DV Power RMO-H Series Handheld Micro-Ohmmeter for Fast and Safe Contact Resistance Testing
For field crews working on circuit breakers, disconnectors, busbar joints, cable splices, and other high-current connections, contact resistance testing needs to be both accurate and practical. The DV Power RMO-H Series is designed to meet that need by combining battery-powered portability, regulated true DC test current, and handheld convenience in a micro-ohmmeter platform built for non-inductive test objects. DV Power positions the RMO-H as a handheld micro-ohmmeter for accurate contact resistance measurement in substations, high-induction field environments, and factory testing.
One of the biggest advantages of the RMO-H Series is its true handheld design without sacrificing serious output current. DV Power states that the series offers user-selectable regulated test current from 1 A up to 300 A DC, depending on model. The lineup includes six models: RMO-H1, H2, and H3 for short test lead use, and RMO-H21, H22, and H23 for applications requiring test leads longer than 5 meters. The H1/H21 models provide up to 100 A, the H2/H22 up to 220 A, and the H3/H23 up to 300 A.
The distinction between the two sub-series is especially useful in the field. DV Power explains that the RMO-H1/H2/H3 models use a 1-cell 8800 mAh Li-Po battery and are intended for shorter cables, while the RMO-H21/H22/H23 models use a 2-cell 4400 mAh Li-Po battery and provide up to 8.3 V DC output for longer lead applications. This gives users a more practical way to match the instrument to their working setup instead of forcing one fixed handheld configuration into every test job.
Another important strength is the quality of the test current. DV Power specifically states that, unlike many handheld micro-ohmmeters on the market, the RMO-H instruments provide regulated and user-selectable test currents and generate an automatically regulated test ramp with stable, ripple-free true DC current during measurement. In practical terms, this matters because stable current helps improve repeatability and confidence in low-resistance measurements, especially in substation environments where interference and field conditions can challenge lesser instruments.
The RMO-H Series is also designed with safety and workflow efficiency in mind. DV Power notes that all models support testing on both-sides-grounded test objects, which improves safety in many real substation applications. The company also highlights a 1-click measurement interface, which helps speed up the test procedure and reduce operator effort. For field teams performing repeated measurements across multiple assets, that kind of simplified operation can make a real difference in daily productivity.
From a measurement standpoint, the series offers strong low-resistance performance in a compact package. DV Power lists typical accuracy of ±(0.1% rdg + 0.1% FS), 0.1 μΩ resolution, and a measuring range of 0.1 μΩ to 3000 mΩ. That gives the instrument enough precision for a broad range of contact resistance applications while still remaining easy to deploy as a field handheld. The units also weigh only about 0.95 kg / 2.1 lbs and carry an IP54 ingress protection rating, which reinforces their suitability for portable outdoor and industrial use.
Battery performance is another practical advantage. DV Power says the modern Li-Po battery design enables multiple measurements and a full day of testing without recharging. For crews working in switchyards, substations, or factory environments where carrying extra gear or stopping to recharge is inconvenient, this adds real field value beyond the core measurement specifications.
The RMO-H Series also supports digital recordkeeping and reporting. DV Power states that the instruments can store up to 10,000 measurements on an internal micro SD card, and that the free DV Win software communicates with the meters over Bluetooth. This allows users to download results, analyze them, and generate configurable test reports. For maintenance organizations that need traceability and formal documentation, this feature set helps bridge the gap between handheld field testing and structured reporting workflows.
For utilities, service providers, industrial plants, and field maintenance teams looking for a compact but capable contact resistance tester, the DV Power RMO-H Series offers a strong combination of portability, regulated high-current output, safety-focused testing, and reporting convenience. Its mix of true handheld design and up to 300 A DC test current makes it a practical solution for modern low-resistance field testing.
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