| |
|
|
The Ohmstik Live Line Micro Ohmmeter is designed to be attached directly to an energized, high voltage line and read the resistance in micro-ohms of connectors, splices or switching devices carrying current. The 3 lb instrument attaches to any hot stick. The instrument 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 are displayed on the front panel LCD.
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 bus bars can be evaluated. Switches, fused disconnects, and normally open switches that have been open for long periods can be measured just after closing. All these connections can be measured quickly 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.
The Ohmstik comes in four different models. Two of these models make comparative readings of current and micro-ohm resistance. The other two models offer the ability to measure current and micro-ohm in multiple locations and save the readings for future review. The standard and wide jaw sizes of the sensor opening are available for both styles. |
|
