The Megger test is a method of testing making use of an insulation resistance meter that will help to verify the condition of electrical insulation. This is certainly not a new test, and has been in use for a number of years. One of the reasons that it is still such a popular option is because it is nondestructive. The test does have a limit of between 500 and 1000 volts, so it may not always be able to detect some insulation punctures. It will usually show the amount of moisture, the leakage current no the moist or dirty areas of the insulation, and winding faults and deterioration.
The best way to make sure that you have the right information and readings is to make sure that you are using the right test equipment. Fortunately, quite a bit of high quality equipment is on the market today.
The History of the Megger Test
The Megger, known also as the mega-ohm tester, has a long history. The device has been in regular use since 1903, but the history dates a bit further back to 1889. The device was quite popular by the 1920s. The term Megger is actually something of a nickname, since the device measures mega-ohms and it was a meter. It is a combination of the two words.
Through the years, the design and purpose of the test remains the same. The only thing that has really changed is the design and the level of quality for the testers themselves. Today, it’s possible to find high quality options that are easy to use and safer than the testers from yesteryear were.
Who Discovered the Megger Test?
Sydney Evershed and Ernest Vignoles started their own company in 1895 after buying the instrument section of Goolden and Trotter where they were employed. Evershed was something of an inventor and applied for several patents for different electronic devices. The hand dynamo was one and was registered with a trademark in 1903.
What is the Megger Test Used for?
The main purpose behind the Megger test is so that you will be able to test for electrical leakage in wires. They are helpful in detecting issues and leakage that other devices, such as the ohm detector, might not. This is because you will actually be running current through the device while you are testing it.
What Can Be Tested with the Megger Test?
You will find that the Megger test, or insulation resistance test, is going to be useful in a host of different situations and for different purposes. It will be possible to detect leaks on bad motors, generators, transformers, and many other devices. In addition, it is possible to test the wiring in buildings.
What are the Components You Need for the Megger Test
When performing a Megger test, you are going to need to have a number of different components. You may need to have a handheld tester for some of the small jobs, such as working on the small motors and windings, or the electrical components in a residential home. However, some of the jobs might be larger and require that you have a heavy-duty bench style tester instead. Both of the testers will come with the small cables that you can attach to the areas that you are testing.
How is a Megger Test Set Up?
One has to be very careful when setting up and performing the Megger test. If one applies too much voltage, for example, it would be possible to destroy the piece of equipment that you are testing. You will connect the output terminals to the device being tested and then turn on the device. Make sure that you are testing at the right current and make sure that you are on the maintained output mode of the tester. Select the continuous ammeter mode, and then you will be able to start gauging the results of your test. The tests are usually performed over a period of about 5 to 10 minutes at 30-second intervals, and one has to record the results each minute. Finally, you will compare the results.
What are the Possible Results of a the Megger Test?
Once you start to record your readings, you will be able to compare them with the output readings that the device should have based on the manufacturer’s specifications. If you find that the readings are incorrect, it could mean one of several things. It could mean that there is a hole somewhere in the insulation, or that the device is not running optimally.
How Does One Interpret the Results of the Megger Test
If the result shows that the resistance is under 1 on the meter, after the first 60 seconds, it likely means that the cable has an issue and needs to be removed. If it reads between 1 and 1.35 on the meter, the cable is fine. Higher readings are going to be even better. Keep recording every 30 seconds. The resistance should continue to increase with each subsequent reading. If it does not, then it means that there could be an issue and that the insulation is failing.
Who is Megger Group Limited?
The history of Megger Group Limited goes back many years.
Megger Group Limited is a well-known company that manufactures equipment for electronic testing and measuring, and they make instruments that are capable of measuring electrical power applications. The main production sites for the company are in Dover, Dallas, Taby, and Valley Forge.
When was Megger Group Limited founded?
Once a part of AVO in Dover, Megger Group Limited has been around in some incarnation for decades. In 1991, the company changed its name to AVO Megger Instruments Limited. In 2000, they changed their name to AVO International Holdings Limited, and then shortened it to AVO International Limited. Later in 2002, they became Megger Group Limited.
What Types of Products Does Megger Group Limited Offer?
You will find that Megger Group Limited actually has more than 1000 products available. Here are some of the options that you will find.
