Tests On D.C. Machine

Tests On D.C Machine

Hello All Welcome back to our blog Electrical Online 360°. Today we discuss about the a Swin burn's Test which will be performed at the time of testing of DC Machine. Here we describe full description of Swin burn's Test in this Article.

1 .Swin-Burn's Test

Swinburne's Test (No Load Test / Running Light Test) for D.C. Motor

It is the indirect method of testing a D.C. shunt or compound motor.

In this test, the machine is not loaded actually but the machine is run at no-load. Very large capacity machines which cannot be tested with actual loading can be tested by this method and its performance characteristic is determined by using the data obtained from such test.

Losses and efficiency can be found at a desired load by calculations. This test is also called as no load test or light run test.

Advantages and disadvantages of the Swin burn's Test Mentioned Below:

Advantages Of Swin Burn's Test

1. Suitable for high capacity machine which otherwise cannot be tested with actual loading.
2. Less time is required for testing.
3. Energy is saved in testing.
4. As energy lost during testing is much less. Therefore, excessive heat is not produced as it is the case of testing.
5. Losses and efficiency can be computed for any load condition.
6. Shunt and compound machines can be tested.

Disadvantages Of Swin Burn's Test

1. As machine is not loaded to its full load condition its temperature rise cannot be known.
2. Commutation difficulties cannot be studied.
3. This test cannot be performed on series machine because at no load the speed of the D.C. series motor is dangerously high which may damage the machine mechanically.
4. No account is taken of armature reaction which affects iron losses.
5. The results so obtained are not correct but are approximate.

How To Perform Swinburne's Test (I.E. No Load Test Or Light Run Test) ?

Circuit Diagram Of Swinburne's Test

Procedure Of Swin Burn's Test

1. Connect the appropriate range of the meters with proper polarities as shown in fig.
2. To protect the ammeter from  initial large current, switch 's' is firstly in the closed position.
3. Switch 'on' the supply.
4. Open the switch 's' of ammeter.
5. Adjust the speed to its rated value by rheostat  Rh in the field circuit and keep it constant