Applications of DC Machines – Motors and Generators

In the present day world, electrical energy is generated in bulk in the form of an alternating current. Hence, the use of DC machines, i.e., DC generators and motors are very limited. They are mainly used in supplying excitation of small and medium-range alternators. The Industrial Applications of DC Machines are in Electrolytic Processes, Welding processes and Variable speed motor drives.

Nowadays, the alternating current is generated first and then it is converted into DC by the rectifiers. Thus, DC generator has generally been suppressed by a rectified AC supply for many applications.

Direct current motors are very commonly used as variable speed drives and in applications where severe torque variations occur.

Applications of DC Motors

The main applications of the three types of direct current motors are given below.

Series Motors

The series DC motors are used where high starting torque is required and variations in speed are possible. For example – the series motors are used in the traction system, cranes, air compressors, Vaccum Cleaner, Sewing machine, etc.

Shunt Motors

The shunt motors are used where constant speed is required and starting conditions are not severe. The various applications of DC shunt motor are in Lathe Machines, Centrifugal Pumps, Fans, Blowers, Conveyors, Lifts, Weaving Machine, Spinning machines, etc.

Compound Motors

The compound motors are used where higher starting torque and fairly constant speed is required. The examples of usage of compound motors are in Presses, Shears, Conveyors, Elevators, Rolling Mills, Heavy Planners, etc.

The small DC machines whose ratings are in fractional kilowatt are mainly used as control device such in techno generators for speed sensing and in servo motors for positioning and tracking.

Applications of DC Generators

The applications of the various types of DC Generators are as follows:-

Separately Excited DC Generators

  • Separately excited DC Generators are used in laboratories for testing as they have a wide range of voltage output.
  • Used as a supply source of DC motors.

Shunt wound Generators

  • DC shunt-wound generators are used for lighting purposes.
  • Used to charge the battery.
  • Providing excitation to the alternators.

Series Wound Generators

  • DC series wound generators are used in DC locomotives for regenerative braking for providing field excitation current.
  • Used as a booster in distribution networks.
  • Over compounded cumulative generators are used in lighting and heavy power supply.
  • Flat compounded generators are used in offices, hotels, homes, schools, etc.
  • Differentially compounded generators are mainly used for arc welding purpose.

This is all about applications of DC machines.

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