equivalent circuit of pmdc
As in PMDC motor the field is produced by permanent magnet, there is no need of drawing field coils in the equivalent circuit of permanent magnet dc motor. The supply voltage to the armature will have armature resistance drop and rest of the supply voltage is countered by back emf of the motor. Hence voltage equation of the motor is given by,
Where I, is armature current and R is armature resistance of the motor.
Eb is the back emf and V is the supply voltage.