One of the best methods of testing the current carrying efficiency of conductor junctions is by measuring the junction resistance. Circuit breaker or relay contacts, bus bars and switchgears constantly carry high currents. If the junctions deteriorate, the current carrying efficiency may be reduced and cause several problems like welding of contacts, localized Ohmic heating and eventual component failure.
If you are looking for a good MicroOhmmeter, you might want to consider DLROs from Megger. This brand has been known for their high quality and accurate testers. Their years of experience have helped them develop tools that are trusted by many.
Some of the popular testers in their product line are the Megger DLRO200-115 Digital Low Resistance Ohmmeter and the Megger 200 Amp Micro-Ohmmeter (MOM2). Both testers can provide a maximum output of 200 Amperes per test. However, each tester has unique characteristics which make them suitable for specific applications. Below is a comparison of the two Megger MicroOhmmeters.
If you need a MicroOhmmeter that is lightweight and handy, consider getting the MOM2. This compact device can deliver a very high test current of 200 Amperes using batteries. How is this possible? The meter utilizes an ultra-capacitor that can store a large amount of current compared to ordinary capacitors. The ultra-capacitor has a low internal capacitance which allows it to deliver a very high current on discharge. This MicroOhmmeter is suitable for low resistance measurement applications that can tolerate variations in the test current. It also features a DualGround configuration for extra safety when testing. The MOM2 can measure resistance from 1 μΩ to 1000 mΩ and sets the range automatically. This can help you save time and effort during resistance measurement. Another great feature of this meter is its Bluetooth connectivity. This allows you to pair it with a computer and download the test results. The MOM2 is compliant with the IEC and IEEE standards to ensure accuracy and safety.
This MicroOhmmeter is suitable for applications that demand precise, noise-free and smooth DC test current. The DLRO200-115 has an extra filtering system that suppresses AC mains line ripple. The special filtering circuit of the DLRO200-115 helps eliminate accidental tripping of a circuit breaker’s control caused by magnetic transients. It can put out a test current 200 Amperes through a loop resistance of 11 mΩ. The output current is also variable from 10 Amperes up to 200 Amperes. The high output current allows the meter to measure resistance as low as 0.1 μΩ. It also has an internal memory where you can store 300 test results and also notes. The DLRO200-115 has an Ingress Protection 54 which makes it suitable for production, field and workshop applications. The unit weighs only 15kg which makes it easy to move around.
Knowing the differences between these two products can help you find a suitable meter that fits your requirements.
For non-critical applications like in measuring the resistance of bus bars, switchgears and terminal junctions, the MOM2 is the ideal tester. It is portable, compact and can put out a very high test current. For measuring very low contact resistance of sensitive devices like high voltage circuit breakers, the DLRO200-115 is the best tester. Its ultra-pure DC output helps reduce accidental activation of trip units.
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