A 500-hp 600-volt compound motor operates at a speed of 495 rpm at full load. If the flux per pole is 8.9 x 10^6 maxwells and the armature resistance is 0.015 ohm, calculate the following (Assume a value of k=1.28 x 10^-7 and a brush drop of 5 volts).
If the load on the motor is increased so that the armature current rises to 789 amps, at what speed will the motor operate, assuming that the flux increases 8 percent?
When the load is removed, the speed rises to 600 rpm. What is the regulation of the motor?