- Battery test equipment – this equipment is going to be able to help keep a better eye on batteries so that managing their lifespan is going to be easier.
- Cable fault locating equipment – the high quality cable fault locating equipment presents a faster and accurate method of locating issues within cables.
- Circuit breaker testers – testers for circuit breakers are vital if they are going to stay in good working condition. These testers will make it easy to find deviations in the breakers, so you can know whether you should keep it in service or replace it.
- Ground resistance testers – these will cover the testing of earth electrodes and the measurement of soil sensitivity.
- HiPot AC/DC test equipment – these products are going to help to check the electrical insulation quality for transformers, capacitors, power cables, motors, and more.
- Insulation resistance testers – these are available with more than 20 different models, so you will be able to choose just the right model for your needs. They will test the resistance of insulation to make sure that everything is in proper working order.
- Low resistance ohmmeters – they are very accurate and they have the ability to measure resistance as fine as 0.1 micro-ohm. These meters will work for a number of different applications, from circuit breakers to pipeline bonds.
- Overhead line testing equipment – this type of equipment will help power utilities to have the most accurate testing of their equipment. Several different models are available for different purposes.
- Power factor test equipment – these devices have the ability to measure power factor in a host of different environments, which can help to make it easy for specialists to monitor and maintain a safe environment and to keep down the costs of repair.
- Production testing equipment – these are great for the production floor and for specialists to test devices quickly, easily, and thoroughly. Different models of the devices are available to cover any type of unit that one might need to test.
- Software for asset management – while this is not a testing device it is, nonetheless, a product that is quite important for many in the field. The software is a perfect data management solution for acceptance and maintenance testing.
- Transformer test equipment – transformer repair and replacement can be costly, so it makes much more sense to invest in this testing equipment. The testers will be able to check to make sure the transformers are in good working condition.
- Watthour test equipment – this is going to be great for larger operations. Many different product options are available in this category to help with testing watthours.
- Voltage detectors – these detectors feature an easy to read LCD display that will provide AD and DC measurements from 6 to 1000 volts. They are a great addition to many toolboxes.
- Time domain reflectometers – these are able to work on just about any cable type regardless of the power rating. They are safe and can help to test the integrity of the cables with ease.
- Leak and corona detectors – the leak and corona detectors are going to be a good solution for finding partial discharges. They can help to make sure that the various components are working properly and reliably.
- Multimeters, clampmeters, and solar PV testers – this trio of equipment is quite popular because they come in many varieties to work in a host of different arenas. They are durable, as well, and can work in harsh environments with no trouble.
- Power quality testers – these testers are great for onsite work for testing, as well as recording. Some of the options in this category, such as the PA9 Wireless, are able to work with remote recording of electrical signals. Other products in this category are able to work with overhead lines, residential and commercial investigations, and more.
- Cable locators and route traces – the items can be a great help to those who need to locate cables. Some of the options are even vehicle mountable, since those who are in this field of expertise are often on the move.
- Cable height meters – these meters are going to be able to measure the height of up to six overhead meters with ease. You can be sure that they are accurate, as well.
- Structured cable (LAN) testers – the cable testers here are for cable installers and network owners. The units are able to provide high quality and high speed, which helps with installation as well as troubleshooting.
- DC test sets – these testing sets are able to help identify equipment that might be in store to have a failure. Identifying and rectifying the issues sooner rather than later can help to save money, as well as frustration.
- Multifunction copper tester – the copper tester here holds a lot of value. They have the ability to locate cable faults, and to test power, control, and communication cables. They are low voltage and safe, and useful for all different types of cable.
The above is a sampling of some of the many different products and areas of products Megger is making today. The company has many different types of devices that are going to be suitable for quite a few different applications. The name is one of the most trusted in the industry thanks to their integrity and their time in the field. Those who are in need of high quality equipment will want to see everything they offer.
Where can One Purchase Megger Products?
The company has manufacturing sites set up around the world, and they have sales centers in several locations, as well. The company has sales centers in a number of locations around the world including the United States, Canada, England, Paris, Mumbai, Bahrain, and Sydney. They have more than 1,000 different distribution points in 132 countries, so finding and purchasing their products should never be an issue. In addition, it is possible to request sales information from the company.