The hysteresis and eddy current loss in dc machines running at 1000rpm is 500W and 300W respectively. At what speed will the total iron loss be one-fourth keeping the flux constant.
The hysteresis and eddy current loss in dc machines running at 1000rpm is 500W and 300W respectively. At what speed will the total iron loss be one-fourth keeping the flux constant.
Right Answer is:
333.34 rpm
SOLUTION
Hystresis Losses
Ph ∝ K1n
Eddy current Losses
Pe ∝ K1n2
Total loss = 500 + 300 = 800W
One fourth of the total losses = 800/4 = 200w
$200 = \left( {\frac{{500}}{{1000}}} \right)n + \left( {\frac{{300}}{{{{1000}^2}}}} \right){n^2}$
n = 333.34 rpm