Vanguard Auto-Ohm 200 S4 True DC 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) micro-ohmmeter is designed to meet the IEEE C37.09 requirement for testing circuit

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 C test current from 1A to 200A to the resistance load to

The Auto-Ohm 200 S4 controls the test currents rise and fall rates. The test current rise and fall rate can be selected from 5 seconds to 30 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.