Handbook of Electrical Engineering

584 HANDBOOK OF ELECTRICAL ENGINEERING

reactances between 15% and 25%, and for motors up to about 15 MW. The main parameter of the

motor is the starting-to-running current ratio, which should not fall below 4 for the extrapolation

to be valid.

The results can be represented in a more comprehensive manner by using a nomograph,

as shown in Figures G.5, 6, 7 and 8. Each nomograph caters for four different starting-to running

current ratios, i.e. 4, 5, 6 and 7. References 1 and 2 describe how to draw a nomograph.

I.9 References

1. Alexander S. Levens, Nomographs. John Wiley & Sons (1948 and 1959). Library of Congress Card No. 59-
   11819.


2. S. Brodetsky, A first course in nomography. G. Bell and Sons Ltd (reprinted 1938).