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ISO 9001 and 17025 Certified


Auto-Ohm 200 S3

DC Micro-Ohmmeter

9051-DG [Dual Ground Option]

The Auto-Ohm-200 S3 is Vanguard’s fourth 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 (16.8 lbs/ 7.6 Kg) micro-ohmmeter is designed to meet the IEEE C57.09-1999 (5.15) requirement for testing circuit breaker contact resistance.

  • Very lightweight: 16.8 lbs. (7.6 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
  • 1 to 200A programmable test current

Auto-Ohm 200 S3



Auto-Ohm 200 S3

Technical Specifications

TYPE Portable Micro-Ohmmeter
PHYSICAL SPECIFICATIONS Dimensions: 17" W x 7" H x 13" D (43.2cm x 17.8cm x 33cm)
Weight: 16.8 lbs (7.6 Kg)
INPUT POWER 100 – 240 Vac, 50/60 Hz
RESISTANCE READING RANGE 10 milliohms at 200A to 5 ohms at 1A
Typical Accuracy:
±(0.15% of reading + 0.15% FS) at test current of 10-200A
TEST CURRENT RANGE 1 Ampere to 200 Amperes (selectable in 1A steps);
Thermally protected DC power supply.
DISPLAY Back-lit LCD (128 x 64 pixels), viewable in direct sunlight and low light levels
KEYPAD Rugged, 44-key "QWERTY" membrane keypad
INTERNAL TEST RECORD STORAGE 128 test records. Each record can contain up to 64 readings.
EXTERNAL TEST RECORD STORAGE Up to 999 test records on external USB Flash drive
PC SOFTWARE  Windows XP/Vista/7 Analysis Software (included with purchase)
SAFETY Designed to meet IEC 61010 (1995), UL 61010-a, and CAS-C22.2 standards
ENVIRONMENT Operating: -10ºC to 50ºC (15ºF to +122ºF)
Storage: (-30ºC to 70ºC (-22ºF to +158ºF)
HUMIDITY (MAX) 90% RH @ 40˚ C (104˚ F) non-condensing
ALTITUDE (MAX) 2000m (6562 ft) to full safety specifications
30 ft (9.1 m), #1 AWG test cables, power cord, ground cable
Shipping case, 15 ft test cables, C-Clamp set, Hand Spike Set
One year on parts and labor
Specifications are valid at nominal voltage and ambient temperature of +25˚C (+77˚F).



Field Pictures

Auto-Ohm 200 S3 at Wuhan High Speed Train Substation