Product Description

High current and very lightweight micro-ohmmeter

The Auto-Ohm 200 S4 is Vanguard’s fifth generation, microprocessor-based, true DC micro-ohmmeter. It is designed for testing EHV circuit-breaker contact resistances, bushing contact joints, welding joints, or for any low-resistance measuring application. This high current and very lightweight (19.8 lbs/ 8.9 Kg with printer option) micro-ohmmeter is designed to meet the IEEE C57.09-1999 (5.15) requirement for testing circuit breaker contact resistance.

The Auto-Ohm 200 S4 can accurately measure resistance values from 1 micro-ohm to 5 ohms. A 0.1 micro-ohm resolution is possible with current greater than 5A. The Auto-Ohm 200 S4 applies a selectable true DC test current from 1A to 200A to the resistance load to be tested. The Auto-Ohm 200 S4 controls the test current’s rise and fall rates. The test current rise and fall rate can be selected from 5 seconds to 10 seconds. An “Auto Test” mode is also available and can be initiated simply by applying the sense cables’ leads across the two points of interest in the current path. This feature is very convenient when measuring a sequence of several resistance values in a circuit breaker contact. The Auto-Ohm 200 S4 can also compare test results against preset limits and determine if a test passed or failed, and a “Pass” or “Fail” flag is displayed accordingly.

The Auto-Ohm 200 S4 can be configured with options like a 2.5-inch thermal printer and support for testing with both-sides-grounded

Vanguard Universal Software (VUS) version 2.15 is required to open Auto-Ohm 200 S4 test result files and create reports.

• Very lightweight: 19.8 lbs. (8.9 Kg)
• Measures circuit breaker contact resistance with safety ground on (with the Dual Ground option)
• Stores test records on-board or on external USB Flash drive
• 1A to 200A programmable test current