MEGGER

Description

The megger is used to quantify a large amount of insulating resistance. A high resistance could exist between the windings of a transformer or motor, or between the conductor in a cable and the conduit or sheath that surrounds it.

Megger operates on the electromagnetic attraction principle. When a current-carrying main coil comes into contact with a magnetic field, it experiences a force. This type of force produces torque, which causes the device’s pointer to deflect and provide a reading.

Megger operations

• The needle in the megger is meant to float freely until the generator is turned on. When the generator is turned off, the needle can fall to any point on the scale.
• The megger is used to quantify a large amount of insulating resistance. A high resistance could exist between the windings of a transformer or motor, or between the conductor in a cable and the conduit or sheath that surrounds it.
• The needle moves to infinity when the test leads are connected to the line and earth terminals are open-circuited and a hand-cranked generator is activated. It is too high for the equipment to measure infinity resistance.
• The pointer will drop to zero if the test leads are linked to each other while the hand crank is spun, showing no resistance between the test leads.

Advantages

• Frequent meggering allows us to determine the insulating resistance of electrical equipment; such as motors, transformers, and other similar items, as well as their overall health.
• It can detect physical damage, which could result in an electrical shock if leaks occur.