Applications of D.C. Motors

D.C shunt motor applications : This motor has approximately constant speed . It can be used for Lathes, Line shafts drives , Centrifugal pumps , Reciprocating pumps, Machine tools ,Blowers , Fans , Grinders , Shapers, Wood working machines , Small printing presses etc.,

                                                        image source Wikipedia                 
                                                
                                                              Centrifugal pumps

D.C series motor applications : Series motor has high starting torque . It can be used for Electric traction, Electric Locomotives , Rapid transit systems , Tram cars, Railway cars, Cranes, Hoists, Elevators, Conveyers etc.,

                                        Image Source alamy.com
                        
                                                       Rapid transit systems 

Cumulative d.c compound motor applications : This motor has variable speed and high starting 
 torque . It can be used for Shears , Punches , Elevators, Conveyors , Heavy planers ,Rolling mills , Ice machines , Printing  presses , Air compressors ,Electric shovels , Metal stamping machines etc.,

Differential d.c. compound motor applications :This motor can be designed to give an accurately constant speed under all conditions.These have limited applications for experimental and research work.

Necessity of Speed control

Ø  Speed control (Definition) :     Intentional variation of speed according to the requirement.

Ø  Mechanically , the speed is varied by using stepped pulleys , set of change gears etc.

Ø  Electrically the speed control of motor having greater advantages over mechanical speed control. D.C motors offer easy speed control & hence dc motors    are widely preferred .

Ø  Hence speed can be changed by varying

                   *      Supply voltage (V)

           *   Resistance of the armature (R_a) 

                  *          The flux per pole (Ф)