Conditions for Self Excitation

Conditions for Self Excitation Points : Conditions for Self Excitation D.C. Generator 1. There must be some residual magnetism in the field system.
2. The residual magnetism must be in proper direction. The field coils should be connected with the armature in such a way that current flowing through them should increased the emf induced by the residual magnetism.
3. For a series wound generator, the resistance of the external circuit should be less than the critical resistance.
4. For a shunt wound generator, resistance in the field circuit must be less than critical resistance for field circuit and resistance in the load circuit must be greater than critical resistance for the load circuit.