DC Motors
A dc series motor is that which

Can be started easily without load
Has almost constant speed
Has a poor torque
Has its field winding consisting of thick wire and less turns

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DC Motors
If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens

This will make armature to take heavy current, possibly burning it
This will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses
Motor will come to stop
Nothing will happen to motor

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