Motor Generator Set | M G Set

A motor generator (M-G) set refers to a composite device consisting of a motor and a generator mechanically coupled through the common shaft. Practically a motor generator set is a system where a motor and a generator are connected or rather placed in a single circuit. It is a device used to convert electrical power from one form to another. That is mainly it converts electrical power to any other type of power.Motor Generator Set Motor generator set are also used to convert voltage, phase and frequency of power. They also find application in isolation of electrical loads from the supply line. Here is a pictorial representation of a MG set.

Here a motor and a generator are coupled together using a single shaft; they are wound around a single rotor. Necessary condition for coupling is that rated speed of both motor and generator should be same.
The diagram of a motor generator set is shown below, motor generator set

Working Principle of Motor Generator Set

From the above diagram we can see that in a typical motor generator set, the power is given externally to a motor and as a result the shaft of the motor rotates the rotor of the generator. That means, motor receives electrical energy input from the supply line. Its shaft rotates and since the generator shaft is mechanically coupled with it, the generator also receives its mechanical input through shaft. Thus generator also creates electrical output power or in other words generator converts the mechanical energy into electrical energy. Thus while the power at the input as well as output side is electrical in nature, the power flowing between the machines is in the form of mechanical torque. This provides isolation of the electrical system as well as some buffering of power between the two electrical systems.


The motor generator set can be used for conversions of electrical power in various forms
    1. AC to DC – This is possible by using an AC motor (induction motor or synchronous motor) and a DC generator.
    2. DC to AC – This can be accomplished by using a DC motor and an AC generator.
    3. DC at some voltage level to DC at another voltage level.
    4. Alternating power at one frequency to Alternating power at another frequency
    5. Fixed AC voltage to variable or regulated AC voltage
    6. Single phase AC voltage to 3 phase AC voltage

Now days motor generator sets have been upgraded in many ways. Earlier these were used in the places where speed regulation is required highly like elevators, factories etc. Now a day’s semiconductor devices are working as the motor generator set i.e. with the introduction of power semiconductors devices like thyristor or SCR?">thyristor, GTO, MOSFET etc. motor generator set are replaced by them. These conversions of power from one form to another can be brought about very easily. They are small and compact in size, losses are less and control is very easy.

Closely Related Articles Alternator Synchronous Generator | Definition and Types of AlternatorWorking Principle of AlternatorConstruction of AlternatorArmature Reaction in Alternator or Synchronous Generator Rating of AlternatorDerivation of Various Power Conditions in Alternators and Synchronous MotorsInduction Generator | Application of Induction GeneratorParallel Operation of AlternatorMore Related Articles Principle of DC GeneratorConstruction of DC Generator | Yoke Pole Armature Brushes of DC GeneratorCharacteristics of Series Wound DC GeneratorCharacteristic of Separately Excited DC GeneratorEMF Equation of DC GeneratorParallel Operation of DC GeneratorsSelf Excited DC GeneratorsHopkinson TestPhasor Diagram for Synchronous GeneratorDC Generators Performance CurvesTypes of DC GeneratorsCharacteristic of Shunt Wound DC GeneratorMagnetization Curve of DC GeneratorApplications of DC GeneratorsArmature Winding | Pole Pitch Coil Span Commutator PitchWave WindingWinding Factor | Pitch Factor | Distribution FactorLap Winding Simplex and Duplex Lap WindingFrog Leg Winding | Drum Winding | Gramme Ring WindingArmature Winding of AlternatorNew Articles Series and Parallel Inductors Electric PowerMeasurement of Losses in Shunt ReactorThree Phase Shunt ReactorMeasurement of Insulation ResistanceAmpere's Circuital Law
electrical engineering app