
Accu-Ohm 200
The Accu-Ohm 200 S2 is especially designed to accurately measure low
resistances from 1 micro-ohm to 300 milli-ohms. Using a microprocessor, the Accu-Ohm 200 S2 can accurately calculate and display a resistance reading at any current from 10A to 200A. The Accu-Ohm 200 S2 is
designed for testing EHV circuit-breaker contact resistance, bushing contact joints, or for any low-resistance measuring application.
The Accu-Ohm 200 S2 applies an un-filtered direct current from 10A to
200A to the resistance load being tested. Any test current setting can be
selected by using the current control dial on the front panel. The resistance reading is displayed directly in micro-ohms or milli-ohms. No calculations are required to compensate for lead resistances when using
the Accu-Ohm 200 S2.
The Accu-Ohm 200 S2 features a back-lit LCD screen (1-inch high, 16
characters by 2 lines) that is viewable in both bright sunlight and lowlight levels. The resistance reading is displayed on the screen until the
next test is initiated. The last three resistance measurements are stored
internally and can be displayed on the LCD screen. An RS-232C interface
port is also provided for diagnostic testing.
Accurately
• Reliable, inexpensive, and easy to use
• 10 to 200 Amperes DC test current
• Digital resistance readings from 1 micro-ohm to 300 milli-ohms
• Stores and can display last 3 readings
FEATURES
Ordering Information
Accu-Ohm 200 Series 2
Accu-Ohm 200 S2 with 30-ft Test Cables Part No: Accu-Ohm 200 S2
Accu-Ohm 200 S2 Shipping Case Part No: Accu-Ohm 200 Case
15-foot Test Cable Part No: Accu-Ohm 200 Cable-15ft
30-foot Test Cable Part No: Accu-Ohm 200 Cable-30ft
C-Clamp Set (2 clamps) Part No: C-Clamps
Alligator Clamp Set (2 clamps) Part No: Alligator-Clamps
Hand Spike Set (2 probes) Part No: Handspike
ACCESSORY CLAMPS and HANDSPIKE
The Accu-Ohm 200 S2 is furnished with two 30-foot test cables. Fifteenfoot test cables are also available as an option. Both cables are terminated with quick disconnect clips. Heavy-duty, welding-type, C-clamps are
available as an optional accessory. These can be used to connect the test
cable leads to a wide variety of bushing sizes, bus-bars and other conductors requiring low-resistance test contacts.
The Accu-Ohm 200 S2’s power supply is thermally protected, and the
con
tact-sensing inputs are protected against static-discharge damage.
Special-Purpose Micro-ohmmeter
2

Resistance from
Measure
Built-in Circuit Breaker
Sensing Lead
onnector
C
Current-Lead
Connector
resence Indicator
P
1 micro-ohm to 300 milli-ohms
RS-232C Interface
ack-lit LCD Screen
B
(16 characters by 2 lines)
Current Control Knob
igh Current
H
Function
ontrol Knob
C
TYPE
PHYSICAL SPECIFICATIONS
INPUT POWER
RESISTANCE READING RANGE
TEST CURRENT RANGE
DISPLAY
INTERNAL TEST RECORD STORAGE
COMPUTER INTERFACE
SAFETY
ENVIRONMENT
HUMIDITY
ALTITUDE
CABLES
OPTIONS
WARRANTY
Note: The above specifications are valid at nominal voltage and ambient temperature of +25°C (+77°F). Specifications are subject to change without notice.
SPECIFICATIONS
Portable micro-ohmmeter
16.8” W x 12.6” H x 10.6” D (42.7 cm x 32.0 cm x 26.9 cm); Weight: less than 42 lbs (19 kg)
100 – 120 Vac or 200 – 240 Vac (factory pre-set), 50/60 Hz
1 micro-ohm – 300 milli-ohms (1 micro-ohm resolution); Accuracy: ±1% reading, ± 1 count
10 Amperes – 200 Amperes, selectable
1-inch high back-lit LCD Screen (16 characters by 2 lines); viewable in bright sunlight and low-light levels
Stores and can display last 3 readings
RS-232C port (19,200 Baud) for factory calibration and diagnostics
Designed to meet IEC61010 (1995), UL61010A-1, CSA-C22.2 standards
Operating: -10˚ to 50˚ C (15˚F to +122˚ F); Storage: -30˚ C to 70˚ C (-22˚F to +158˚ F)
90% RH @ 40˚C (104˚F) non-condensing
2,000m (6,562 ft) to full safety specifications
30-foot (#1 AWG) test cables, ground cable, power cord
Transportation case, 15-foot test cables, C-clamps, Handspike
One year on parts and labor
Vanguard Instruments Company
Reliability Through Instrumentation
RVFeb10

Vanguard Instruments Company, Inc.
Vanguard Instruments Co., (VIC), was founded in 1991.
Currently, our 28,000 square-foot facility houses Administration,
Design & Engineering, and Manufacturing operations. From its
inception, VIC’s vision was, and is to develop and manufacture
innovative test equipment for use in testing substation EHV circuit
breakers and other electrical apparatus.
The first VIC product was a computerized circuit-breaker analyzer, which was a resounding success. It became the forerunner of
an entire series of circuit-breaker test equipment. Since its beginning, VIC’s product line has expanded to include microcomputer-based, precision micro-ohmmeters, single and three-phase
transformer winding turns-ratio testers, winding-resistance
meters, transformer tap-changing controllers, megaohm resistance meters, and a variety of other electrical utility maintenance support products.
VIC’s performance-oriented products are well suited for the utility industry. They are rugged, reliable, accurate, user friendly, and
most are computer controlled. Computer control, with innovative
programming, provides many automated testing functions. VIC’s
instruments eliminate tedious and time-consuming operations,
while providing fast, complex, test-result calculations. Errors are
reduced and the need to memorize long sequences of procedural steps is eliminated. Every VIC instrument is competitively
priced and is covered by a liberal warranty.
Vanguard products are available from:
Vanguard Instruments Company, Inc.
1520 S. Hellman Ave. • Ontario, California 91761 USA • P 909-923-9390 • F 909-923-9391
www.vanguard-instruments.com