Which method is used for high resistance measurement?

Which method is used for high resistance measurement?

Two methods are used to measure high resistance, the constant voltage method and the constant current method. In the constant- voltage method, a known voltage is sourced and a picoammeter or electrometer ammeter is used to measure the resulting current.

What are the methods measurement of resistance?

Resistance can be calculated by measuring the current and voltage using Ohm’s Law. As a result, a circuit’s resistance value can be determined if the current and voltage measured values are known. Analog multimeters and digital multimeters employ the measurement principle of Ohm’s Law to measure resistance.

What are the different methods of high resistance?

The different methods used for the measurement of High resistance are as follows: Direct deflection method. Loss of charge method. Megohm bridge….Measurement of Low, Medium & High Resistance

• Kelvin’s Double bridge method.
• Potentiometer method.
• Ducter ohmmeter.

What is the significance of a Megger with respect to high resistance?

What is the significance of a megger with respect to high resistance? Explanation: Temperature protection can be provided to a bridge circuit by making use of heat sinks. Megger is used for determining very high resistances between the conducting part of a circuit and ground.

What is a Megger used to measure?

The Megger insulation tester is a small, portable instrument that gives you a direct reading of insulation resistance in ohms or megohms. For good insulation, the resistance usually reads in the megohm range.

Which instrument is used for measuring very high resistance found in cable insulation?

Megger is used to measure very high resistances, such as those found in cable insulation, between motor windings, in transformer windings. The Megger is essentially a portable ohmmeter with a built-in high voltage source.

What does a high resistance mean?

Resistance measurements are normally taken to indicate the condition of a component or a circuit. The higher the resistance, the lower the current flow. If abnormally high, one possible cause (among many) could be damaged conductors due to burning or corrosion.

What are the different methods to measure medium low and high resistances?

Low Resistance: Kelvin’s double bridge – Medium Resistance: Voltmeter Ammeter method – Substitution method – Wheatstone bridge method. High Resistance: Megger – Direct deflection method – Megohm bridge method, Loss of Charge method – Earth resistance measurement.

Which DC generator is used in Megger?

Hand driven PMDC generator is used in this test.

What do Megger readings mean?

If the megger reads a resistance under 1 (1,000 ohms) on your meter after the initial 60-second interval, the cable has failed and the cable should be removed. If the megger reads a resistance between 1-1.25 on your meter, then the cable passes. Any reading above 1.25 is considered excellent.

How does a Megger work?

Megger works on the principle of electromagnetic attraction. When a primary coil that is carrying current is placed under the vicinity of a magnetic field it experiences a force. This kind of force generates a torque that is made to deflect the pointer of the device which gives some reading.

What is high resistance tester?

A megohmmeter is an instrument that uses a high value DC voltage to measure the resistance of insulators. To measure the effectiveness of high voltage resistance, low current measurement techniques are used. A megohmmeter is also called a high resistance tester, a teraohmmeter , a megger, a high insulation tester.