A d.c. self-excited shunt generator has a field resistance of 160Ω. The generated emf is 420V and it supplies a load of 55kW Calculate the armature resistance when the generator terminal voltage is 408V

Can anyone please give me a heads up?

Thanks

 

Hi,

I'll take a quick guess at this in case no one else wants to post. I didnt look anything up yet though.

You have the source voltage and the load voltage, and the total load resistance of which part you can calculate by the given load power, and you have the armature resistance. So you have one source and three resistances, and one of those resistances (the armature resistance) you have to calculate. So you are given a lot of information here. Can you figure out how to arrange the components to form a circuit and then calculate the unknown resistance?

 

"A d.c. self-excited shunt generator has a field resistance of 160Ω. The generated emf is 420V and it supplies a load of 55kW"

Draw that out and label knowns. Where does the current come from? Where does it go? With those knowns......figure all legs of current. Now you can figure armature current and resistance.
Now change only one of the knowns.....420 to 408. Re figure.