What is megger test and how is it performed?
Megger testing measures resistance between the phase windings of the motor under test and ground. If there is an insulation breakdown, the resistance is negatively impacted and there is a departure between phases or between one measurement and a previous one and a determination of motor health is made.
Can a megger damage insulation?
Using a megger meter is not destructive. When insulation has been damaged, a megger tester is used in determining the cause by testing. The test is typically conducted at rates that are low as compared to the insulation. The insulation tests may range from as low as 40 V dc to 10 kV.
What is the purpose of a Megger test?
The Megger test is a method of testing making use of an insulation tester resistance meter that will help to verify the condition of electrical insulation. Insulation resistance quality of an electrical system degrades with time, environment condition i.e. temperature, humidity, moisture and dust particles.
What is the basic function of a Megger?
Megohmmeter (famous as Megger*) is an electrical instrument used to measure the electrical resistance of insulators. Very often a megger is used to check the insulation of cable jackets, motors, and other high voltage (HV) equipment to ensure the safety of equipment.
What generator is used in a Megger?
A megger uses a DC generator. Thus, we can see that a megger is a quite useful device that has numerous applications. It can be used to measure the resistance of insulators and is also used for testing of devices. It has different variants as well each of which has a different use.
What is the difference between megger and Earth tester?
Difference between megger and earth tester? Megger is an instrument which in addition to measurement of high resistance can be used to test the quality of the insulation at or above its operating voltage. whereas earth tester is used to measure low earth resistance.
Why does Megger use DC voltage?
If we apply DC voltage then as we know Capacitor blocks the flow of DC, only leakage current due to imperfection of insulator will flow and hence the Resistance measured by Megger will actually represent Insulation Resistance. This is the reason, an Insulation Tester or Megger have DC voltage generator.