The dc motor, which can provide zero speed regulation at full load without any controller is

In a $$DC$$ machine, which of the following statements is true?

A dc series motor fed from rated supply voltage is overloaded and its magnetic circuit is saturated. The torque-speed characteristic of this motor will be approximately represented by which curve of Fig.

In case of an armature controlled separately excited dc motor drive with closed loop speed control, an inner current loop is useful because it