What is megohmmeter?

Megohmmeter or Megger, as is more known, is an electric test device designed to test extremely high resistors by creating a DC (direct current) between 300 and 15,000 V. The megohmmeter creates a high voltage, low current DC hub that allows test resistors commonly occurring when winding or cable insulation tests. Megohmmeters produce this high voltage through battery internal circuits or manually controlled generator.

Testing electrical equipment, machines or installation for winding, ground or insulation with a conventional Ohmmer may not be achieved precisely due to extremely high resistance common in these applications. Resistance in these cases can range from several megohms to several million megohms and require a test voltage much higher than used by smaller ohmmeters. Megohmmeter uses DC tension ranging from 300 to 15,000 volts to accurately measure these very high resistance value. These voltages are supplied at very low current rating and are usually not dangerous to Megohmmeter users.

There are two basic types of megohmmer: a variety operated by the battery and the second that uses a hand handle or generator operated by the engine. Both variants of the Megohmmeter are able to perform accurate testing of insulation resistors on installations and devices with resistors of several terraohms (1,000,000 megohms). Megohmmeters operated by the battery use specialized internal circuits to convert low battery voltage into a higher test voltage. These tools are usually smaller and lighter than the generator versions and offer the benefits of the one -handed button, the one -handed operation and the selection of multiple operating voltages. The disadvantage of megohmmeters controlled batteries includes a short battery life and that they generally produce only a maximum of 5,000 volts.

MEGOHMMETERS generator rely on a small internal generater to create the desired high test voltage. These generators are usually operated manually using an external crank handle, but can be equipped with an internal power unit. These tools can produce voltages ranging from 300 V to 15,000 volts and require no battery replacement. One of the harmful characteristics of using this type of tool is that the operation requires two hands, which requires the use of wires on the clip or help the other person. They are usually larger and supply one test voltage.

The high voltage produced by these tools should always be kept in mind when testing an electrical device. The megohmeter test voltage should not exceed the operating voltage of the tested device too large, as this can cause irreversible damage. Although the test voltage is supplied at very low amperages, the care should always be performed with the megohmmer vent the electric shocks.