DC Hipot Thumper Cable Fault Locators
There are certain features that every thumper should have. Not all do. Do not handicap your fault finding capabilities by buying ½ a thumper. Here’s what is needed:
Multiple Output Voltage Ranges
Don’t make five faults in the process of finding one. To minimize damage to the insulation and accessories, thump at the lowest possible voltage while delivering the highest possible energy, or joules. Multiple output taps, all delivering the full joule rating of the thumper, are necessary. Some thumpers have only one output voltage, requiring thumping at the maximum, too high a voltage to get all the energy out of the thumper. Some thumpers offer two taps. HVI thumpers offer three full joule output taps. 1000 joules @ 5kV is the same energy to the fault as 1000 joules @ 15kV.
Hipot/Burn Operation
There are some thumpers on the market that have no hipot/burn output, essentially half of what a thumper needs to be. A hipot output is needed to:
1. Apply voltage to a cable to verify the fault and identify the bad cable
2. Apply voltage to learn the breakdown voltage of the fault to select output voltage tap
3. Burn cable to decrease arc-over voltage to permit lower voltage, less damaging thumping
4. Hipot the cable after repair
5. Enhance the use of TDR/radar
A thumper without a variable hipot output and cable burning capability lacks the necessary tools for fast and efficient fault locating. For the same money or less, you can buy the most full featured, highest burn current thumpers on the market. Why buy a thumper that has no hipot/burn output?
Remote TDR/Radar Design
There are many advantages to having a TDR/radar unit not built-in to the thumper. Use the TDR without dragging out a 300lb thumper. More easily replace or repair the thumper or TDR without losing both. More easily upgrade the TDR or get a new one express shipped overnight if it fails. Take it into your office to download traces, or for training. Mount anywhere in the van most convenient and not be restricted to standing over the thumper to view it. Buy the thumper now and the TDR later.
Review
Don’t handicap your fault finding capabilities by buying a thumper with only half the features necessary. For the same money, you can buy a full featured thumper. When specifying, require:
1. At least two full joule output voltage settings, preferably three
2. A variable hipot output with high burn current: at least 200mA
3. A remote TDR/radar.