How to use a meger

how to use a meger

How-to Megger a Motor

Place the positive and negative probes of the Megger on the two conductors or terminals between which you are testing the insulation resistance. If you are testing insulation resistance to ground, place the positive probe on the ground wire or the grounded metal junction box and the negative probe on the conductor or terminal. Jan 11,  · Very often a megger is used to check the insulation of cable jackets, motors, and other high voltage (HV) equipment to ensure the safety of equipment. During its working, the object under test is connected with the probes (terminals) of megger and voltages are generated, usually, these voltages are between 1kV – 5kV.

Megger is a registered trademark, not a verb, but we get it — old habits die hard. And that is a question we can definitely help you with, regardless of whether you say Megger, megging, or meg a motor. To each their own, right? Plus, this is a blog, not a lecture hall. However, despite what development sparked the cuban missile crisis of 1962 manufacturing improvements to motors over the years, insulation is still susceptible to classic wear and tear, as well as other villains like mechanical damage, vibration, excessive heat or cold, dirt, oil, corrosive vapors, moisture from processes, or just natural humidity, which can cause insulation failure.

Over time, these rascals cause tiny holes and cracks, allowing moisture or foreign particles to leak into the surface of the insulation — giving way to a low resistance path for leakage current.

Typically, the resistance drop is gradual though, which is where electrical testing comes in! By the way, good insulation has a high resistance, whereas poor insulation has a relatively low resistance. With a preventative maintenance plan, you can schedule reconditioning or repairs before complete service failure. If you like saving money and preventing down how to use a meger, then this one is for how to cook tenderloin of pork For AC motors and starting equipment, check out the below diagram from A Stitch in Time — our complete guide to insulation resistance testing.

You can also test the rigging and field coils separately, from the armature itself. While there are guides and rules for minimum values of insulation resistance, your best indication of trouble in paradise is a consistent downward trend in IR measurements.

Blog December How-to Megger a Motor. How-to Megger a Motor 17 December Why would you need to Megger a motor? Or better yet… Why should you be running insulation resistance tests on your motor? Now, for the main event. How can you run an insulation test on a motor? So, you ran your test, now what? How do you interpret resistance readings?

But the biggest recommendation we can give you is as follows… Periodic testing is key. We use cookies to provide you with a better experience. Read more on our cookie policy.

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Aug 03,  · The megger must be calibrated before any testing, for conducting test a megger with a range of V/V must be used. In order to do a wire testing, a megger that has V range is used, and to do a cable testing, a V range megger is used. So by testing an electrical device by using a megger we can make sure of electrical safety. Jan 22,  · Clamp the alligator clip on one of the megger probes to the wire or cable, touch the other probe to the exposed conductor and press the test button. The megger will generate a current between the probes, and the meter will record the resistance of the jacket to the flow of the Chris Deziel. Nov 28,  · Use megger on high-resistance measurements?only, such as insulation measurements or to check two separate conductors on a cable. Never touch the test leads while the handle is being cranked. De-energize and discharge the circuit completely before connecting a megger.

Electrical Academia. A high voltage source is required to pass a measurable current through such resistances. Thus, the megger is essentially an ohmmeter with a sensitive deflection instrument and a high voltage source. As illustrated in figure 1 , the voltage is usually produced by a hand-cranked generator. The generated voltage may range from V to 2. At other points on the scale, the deflection is proportional to the ratio of the unknown and standard resistors.

The range of the instrument can be altered by switching different values of the standard resistor into the circuit. Battery powered Megohmmeters are also available, and these are essentially very high resistance ohmmeters.

The battery voltage is typically increased by electronic circuitry to a level of V in order to produce a measurable current through the unknown resistance. The measurement is made when the power button is pressed and hold briefly.

This action minimizes the drain current on the battery. A Megohmmeter is also used to detect insulation failure within motors and transformers.

This is achieved by inducing high voltages into the windings of these electrical components. The introduction of a large amount of voltage will result in the detection of weakened insulation; most likely will lead to motor failure or transformer short-circuiting. The voltages used in Megger insulation testing can range from 50 V to V. By inducing a high voltage into the windings of a motor or transformer, you will be able to detect if there is insulation deterioration.

If so, the current will flow out of the windings. Escaping current can possibly result in a ground fault or a short-circuiting of the motor or transformer windings. Figure 3 shows the detailed circuit diagram of Megohmmeter. They are typically mounted to each other at an angle of 90 degrees and linked to the generator in a parallel manner. The polarities are in such a way that the torque developed by these coils is in the opposite direction.

They provide protection against any damage in case of low external resistance under test. C generator or battery connection. In manually operated megger , a DC generator provides test voltage while in digital type megger , this is done by battery or voltage charger.

Permanent magnets generate a magnetizing effect in order to deflect the pointer. Note: It is important to check with the manufacturer about performing insulation testing and ratings of the electrical component before proceeding. Too much voltage can void the warranty, shorten the life, or cause damage to the motor or transformer being tested.

When testing between the windings and earth ground the result should be zero resistance. If there is some type of resistance between the windings and earth ground, the result will be a ground fault at this point and it is important to replace the unit. When testing between two separate windings the result should be close to zero. If there is some type of resistance between the two separate windings this is an indication that the insulation is breaking down at this point and is important to plan for the equipment to be replaced.

You must be logged in to post a comment. Want create site? Find Free WordPress Themes and plugins. The megohmmeter or megger is an instrument for measuring very high resistances, such as the insulation resistance of electrical cables. Did you find apk for android? You can find new Free Android Games and apps.

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