What happens if a DC Series motor is started without any load?

If a DC series motor is operated at no load, it runs so fast that it destroy itself. The high forces, associated with high speeds, cause the rotor to fly apart, often with disastrous results to people and property nearby. And hence the DC series motor should never be operated at no load.

if we start Dc series motor without  load then it shout more and may get damage itself ............ so in simply words we can say  if applied load its get  quit ........... 

Best regards 

Abdul Razzak

Series motor cannot be started without load because of high starting torque. Also at no load the current passing through the field is minimum

and almost zero ,so the flux at the field will be alsoalmost zero and we know that the speed is inverslyperpotional to the flux in the field so due to almost zeroflux the speed will be maximum and almost infinite at thestarting and it will cause damege of the beerings armaturesshaft due to sudden break in its inertia. 

As we know that, for DC Series motor equation of torque is given by

                               Torque= k*flux*(I)^2

At no load I=0 which means torque=0 and torque is inversely proportional to speed means speed increases rapidly and machine rotates fast enough to damage itself.