The Swinburne test is only applicable for motors where flux is virtually constant, which includes DC shunt and compound motors. The test does not work for series motors because they cannot be run at light loads, and because speed and flux vary significantly in series motors.
Can you conduct Swinburne’s test on a DC series motor?
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.
What are the advantages and disadvantages of Swinburne’s test?
Advantages of Swinburne’s Test :
- The method of testing is a dc machine is simple and convenient.
- It is very economical because the power required is very low and large machines can be tested with a small amount of energy.
- By knowing the losses efficiency at any load can be determined.
Why series motor should not be used for light load condition?
A series motor should never be started at no load. With no mechanical load on the series motor, the current is low, the counter-EMF produced by the field winding is weak, and so the armature must turn faster to produce sufficient counter-EMF to balance the supply voltage. The motor can be damaged by overspeed.
How do you test a DC series motor?
Check to make sure the DC motor’s rotor can turn with no impediments. Switch the voltmeter to “Ohms”. Attach one end of the red lead wires to the DC motor and run the DC motor’s red wire to the battery. Attach the clip of the black lead wire to the DC motor and run the black motor wire to the battery.
Why starters are required in a DC motor?
Starters are used to protect DC motors from damage that can be caused by very high current and torque during startup. They do this by providing external resistance to the motor, which is connected in series to the motor’s armature winding and restricts the current to an acceptable level.
What are the advantages of load test on a motor?
The main advantages of Swinburne’s test are as follows: The power required to test a large machine is small. Thus, this method is an economical and convenient method of testing of DC machines. As the constant loss is known the efficiency can be predetermined at any load.
Why Swinburne’s test is used?
The Swinburne test is an indirect method for determining the efficiency of DC motors. It works by finding the no-load losses experimentally and then estimating additional losses from the rated motor data. From this information, the efficiency can be determined at any applied load.
Which motor has highest no load speed?
Explanation: At no load, armature current tends to zero, flux φ tends to zero, where speed is inversely proportional to the flux, speed will tend to infinity. Thus, no load speed of DC series motor is highest.