))