What Is The Difference Between Insulation Tester And Multimeter?
Every electrical equipment is well insulated which means that the body is not in contact with live conductors but age harsh, environmental chemical contamination and the high ambient temperature can deteriorate the performance of insulation. So it can be used as an insulation tester to detect the insulation level of every machine, cable, transformer and more. Let's understand it more deeply:
What are Insulation Testers?
The insulation testers are similar to the ohm metre. It applies a DC voltage source to de-energized equipment and measures and calculates the resistance by dividing the generated voltage. By the measured current the difference here is that the insulation tester generates a much higher voltage of 250 volts or 500 volts up to 10,000 volts to measure the resistance of insulation not to measure the resistance of a register like a multimeter which is a multimeter of 9 volts.
Multimeters are a basic instrument which is found in all electronics and electrical laboratories. These multimeters are used for the measurement of AC and DC currents. AC and DC voltages and resistances are found in various ranges. With a digit multimeter, you can measure AC and DC currents, voltages and resistances.Â
Difference Between Insulation Tester and Multimeter
An Insulation tester or Megger is a specialised instrument for measuring extremely high resistances, such as 10 megohms and above. It's typically used to check wire insulation inside items that can't be physically inspected, such as cable bundles or motors. Meggers perform a high voltage to measure very high resistances of up to 1000 megohms or more, which necessitates the use of a high voltage.
A multimeter, on the other hand, is a gadget that may be used for a variety of purposes, hence the term "multimeter." Voltages DC, volts AC, and ohms are all measured. Some can also test transistors and diodes and measure current, temperature, frequency, and capacitance.
Multimeters can measure resistance up to a maximum of 10 or 20 megohms. When measuring resistance, a multimeter uses a low voltage. Many portable multimeters are limited to detecting up to 100 megohms. The Keysight U1282A has an unusually high megohm rating of 600. Insulation resistance metres can measure in gigaohms or hundreds of gigaohms; some variants can even measure in tera-ohms.
Even though the measurement is done with a low voltage, a multimeter will not be able to measure such a high resistance (often a 9 Volts battery inside the multimeter). The multimeter circuit maintains a constant current and measures the voltage across the sensors to determine resistance.Â
To have a very high resistance measuring capacity with a current source powered by a 9 Volts battery, very small voltage variations would need to be monitored, and the multimeter ADC resolution has a limit. In addition, when it comes to wiring and systems that require a much higher operating voltage than 9V is utilised, it is critical to test at these higher voltages since the insulating resistance can change. A conventional multimeter will not detect this and will display an open circuit instead.Â
Why Use Insulation Testers Or Meggers Instead Of Multimeters?
Multimeters are used to measure the voltage, current, and resistance of a circuit, while meggers are used to evaluate the insulation resistance of a wire. Megger is a form of isolation. Volt, ampere, resistance, and continuity are all measured with a multimeter.
Insulation testers and megohmmeters both perform the same basic measurement function. It sends a high voltage signal into the object to be tested to measure very high resistance values. However, it frequently accomplishes much more. It usually has enhanced capabilities, such as advanced testing and measurement recording. Insulation resistance metres are designed for use in passive equivalent circuits.
On the ohms setting, the output voltage of a multimeter is too low. A voltage multiplier circuit or a hand-cranked generator can be used to supply these voltages to an insulation tester. Both metres work by supplying a fixed voltage to the item being tested and detecting the current flow.
In conclusion, the electrical resistance of a conductor is measured using a multimeter. Whereas a Megger measures the insulating resistance of an isolated group (two coils relative to mass), which a multimeter is unable to perform.
