Most regularly alluded to as just a “megger,” the insulation testers (or Megohmmeter) is utilized to decide the state of insulation on different sorts of electrical gear like links, transformers, and switchgear.
Tests are normally led by applying an immediate current (dc) voltage to the channel under test and estimating the current that moves through insulation (called the “spillage current”) and into the non-current conveying metal pieces of gear. Sullied insulation can be controlled by watching the assimilation current – or current consumed by the insulation – over a predetermined timeframe.
The information about the insulation testers‘ resistance data might be utilized to build up a drifting example with deviations from the benchmark data license assessment of insulation. The consequences of these tests (normally communicated in Megohms) are reliant on the temperature of the protecting material and the dampness of the general condition at the trying period; hence all readings must be remedied to a base temperature, for example, 20°C.
What amount of voltage can be delivered?
Insulation analyzers arrive in an assortment of sizes and yield voltages relying upon its particular application. A handheld 1000V Megohmmeter is generally adequate for 600V class gear while bigger sets for use on high voltage mechanical assembly can yield up to 15,000V or more.
Megger Test Connections
There are three test terminals on an insulation opposition analyzer checked positive (+), negative (- ), and Guard (G). Most essential estimations use just the positive and negative terminals, for example, in situations when there is little chance of antagonistic current ways that could influence the outcome.
High Voltage Safety
Since the insulation opposition analyzer produces noteworthy DC voltages, it ought to never be associated with an empowered circuit. Hence, a few analyzers are furnished with voltage detecting capacities that will caution experts when voltage is available on a circuit. The yield of an insulation analyzer can pulverize electronic circuits, which is the reason they ought to never be associated with electronic force supplies, PLCs, VSDs, UPS frameworks, battery chargers, or other strong states gadgets.
Insulation can hold a huge voltage charge for a while after the insulation opposition test is finished. A few analyzers have a programmed release include that will release the insulation subsequent to testing; others don’t.
Most experts will ground the circuit under test after the test is finished to confirm the insulation is released. A few producers suggest the insulation obstruction analyzer stay associated with the circuit or segment under test after the test is finished for up to multiple times as long as the test was directed to guarantee safe release.
Essential Care of Test Equipment
An essential consideration for the insulation analyzer incorporates keeping the instrument clean by cleaning it occasionally with a delicate material, softly hosed with sudsy water, trailed by a spotless dry fabric. Never use liquor or solvents to clean an insulation analyzer.
In the event that furnished with battery-powered batteries, follow the producer’s suggested battery support technique. Before each utilization of the instrument outwardly investigate the test leads, goads, and crocodile clasps to affirm the insulation isn’t harmed or broken.
]Check the progression of the test leads by shorting them together and confirm that the instrument gauges an opposition short of what one ohm on the presentation.