What is a megger test report?
Table of Contents
What is a megger test report?
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.
What is a normal megger reading?
Anything reading between 2 megohms and 1000 megohms is usually considered a good reading, unless other problems have been noted. Anything less than 2 megohms indicates an insulation problem.
How do you perform a megger test?
How to Use a Megohmmeter
- Cut power. Make sure you eliminate any voltage running through the wires you want to test.
- Uninstall wires. Disconnect the wires you want to test from both ends of the circuit and all feeding wires in motors.
- Connect the ground lead.
- Connect to conductor.
- Build voltage.
- Read meter.
- Complete testing.
What is megger value of motor?
A general rule-of-thumb is 10 Megohm or more.
| Insulation resistance value | Insulation level |
|---|---|
| 2 Megohm or less | Bad |
| 2-5 Megohm | Critical |
| 5-10 Megohm | Abnormal |
| 10-50 Megohm | Good |
How do you megger a 480 volt motor?
IEEE recommends that for motor starting that the operational voltage, expressed as a meg-ohm value doubled plus 1000 is the minimum meg value for starting. For a 480V motor that would mean . 480Meg x 2= . 960 Meg + 1000, so a minimum ground resistance for starting a 480V is 1.960 Meg or round up to 2 meg-ohms.
How many terminals are in a megger?
three connection
How to use Megger. Meggers is equipped with three connection Line Terminal (L), Earth Terminal (E) and Guard Terminal (G). Resistance is measured between the Line and Earth terminals, where current will travel through coil 1.
