Understanding the Effect of Electrical Load on Generator Resistance

[banerjeerupak]

You see i came across this question during my viva in my practical examination. Well the question was that when we increase the electrical load on a genarator, does the resistance in the load increase or go down for the load to increase. we notice that the current remains constant...

 

[brewnog]

On a typical arrangement, when you increase load, the speed drops. This is sensed by the generator's governor; fueling is increased, the speed rises again, and an increased power output is seen.

I don't understand the way you've phrased the question though; if you apply electrical load to the generator output, you apply mechanical load to the prime mover.

Could you clarify?

 

[banerjeerupak]

what i need to know is that there is a power generation plant. there the load is seen to increase. does this mean that the electrical resistances which consume power are being added up in series or in parallel.

 

[russ_watters]

Series or parallel? That doesn't have anything to do with what load the generator sees. Pretty much every house/building has a combination of both.

I'm really not sure what you are asking...

 

[banerjeerupak]

no but which happens when the load is increased...both?

 

[russ_watters]

Which what? What you are asking really makes no sense.

If you flip on a light, regardless of how it is wired, that extra energy being drained from the power grid causes the speed of a generator to slow as brewnog explained.

 

[Codecfault]

I may have interpreted this wrong, but it could possibly be about increasing voltage whilst having the current remain the same and observing the effect on the resistance, ie V=IR

 

[Astronuc]

The speed of the generator determines the voltage.

Increasing load implies increasing the power demand, which means increasing current for a fixed voltage. An increased current would also increase opposing torque on the generator, which slows it down, which lowers the voltage.

If additional load is placed in parallel, then the resistance drops.

On an AC system, one needs to consider resistive and reactive loads.