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ACME, WA - SensorLink Corporation, a premier provider of hotstick instrumentation, now offers a new Live Line Micro Ohmmeter called the Ohmstik. It directly contacts an energized, high voltage line and reads the resistance in micro-ohms of any connector, splice, or switching-device carrying current. The 3.6 lb. instrument attaches to any universal hot stick and is pressed against the splice or connector in such a manner that the connection under test is between the two electrodes. In about 10 seconds, the instrument is removed from the line and the line amperage and resistance is displayed on the front panel of the instrument.
The Ohmstik calculates resistance by measuring the AC amperage in the line and the voltage drop due to the resistance of the line segment under test. This method of using the AC current in the line itself insures that realistic current distributions through the connection are being measured. No changes in the resistance measurement are seen with line currents ranging from 2 to 1400 amps. This measurement is much more direct than infrared thermography and is not subject to emmissivity, weather, current loading, background, and other infrared errors.
The Ohmstik can be used on almost any connection in a utility. Line splices can be checked after installation or after many years of service. Bolted terminals, taps, jumpers, and substation buss bars can all be evaluated. Switches, fused disconnects, and normally open switches that have been opened for long periods can be measured soon after closing. All these connections can quickly be measured after installation or surveyed after long service to ensure proper resistance.
If the correct resistance of a connection is not readily known, the Ohmstik can measure the resistance of a nearby line and then compare the resistance of connections to this line measurement. Connections are designed to have "new" resistance of 30 to 70 percent of the line they connect. The instrument can be programmed to indicate "good" or "bad" depending on this ratio and eliminate the need for linemen to know resistance values.
Applications Include:
Evaluate a line for possible upgrade in ampacity rating
Measure & Evaluate Splices on Transmission and Distribution conductors
Verify closing resistance of closed normally open switches
Check taps and jumpers for connection reliability
Indicate the aging of connections
Direct measurement of connection reliability
Predict failure to prevent future damage
Measure micro ohm resistance of a connection on a live high voltage conductor
Superior measurement compared to infrared thermography
Measures exact resistance or compare to a nearby conductor
Simple to use one button operation: sample and hold – connect and measure
Measures resistance, using AC current in the line
Measures and displays both amps and micro-ohms
SensorLink Corporation has provided high voltage sensor technology for increased system reliability and worker safety since 1985. Today, thousands of SensorLink high voltage instruments are in use worldwide in all areas of the utility power network including distribution systems, sub-stations and engineering. |
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