The CHM Series of Cable Height Meters utilize ultrasonic sound to determine the height of up to six overhead cables and wires. The instruments are designed to address specific measuring requirements on cables up to 75 feet (23 m). The CHM600 (C/N 659600) and CHM600E (C/N 659600E) are designed primarily for power cable applications, while the CHM2000 is designed for telecommunication applications.
The Cable Height Meters emit short bursts of sound which originate from the cone shaped transmitter. The microprocessor in the instruments calculates the elapsed time for the bursts of sound to be reflected from the cable back to the instruments. The result can be displayed in either feet and inches or meters. However, before the final measurement can be displayed, the air temperature must be measured because the speed of sound varies at approximately 0.2 percent per degree Celsius.
A temperature sensor, mounted at the front of the instruments, senses the actual air temperature. This information is sent to the microprocessor and incorporated into the algorithm. The distance is then displayed in meters or feet and inches depending on which was selected.
The Megger MDP series of distribution profilers provides power utilities with the most accurate and extensive information ever to precisely evaluate loading on feeders/overhead lines and to identify needed upgrades or replacement. Three different models range from a simple “current-only” version to the most advanced unit that offers a number of market-requested features. Each MDP can be easily upgraded to the next model at any time.
The Profilers are quickly installed at any point on the distribution line. An arrow on the back of the MDP unit should point towards the load. Since all units are mechanically identical and weigh less than 4.6 lbs (2.1 kg), they are easily mountable to many readily available clamp sticks for installation on live lines. Cable diameters from 0.2 in. to 1.2 in. (.5 cm to 3.0 cm) can be accommodated.