Need Help In Electric Power

[shermaine]

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.

 

[IRQ57]

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