Megger

May 25, 2024 Post a Comment

Megger

A megohmmeter, or megger, is a device used to test electrical and insulation resistance. This is usually done by sending a high-voltage signal into the object being tested, typically a wire or motor. Using a megger is important for avoiding electric shock and equipment damage.

What is Megger test?

Megger testing is an electrical test of insulation performance in an electrical apparatus. A mega-ohm meter is applied to each phase connection for the motor leads and ground, and a voltage applied.

What is Megger in simple words?

/ (ˈmɛɡə) / noun. trademark an instrument that generates a high voltage in order to test the resistance of insulation, etc.

How does a Megger test 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.

What is working principle of megger?

Megger works on the principle of electromagnetic attraction. When a primary coil that is carrying current is placed under the vicinity of a magnetic field it experiences a force. This kind of force generates a torque that is made to deflect the pointer of the device which gives some reading.

Is a megger AC or DC?

The megger has a DC generator inside it. The DC generator may be of manual type of or electronic. It generates a high DC voltage.

What is IR value?

An insulation resistance (IR) test measures the total resistance between any two points separated by electrical insulation. The test, therefore, determines how effective the dielectric (insulation) is in resisting the flow of electrical current.

What is megger range?

The Megger dC dielectric Test Sets are available with voltage outputs ranging from 5 kV up to 160 kV.

What is the minimum megger value?

The rule states that insulation resistance should be approximately one megohm for each 1000 volts of operating voltage, with a one megohm minimum. (By following this rule, a motor rated at 2400 volts should have a minimum insulation resistance of 2.4 megohms).

Why megger is used instead of multimeter?

Megger is used to test the insulation resistance of a conductor while multimeters are used to measure the voltage,current and resistance of a circuit.

Can megger measure 1000 ohms?

It is also known as mega-ohm-meter. It is used in several areas like multi-meters, transformers, electrical wiring, Etc. Megger device is for testing various electrical devices that can measure greater than 1000 meg-ohms. It consists of both a generator and an ohmmeter.

What is the good value of megger?

Insulation resistance value	Insulation level
5-10 Megohm	Abnormal
10-50 Megohm	Good
50-100 Megohm	Very good
100 Megohm or more	Excellent

What is the unit of Megger?

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.

What are the two types of Megger?

There are two types of meggers, manual and electrical megger. The main concept of megger is to measure insulation resistance and machine windings.

Why Megger output is DC?

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.

Which motor is used in megger?

Hand driven PMDC generator is used in this test.

Why megger is called megger?

One of them was for a "hand dynamo", which allowed the 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 IR in current?

The trip-current setting Ir or Irth (both designations are in common use) is the current above which the circuit-breaker will trip. It also represents the maximum current that the circuit-breaker can carry without tripping.

Why we do IR test?

Insulation resistance (IR) is a measurement of how good or bad your insulation is, which can help give you an overall assessment of your electrical equipment's health. By the way, no insulation is perfect—with infinite resistance—but good insulation has a relatively high resistance to current.

Why IR value is important?

'Good' insulation means a relatively high resistance to current and also the ability to maintain that high resistance over time. So, measuring insulation resistance (typically referred to as 'IR') regularly could indicate how “good” the insulation is and can also check trends toward its deterioration.