PPT Slide

Section 13.5: Performance Equations cont.

Example 13.5 cont.

The field current is If = Vt/Rf = 250V./125W = 2A. so (by KCL), the armature current at no-load is: Ia = I - If = 5A.- 2A. = 3A.

By KVL, ENL = Vt - RaIa = 250V. - 0.25W´3A. = 249.25V.

and the corresponding (no-load) speed is nNL = 1200 RPM