Characteristics of DC generators

Following are three important characteristics of dc generators :

No load saturation characteristics (E_g V_s I _f)

• It is also called open circuit characteristics or magnetic characteristics. It gives the relationship between no load generated emf in armature E_g and field current I_f
  At gives fixed speed.

• It is just like magnetization curve for the material of the electromagnets.
• Its shape is practically same for all generators whether self. Excited or separately excited.

Internal characteristics(E_g verses I_a)

• It gives the relation between emf generated E_g (after reducing armature reaction drop) and armature current I_a

External characteristics (V versus I_L)

• It gives the relation between terminal voltage V and loads current I_L. This characteristic considers both the drop, armature reaction drop and armature resistance drop on Y axis where terminal voltage is represented.