How to use the Megger ?

The principle of operation of the device

Megaohmmeter generates a voltage own a high-voltage converter, and milliamp records current in the measuring circuit.From school physics course we know Ohm's law, and the relationship between resistance R, which is equal to U divided by I.

Currently widely used digital meters instruments, due to its compactness and lightness, but along with them still run the model with arrowmanual dynamo.Now we look at how to use the Megger old-style and new.

draw your attention to the fact that some have called a device for measuring insulation resistance Megger.This is not quite the right name, becauseif the word is broken down by parts, the prefix "mega" unit "Om" and "meter" (translated from the Greek as a measure).

Instructions

insulation resistance check is performed on de-energized equipment or cabling, wiring.Remember that the device generates a high voltage and in violation of security measures on the use of electro-megaohmmeter possible becauseInsulation measurement capacitor or cable line long distance can cause dangerous accumulation of charge.Therefore, the test is carried a crew of two people having an idea about the dangers of electric current and received TB approval.During the test object must not be close to unauthorized persons.Remember about high voltage.

instrument for each use is inspected for integrity, the absence of chipping and damaged insulation on the measuring probes.Produced trial testing by testing with diluted probes and closed.If the test produces a mechanical device, it is necessary to place it on a flat level surface to avoid measurement errors.If the insulation resistance measurement Megger need old-style handle to rotate the generator at a constant speed of about 120-140 rpm.

If we measure the resistance relative to the housing or land, employ two probes.When producing test cable cores to each other, you need to use the terminal "E" megger and the cable shield to compensate for leakage currents.

Insulation resistance is not fixed and depends largely on external factors, so it may vary during the measurement.Check is made at least 60 seconds from 15 seconds to record the readings.

For domestic network test voltage of 500 volts are produced.Industrial networks and devices are tested voltage in the range of 1000-2000 volts.What is the limit of measurement to use, it is necessary to know the operating instructions.The minimum allowable resistance value for networks of up to 1000 volts - 0.5 MW.For industrial devices no less - 1M.

As for the measurement technology needed to use megger by the method described below.For example, we have a situation with the measurement of insulation in mc (power board).Thus, the procedure is the following:

1. people out of the inspected parts of the installation.Hazard warning post warning signs.
2. relieves stress, de-energizes fully shield the opening cable, take action on the incorrect supply voltage.Carried banners - do not include working people.
3. Check absence of voltage.Pre grounding terminals of the test object, set the test leads as shown in the wiring diagram megaohmmeter and remove ground. This procedure is carried out at each new metering as the nearby elements can accumulate charge, make an error in the readings and be life-threatening.Installation and removal of probes made by insulated gripping rubber gloves.We draw your attention to the fact that the insulating layer of the cable before checking the resistance should be cleaned from dust and dirt.
4. Check the insulation of the cable opening between the phases A, B, C, C, A, A-PEN, B-PEN, C-PEN.The results are recorded in the measurement protocol.
5. Turning off all machines, RCD, switchable lamps and lighting fixtures, disconnect the wires from zero zero terminals.
6. produce measurement between each phase line and N, phase and PE, N and PE.Results are making in the measurement protocol.
7. In the case of a defect of the parse measured on components, looking for the fault and eliminate.

After testing portable grounding remove residual charge from the object by a short circuit and the measuring device itself, discharging the probes together.It is for such instructions must be used when measurements Megger insulation resistance of cable and other lines.To make it more clear information below, we have provided a video which clearly demonstrates how the measurements when working with certain models of devices.

Tutorials

First offer to your attention a manual dial megaohmmeter ES0202 / 2-G:

Another popular dial gauge, which is similar to the above model - m4100.Using them is also quite simple, as you can see by looking at this video:

Digital testers with an even easier-to-use display.For example, take a measurement UT512 UNI-T cable insulation resistance meter can modern technology for this:

Well, the last instruction concerns another popular device - E6-32.The video below shows in detail how to use the Megger to measure the insulation resistance of the transformer, cable and even metallosvyazi:

Here on this procedure is carried out insulation resistance measurement Megger.As you can see, to use this device is not difficult, but you need to get serious about safety and take all the necessary measures of protection.

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