Megger DLRO10X 10 A Digital Low Resistance Ohmmeter

Overview

The Megger DLRO10X is a portable digital low resistance ohmmeter, often called a micro-ohmmeter, that injects up to 10 A DC to measure resistance from 0.1 μΩ to 2,000 Ω on one of seven ranges. It is the data-handling version of the DLRO10 and both belong to the Megger family that began with the original Ducter low-resistance ohmmeter, a name registered by Megger in 1908. In the field the Megger DLRO10X is used wherever a joint, contact, weld or bond must have a very low and stable resistance: circuit breaker contacts, busbar joints, cable terminations, earthing and bonding connections and the windings of motors and transformers.

Seven Star LLC supplies the Megger DLRO10X from Muscat with engineering support for customers in Oman and the GCC. Switchgear maintenance teams, power station crews and commissioning contractors rely on micro-ohm measurements to find a degraded contact before it overheats, and our team can advise on the leads and accessories needed for each job.

Measurement Principle

Resistance below one ohm cannot be measured reliably with an ordinary multimeter because lead and contact resistance dominate the reading. The Megger DLRO10X uses the four-terminal method: current is forced through the sample by two terminals while voltage is measured across two separate potential terminals, so the voltage drop of the leads is excluded and the result shows the true resistance of the item under test. The instrument checks continuity of all four connections and warns of noise before it measures.

To cancel standing voltages such as thermoelectric and galvanic emfs, the instrument applies forward and reverse current and averages the results. The average is displayed within about three seconds to a basic accuracy of 0.2 percent. The Megger DLRO10X shows the forward and reverse values as well as the average, while the DLRO10 displays the average only. For inductive loads such as motor windings, an inductive mode waits for the voltage to stabilise and then reads, and the operator decides when the result is steady.

Engineering Design of the Megger DLRO10X

The Megger DLRO10X is built into a strong, lightweight case that is IP65 with the case closed and IP54 in battery operation. At 2.6 kg with battery and 220 x 100 x 237 mm in size, it is light enough to be worn around the neck, which is useful in cramped switchgear compartments and on ladders. A large colour display shows the results, and a two-axis paddle drives a menu system for selecting the maximum test current, the measurement mode and the pass or fail limits.

The instrument runs from a rechargeable 5.2 lithium-ion pack with a typical life of about 1,300 tests at 10 A and a spare pack can be swapped in while the first pack is charged externally, with the battery state shown on the pack itself. An optional mains unit allows continuous operation for production-line testing. Duplex Connect test leads with interchangeable terminations are supplied as standard on the leadset versions, with handspikes or Kelvin clips selected as needed, and the unit is safety rated to CAT III 600 V when DH6 leads are used.

Key Features

These features explain why the Megger DLRO10X is a standard tool for contact resistance testing:

• Up to 10 A test current and seven ranges, from 1.9999 mΩ full scale with 0.1 μΩ resolution to 1,999.9 Ω.
• Automatic forward and reverse current measurement cancels standing emfs and delivers a result in under three seconds.
• Detection of continuity in both the potential and current connections prevents erroneously high readings caused by a poor contact.
• Normal, auto, continuous, inductive and unidirectional modes cover production testing and inductive loads.
• User selectable high and low limits on the DLRO10X support simple go or no-go testing.
• On-board storage of up to 700 results with notes of up to 200 characters entered on the alphanumeric keypad.
• RS232 communication for real-time or later download of results to a PC.
• Interchangeable lithium-ion battery packs with their own charge indicator allow testing to continue while another pack is charged.

Industrial Applications

Switchgear and breaker maintenance is the most common use of the Megger DLRO10X: a rise in contact resistance is an early warning of a worn or contaminated contact that will overheat under load. Utilities and industrial plants in Oman test the main contacts of medium-voltage breakers, busbar bolted joints, cable lugs and earthing connections as part of preventive maintenance, and compare the readings with previous values and with the manufacturer limits. The same instrument measures weld integrity, rail and pipe bonds, fuse resistance and winding resistance in motors and transformers.

In power, oil and gas and water facilities from Sohar to Salalah, bonding and earthing integrity is essential for safety, and a micro-ohmmeter provides a reliable proof of the connection. Seven Star LLC also supplies general-purpose measurement tools such as the Fluke 87V industrial multimeter, the Fluke 773 milliamp process clamp meter and the Fluke 8508A reference multimeter for teams that equip a complete electrical test kit around the Megger DLRO10X, and can help match leads and accessories to each task.

Technical Specifications

Values are from the Megger DLRO10 and DLRO10X datasheet; the DLRO10X is the version with colour display, limits, storage and RS232.

Request a Quote for Megger DLRO10X

Ask Seven Star LLC for a quotation on the Megger DLRO10X, including leadsets, carrying case and calibration shunts if required. Send your list of test tasks and we will recommend the leads and accessories, confirm delivery to Oman and the GCC and provide the official datasheet. Our instrumentation team in Muscat can also support enquiries for other Megger electrical test equipment, so your Megger DLRO10X arrives ready for the next maintenance outage.