Insulation Resistance Measurement Instrument

The question asks to identify the specific instrument used for measuring insulation resistance. Insulation resistance is a crucial parameter in electrical systems, indicating the quality of the electrical insulation and its ability to prevent current leakage.

Instrument Functions Explained

Let's examine the functions of the instruments listed:

• Megger: A specialized type of ohmmeter designed to measure very high electrical resistance values. It is specifically used to test the insulation resistance of electrical machinery, cables, and other equipment. It typically generates a high DC voltage for the test.
• Wattmeter: Measures electrical power (the rate at which electrical energy is transferred).
• Ammeter: Measures electrical current.
• Voltmeter: Measures electrical potential difference or voltage.

Conclusion on Insulation Testing

Based on the functions, only the Megger is designed for measuring high resistance values characteristic of insulation testing. The other instruments (Wattmeter, Ammeter, Voltmeter) measure different electrical quantities (power, current, and voltage, respectively) and are not suitable for determining insulation resistance.