MICRO-OHMMETER	6255
The Micro-ohmmeter Model 6255 performs low resistance measurements from 1µΩ to 2500Ω.
This easy-to-use instrument measures all inductive or non-inductive resistances with test currents
(continuous or pulsed) from 1mA to 10A. A built-in thermal switch protects the micro-ohmmeter
against overheating on the 10A range when in continuous use.
The large, easy-to-read liquid crystal display is 2.25 x 4.00”. It displays the value of resistance,
metal type, reference and ambient temperatures (if selected), alarm conditions (if selected), test
current and range and test mode (Resistive, Inductive or Auto). You can perform long measurement
campaigns (up to 60 minutes) at 10ADC. Other features include long battery life and fast load charging
(measurement stabilization in under 2 seconds).
The Model 6255 employs a four-wire Kelvin configuration, which eliminates test lead resistance for a
measurement accuracy of 0.05%. A built-in circuit filters out AC signals. The instrument provides
laboratory-level performance, offering a high precision of 0.05% with a maximum resolution of 0.1 µΩ
over seven ranges from 5mΩ to 2.5kΩ.
The Model 6255 is packaged in a sealed case. It provides a rating of IP64 with cover closed (IP53 with
cover open) and locking metal measuring terminals. The instrument is primarily a field device, but can
also be used in a shop or manufacturing process.
For operator safety and instrument protection, the instrument is fuse protected at the inputs. Two fuses,
accessible behind the front panel, protect against stored energy in inductive loads. Enhanced internal
circuitry protects against possible inductive kickback when the current is shut off.
Applications
§   Checking metallic coating resistance, especially in aeronautics
§   Ground connections and continuity measurement
§   Resistance measurements on motors and transformers
§   Contact resistance measurements on breakers and switches
§   Component measurement
§   Electrical cable resistance measurement
§   Mechanical bond tests
§   Wire to terminal connections
§   Aircraft and rail bonds
§   Many other very low resistance samples
Key Features
§   Measures from 1µΩ to 2500Ω
§   Test current selection from 1mA to 10A
§   RTD temperature measurement (optional)
§   Automatic or manual temperature compensation
§   Two programmable alarms with high or low triggering
§   Stores up to 1500 test results
§   Selectable Inductive or Resistive test modes
§   Operator safety by automatic discharge of residual charge on the equipment under test
§   Instantaneous, continuous or multiple test operation
§   Selectable metal type (copper, aluminum or other) for temperature compensation
§   Internal, rechargeable batteries conduct up to 5000 tests at 10A
§   A built-in battery pack recharger recharges the batteries by connecting to the AC line (90V/264V, 45Hz/420Hz) using a standard line cord
§   4-Wire measurement with automatic compensation of undesirable voltages and lead resistance
§   Large multi-function backlit display
§   Direct display of the measurement with its units, range, measurement mode, and (if activated) temperature compensation.
§   Measurement can be initiated from the front panel or remotely through the 9-pin communication port
§   Rugged, sealed case