A generator is a device which converts mechanical energy into electrical energy. It has a field winding and an armature winding. A voltage Eg is generated when the eld is excited and there is relative movement between the two windings. The generated voltage varies directly as the speed of relative motion, or frequency, and as the strength of the field. When a generator is operated at no load, the terminal voltage equals the generated voltage. However, as the generator is loaded, the load current flows through the impedance of the armature winding causing a voltage drop which vectorially subtracts from the generated voltage.
Under load the terminal voltage of a generator differs from the generated voltage, depending upon the impedance of the winding and the power factor of the load. Since most loads are lagging, the output of a generator usually drops as load is added. Using a generator voltage regulator, the field strength is varied to vary the generated voltage. The generated voltage is adjusted under load conditions to maintain a constant terminal voltage to feed into the system.
0 comments:
Post a Comment