Megger BT51

• High test current
• Four terminal measurement
• Two measuring ranges (2000 mΩ. and 20,00 mΩ.)and maximum resolution of 0,01 mΩ.
• Protected against inadvertent connection to the mains supply

The BT51 Low Resistance Ohmmeter makes measurements by passing a current through the conductor under test and also monitoring the voltage across it. The test current is limited by a simple current limiting circuit and is measured by monitoring the voltage across a resistor. The test current is maintained at a nominal 2 A, and as the measurement is ratiometric, the reading is unaffected by any current variations.

An ideal product for testing integrity of various types of electronic equipment and evaluating general insulation resistance levels, the BT51 is designed for use out in the field and quickly evaluates conductors by passing a current through it and monitoring voltage levels. Current used is constantly maintained at a nominal value of 2A (radiometric), ensuring that the reading taken is not affected by current variation. Measurements are also carried out using four-wire connectors, ensuring that test lead resistance is eradicated and doesn't affect the accuracy of a reading taken.

This low resistance tester uses two ranges: 2000mΩ with resolution of 1mΩ and 20.00mΩ with resolution of 0.01mΩ. All test readings are carried out with general accuracy of ±1% of reading ± 2 digits.

To ensure safety when testing the BT51/120 has a neon lamp indicator on the front of the tester that warns against the presence of dangerous voltage even when the tester is switched off. A safe isolation mode protected by up to 240V AC by a relay circuit keeps the tester isolated from the mains supply.

Example Uses

• Commissioning and maintenance of substation equipment, where measurements can be made on such things as busbar joints, switch and circuit breaker contact resistance, fuse resistance, cold lap welded joints in aluminium earthing strip and earth bonding
   
• Maintenance of overhead transmission lines, where “hot” joints can be tested before and after their remaking or recompression
   
• Bond testing aircraft frames, including the bonding of electronic dischargers and fuel tanks
   
• Testing earth bonds in mines
   
• Rail bond testing, where a rail is used as part of a communication system or for power transmission
   
• Testing the integrity of lightning conductors
   
• Electronic equipment, where measurements can be made on such things as resistors, track resistance of printed circuit boards (quality control of plating thickness), resistance of plated-through holes on printed circuit boards, contact resistance of relays, resistance of shunts, thick film circuits, etc.