What Walsin diesel generator set manufacturers describe here is the load characteristics of synchronous generator sets, because it is directly connected to the load. This has been explained in the working principle of the synchronous generator in the technical support column: after the rotor winding is fed with the DC current provided by the rotating rectifier, a magnetic field is generated in the air gap between it and the stator, which is called the rotor magnetic field or the main magnetic field. Then the stator or armature winding connected to the load will also generate a magnetic field in this air gap due to the flow of the load current, which is called the stator or armature magnetic field. These two magnetic fields in the air gap naturally work together to form a combined magnetic field. The size of the output voltage and current of the synchronous generator is determined by it.

The main reason for the change of the synthetic magnetic field is that the armature magnetic field changes due to the different nature of the load. This is called armature reaction: when the armature winding of the generator, which is in principle an iron-core inductive coil, is only connected to a purely resistive load, the potential of the winding is in phase with the current, and the armature magnetic field is superimposed with the rotor magnetic field, resulting in a combined magnetic field. Nothing has changed. It's just that when the generator is running with load, its stator magnetic flux needs to be in a saturated state to absorb some armature magnetic field, so that the combined magnetic field is slightly reduced. The larger the load current, the more the reduction will be.

If the armature winding is only connected to a purely inductive load, the armature current should lag the potential by a phase angle of 90°. The armature magnetic field generated by this current will counteract the rotor magnetic field, thereby weakening and distorting the resultant magnetic field. The output voltage of the generator is thus reduced.

If only a purely capacitive load is connected to the armature winding, then due to the nature of the capacitance, the current of the armature winding will be 90° ahead of its potential by a phase angle. The armature magnetic field formed by this current can strengthen the rotor magnetic field, which strengthens the combined magnetic field and increases the output voltage of the generator.

The above analysis shows that the three loads of different nature will make the synchronous generator produce different armature reactions, and then its output voltage will change. By mastering these laws, you can configure a better load for the diesel generator set, so that the unit can exert its full potential and provide excellent electrical energy.