Resistance of Earth
Arc Suppression Coil or Petersen Coil
Winding Resistance Test of Shunt Reactor
Measurement of Reactance of a Shunt Reactor
Tests of Shunt ReactorClosely Related Articles
DC Motor or Direct Current Motor
Speed Regulation of DC Motor
Speed Control of DC Motor
Working or Operating Principle of DC Motor
Torque Equation of DC Motor
Construction of DC Motor | Yoke Poles Armature Field Winding Commutator Brushes of DC Motor
Testing of DC Machine
Swinburne Test of DC Machine
Losses in DC Machine
Ward Leonard Method of Speed Control
Armature Reaction in DC Machine
Commutation in DC Machine or Commutation in DC Generator or Motor
Methods of Improving Commutation
Starting Methods to limit Starting Current and Torque of DC Motor
3 Point Starter | Working Principle and Construction of Three Point Starter
4 Point Starter | Working Principle and Construction of Four Point Starter
Electrical Motor | Types Classification and History of Motor
Working of Electric Motor
Types of DC Motor Separately Excited Shunt Series Compound DC Motor
Shunt Wound DC Motor | DC Shunt Motor
Series Wound DC Motor or DC Series Motor
Compound Wound DC Motor or DC Compound Motor
Permanent Magnet DC Motor or PMDC Motor | Working Principle Construction
Brushless DC Motors
Swinburne Test of DC Machine
Calculation of EfficiencyLet, I0 is the no load current (it can be measured by ammeter A1) Ish is the shunt field current (it can be measured by ammeter A2)
Then, no load armature current = Also let, V is the supply voltage. Therefore, No load power input = VI0 watts. In Swinburne's test no load power input is only required to supply the losses. The losses occur in the machine mainly are: Iron losses in the core Friction and windings losses Armature copper loss. Since the no load mechanical output of the machine is zero in Swinburne's test, the no load input power is only used to supply the losses. The value of armature copper loss = Here, Ra is the armature resistance. Now, no to get the constant losses we have to subtract the armature copper loss from the no load power input. Then, After calculating the no load constant losses now we can determine the efficiency at any load. Let, I is the load current at which we have to calculate the efficiency of the machine. Then, armature current (Ia) will be (I - Ish), when the machine is motoring. And , when the machine is generating.
Calculation of Efficiency When the Machine is Motoring on LoadPower input = VI Armature copper loss, Constant losses, ∴ Efficiency of the motor:
Calculation of Efficiency When the Machine is Generating on LoadPower input = VI Armature copper loss, Constant losses, ∴ Efficiency of the generator:
Advantages of Swinburne's TestThe main advantages of this test are:
- This test is very convenient and economical as it is required very less power from supply to perform the test.
- Since constant losses are known, efficiency of Swinburne's test can be pre-determined at any load.
- Iron loss is neglected though there is change in iron loss from no load to full load due to armature reaction.
- We cannot be sure about the satisfactory commutation on loaded condition because the test is done on no-load.
- We can’t measure the temperature rise when the machine is loaded. Power losses can vary with the temperature.
- In DC series motors, the Swinburne’s test cannot be done to find its efficiency as it is a no load test.
Disadvantages of Swinburne's TestThe main disadvantages of this test are :
Closely Related Articles DC Motor or Direct Current MotorSpeed Regulation of DC MotorSpeed Control of DC MotorWorking or Operating Principle of DC MotorTorque Equation of DC MotorConstruction of DC Motor | Yoke Poles Armature Field Winding Commutator Brushes of DC MotorTesting of DC MachineLosses in DC MachineWard Leonard Method of Speed ControlArmature Reaction in DC MachineCommutation in DC Machine or Commutation in DC Generator or MotorMethods of Improving CommutationStarting Methods to limit Starting Current and Torque of DC Motor3 Point Starter | Working Principle and Construction of Three Point Starter4 Point Starter | Working Principle and Construction of Four Point StarterMore Related Articles Electrical Motor | Types Classification and History of MotorWorking of Electric MotorTypes of DC Motor Separately Excited Shunt Series Compound DC MotorShunt Wound DC Motor | DC Shunt MotorSeries Wound DC Motor or DC Series MotorCompound Wound DC Motor or DC Compound MotorPermanent Magnet DC Motor or PMDC Motor | Working Principle ConstructionBrushless DC MotorsNew Articles System EarthingArc Suppression Coil or Petersen CoilWinding Resistance Test of Shunt ReactorMeasurement of Reactance of a Shunt ReactorTests of Shunt Reactor