Testing for low resistance is made possible with a digital low resistance ohmmeter (DLRO), or ductor. A DLRO test / ductor test produces complex measurements that are key when judging electrical equipment for performance and quality of life. ATEC carries DLRO from reputable, trustworthy brands like AEMC, Biddle, Megger, and more.
What is a DLRO (Digital Low Resistance Ohmmeter)?
Digital low resistance ohmmeters, known as DLRO or ductors, measure the contact resistance of a variety of facility electrical systems, like switch and circuit breakers, aircraft frame bonds, rail and pipeline bonds, and more.
Measuring low resistance of these electrical systems is crucial to identifying which resistance elements have accelerated to speeds that are beyond the accepted values. If certain elements of an electrical device or piece of equipment move too quickly, the flow of the device is interrupted, which will alter the amount of current being drawn and cause a circuit to short. A ductor test will reveal if there is a low resistance measurement present, which typically falls below 1.000 ohm.
Benefits of DLRO Testing
Low resistance measurements performed by a DLRO are necessary to prevent long-term damage and energy waste.
With every electrical device, long-term degradation will impede or fully prevent proper usage. Factors like the working environment, climate, or even regular usage can damage electrical opponents.
Unexpected resistance is one of the clearest signs of degradation or damage. The increased resistance can prevent the flow of current and cause the device to overheat and fail. When troubleshooting a malfunctioning electrical device, you may test for resistance with a tool like a standard multimeter. The results could show no issue with the resistance, reading at 0 ohms. Although, a DLRO test may reveal a resistance measured within the milliohms. Able to test currents from 0.5 mA to 600 A, the ductor can find harmful resistance that's undetectable by other equipment.
Not just saving time and money on device failure, using a Digital Low Resistance Ohmmeter can reduce energy costs. The unexpected resistance may call for greater energy used by the device, as it draws more energy that isn't even being used.
How to Conduct a DLRO Test / Ductor Test
Testing with a Digital Low Resistance Ohmmeter / ductor can be very simple, even for inexperienced users. Simply connect the DLRO test leads to the opposite ends of a Device Under Test (DUT) and begin the test with the push of a button. The only minor complications in a DLRO test can come when choosing a test method or measurement:
The easiest DLRO test uses two-wire measurements. Only involving two test leads, this method is often used for general testing. Factors like contact probe resistance can slightly affect result accuracy, so a two-wire measurement is preferred for readings above 10 ohms.
A three-wire measurement adds an extra DLRO test lead as a guard and is reserved for high-resistance testing. A three-wire test is best for measurements greater than 10 megohms.
The most accurate test method, four-wire measurements, rids all resistances which could affect results. Using two current leads and two potential leads, the four-wire test can measure resistances that are less than 10 ohms. The lack of contact resistance delivers low resistance results free of any errors.