Megger Tester

This vintage device is an Evershed & Vignoles Series 2 Bridge Megger Tester, a specialized electrical instrument manufactured in England during the mid-20th century. Key Features & Design • Primary Functions: It combines a standard high-voltage insulation resistance tester ("Megger") with a precision Wheatstone bridge circuit. • Cable Fault Locating: The instructions visible on the left plate detail how to perform a Varley Loop Test, a historical method used by telecommunications and utility engineers to precisely locate grounds and short circuits in buried or underwater cables. • Control Interface: The dials across the top regulate the resistance decades used to balance the bridge circuit, while the window in the middle houses a sensitive galvanometer movement to indicate when the circuit is perfectly balanced. • Power Source: It features a robust, hand-cranked internal generator on the side (visible on the left) that produces the necessary testing voltages without relying on external batteries.