There are THREE types of losses in a.d.c. motor: Iron loss, copper loss and mechanical loss.
i. Iron loss:- These are losses arising from the magnetic circuit of the machine and are of two types namely eddy current and hysteresis losses.
ii. Copper Loss: These losses are due to the flow of current through the copper conductors of the motors and are sometimes termed 1²R losses.
iii. Mechanical loss:- These are made of bearing friction and windage. This is a friction loss due to the movement of the armature through air.
