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What is Megger ohm meter?

What is Megger ohm meter?

A Megohmmeter or insulation resistance tester is a special type of ohmmeter used to measure the electrical resistance of insulators.

What is a Megger used for?

A megger is used to measure insulation resistance and it is powered by a inbuilt DC generator or battery of a higher voltage range, it is called Megohmmeter.

How does a Megger differ from ohm meter?

The chief advantage of the megger over an ohmmeter is its capacity to measure resistance with a high potential or breakdown voltage. Impedence of insulation is very high. A megger is specifically designed to accurately measure high impedences. An ordinary multimeter is designed to measure lower, more finite impedences.

Why is it called a 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.

How is megger test performed?

To check whether connections are made perfectly, we use an electrical instrument named megger. In an insulation testing, we send a test voltage down through an electrical system, to check if there is any leakage of current which is gone to be passed through the insulated wiring of all the appliances of the machine.

Which is the important part of megger?

The important parts in electronic type megger are digital display, wire leads, selection switches and indicators. The digital display shows the value of insulation resistance in digital form.

Why DC is used in megger?

The accurate insulation resistance can be done if the DC voltage is applied to measure the megger value. That is why a megger has DC generator.

What is the minimum megger value?

1. IR Values For Electrical Apparatus & Systems

Max.Voltage Rating Of Equipment Megger Size Min.IR Value
600 Volts 1,000 Volts 100 MΩ
5 KV 2,500 Volts 1,000 MΩ
8 KV 2,500 Volts 2,000 MΩ
15 KV 2,500 Volts 5,000 MΩ

What is the normal speed of megger?

The speed of megger is kept around at 160 rpm.

What is a good 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 does a megger measure resistance?

The Megger insulation tester is essentially a high-range resistance meter (ohmmeter) with a built-in direct-current generator. This meter is of special construction with both current and voltage coils, enabling true ohms to be read directly, independent of the actual voltage applied.

How many coils is used in megger?

three coils
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.