Three point starter

Three point starter Points : Three point starter, Definition Three point D.C starters are used for starting of D.C shunt motor. Two factors limit the current taken by a motor armature from a D.C source.
(1)The back e.m.f.
(2) The armature resistance.
When armature is at a stand still position, there is no back e.m.f in it and in this position the current taken by armature will be abnormally high. Therefore, the armature current must be limited by an external. resistor, such as a starting resistor. In addition, a motor starter limits the current in the armature circuit to a safe value during the starting period. Therefore we use three point starters for this purpose.