Megger is a portable instrument that is used to measure the insulation resistance of the electrical machinery or system. It can be battery operated or mechanically operated (hand crank dc generator) and gives a direct reading in ohms. It basically works on the principle of electromagnetic induction.
What is the function of megger?
The megger is used to measure a high quantity of insulation resistance. The high resistance may be between the windings of a transformer or motor or between the conductor in a cable and the conduit or sheath enclosing the cable.
What is the working principle of megger Mcq?
Explanation: Megger works on the principle of electromagnetic induction. Supply can be given through a dc motor. A permanent magnet dc motor driven by hand is used as a source of supply to the megger.
What is guard in megger?
The guard terminal is a third connection that is made to the asset under test. This connection provides a return path for the surface leakage current that, as we have seen, can otherwise lead to a substantial error in the insulation resistance measurement.
What is megger Wikipedia?
A Megger consists of an EMF source and voltmeter. The scale of the voltmeter is calibrated in ohms (kilo-ohms or megohms, as the case may be). In measurements, the EMF of the self-contained source must be equal to that of the source used in calibration.
43 related questions foundWhy is it called megger?
One of them was for a "hand dynamo", which allowed generation of voltages high enough to measure resistance in the megohm range and facilitated the construction of the first portable insulation tester. The Megaohm Meter was then named the Megger, and the word became a trademark name, registered on 25 May 1903.
What is megger explain its construction and working?
The Megger has three coils two pressure coils and one current coil. The pressure coil rotates the moving coil in the anticlockwise direction, whereas the current coil rotates it in the clockwise direction. When the unknown resistance is connected in the circuit, the pointer of the moving coil becomes stable.
What is megger value?
The Megger insulation tester is a small, portable instrument that gives you a direct reading of insulation resistance in ohms or megohms. For good insulation, the resistance usually reads in the megohm range.
How many terminals are in megger?
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.
What is insulation tester?
Portable insulation resistance testers and megohmmeters are designed to help prevent hazards such as electric shock and short-circuits caused when the insulation in electrical devices, parts, and equipment used in industrial plants, buildings, and other settings degrades over long periods of use.
How many coils are required in the megger?
The Megger has three coils two pressure coils (control coil) and one current coil. The pressure coil rotates the moving coil in the anticlockwise direction, whereas the current coil rotates it in the clockwise direction.
