Need Help In Electric Power

Here's one exam question....
Can any one help me?
The induced voltage of a separtely excited DC generator is 230V at a speed of 1000rpm when the filed current is 1.25A. Assume that the filed flux is directly proportional to the filed currents If.....Determine
(1) induced voltage for a filed current 1.1A at 1200rpm
(2) Speed in rpm when the induced voltage is 210V for a field current of 1.2A
(3) field current at 1200 rpm for an induced voltage of 205V

Pls advise.

DC generator

Hello,

In this generator the voltage induced for each RPM at a field current of 1 A will be:

230 V
_______________ = 0.184 V / (RPM x A)

1000 RPM x 1.25 A

Then:

(1) V= 0.184 x 1200 x 1.1 = 242.88 V

(2) RPM = 210 / (0.184 x 1.2) = 951 RPM

(3) Field C. = 205 / (1200 x 0.184) = 0.928 A


Regards