Spin-Up 3-25

[iahim]

Problem asks for droop if full load speed is set at 59Hz and no load speed at 65Hz.

The solution uses the formula Droop=((f no load - f full load)/f no load) x 100, so result is 9%. In all my references the formula for droop is ((f no load - f full load)/f full load) x 100, so my result was 10.2%. Which formula is correct?

Thanks!

 

[EEpowerOK]

Here is a good discussion on droop and formula

http://cr4.globalspec.com/thread/69707/Droop-of-a-Generator

 

[Ship Wreck PE]

Spin up could be wrong??

 

[spinup]

Problem asks for droop if full load speed is set at 59Hz and no load speed at 65Hz.

The solution uses the formula Droop=((f no load - f full load)/f no load) x 100, so result is 9%. In all my references the formula for droop is ((f no load - f full load)/f full load) x 100, so my result was 10.2%. Which formula is correct?

Thanks!

No Load Frequency = Full Load Frequency X ( 1 + Droop %)

65 = 59 X ( 1 + Droop % )

Droop % = 10.2

Thanks iahim for pointing this out. We will update the errata and make the correction in the next edition.

Joan

 

[iahim]

Thanks iahim for pointing this out. We will update the errata and make the correction in the next edition.

Joan

Thanks Joan! Another problem that I think it's incorrect is 2-04. The autotransformer is clearly a buck, but I don't think the picture show enough info to be able to determine whether it is a step-up or down. It could be either, I think, depending on the turns ratio.