A Comparison of the Performance of a Direct Current Generator With That Calculated from its Dimensions

The design of electrical machinery when undertaken as a thesis is usually done in the same order as in commercial work. The desired performance is specified. The electrical and mechanical dimensions are then calculated with the view of producing this performance. This method for a thesis is defective where the machinery, as is usually the case, Can- not be built, because there is no way of judging the merits of the design.

For these reasons in the present case the order of procedure is reversed. The electrical and mechanical dimen- sions are taken from a completed machine of the following rating: -

Crocker Wheeler Co.,

Type C. M. Size 10 D.

Output 13 H. P.

1175 R. P. M.

Volts 500

Amperes 22

The process of design was then gone through in the reversed order, the performance of the machine being predicted in detail from its dimensions. When this was done and curves plotted the machine was tested and the actual curves plotted on the same sheet for the purpose of comparison.