Describe the voltage vs. load current characteristics for a flat-compounded, over-compounded, and under-compounded DC generator.
In practical compounded generators, the change in output voltage from no-load to full-load is less than 5 percent. A generator with this characteristic is said to be flat-compounded
For some applications, the series winding is wound so that it overcompensates for a change in the shunt field. The output gradually rises with increasing load current over the normal operating range of the machine. This type of generator is called an over-compounded generator.
The series winding can also be wound so that it under compensates for the change in shunt field strength. The output voltage decreases gradually with an increase in load current. This type of generator is called an under-compounded generator.