DLRO10HD / DLRO10HDXCommon with the DLRO10 series, the DLRO10HD and DLROHDX feature output power limiting to 0.25 W so as not to heat the test piece. However, the DLRO10HD and DLROHDX have the additional benefit of combining this with two high power, high compliance ranges. Benefits include the ability to use much longer test leads, the ability to heat and, therefore, identify circuit weakness and the ability to maintain 10 A for at least a minute, which allows for improved tests on inductive loads. In addition the DLRO10HDX comes with on-board memory for up to 200 test records and the ability to download saved test results to external software.Fig 42: DLRO10HDThe two instruments are designed to operate in the harshest of conditions, surviving knocks, drops, dusty and wet conditions. They can be used in the rain, and, with the lid closed, are sealed to IP65. There is no need to worry about inadvertent connection to live supplies. High input protection shrugs it off without even blowing a fuse.The DLRO10HD and DLROHDX are powered by a rechargeable battery or from mains power, which makes them suitable to do continuous tests in a production line or repetitive use environments, even with the internal battery on charge. You never have to wait for the battery to charge.DLRO600All the features of the DLRO10 and 10X, plus additional current up to 600 A to accommodate the preferred standards to test circuit breaker contacts. Yet ease of portability has been retained, with the instrument weighing in at only 33 pounds! Measurement range from 0.1 millohm to 1 ohm facilitates all standard high current requirements. Memory stores up to 300 results while an RS232 connection enables downloading to printer or laptop. The added data manipulation capabilities enable current limitation at standard values up to 600 A, thereby eliminating the need for multiple testers to conform to a variety of standards.Fig 43: DLRO600DLRO200The DLRO200 is designed to check and measure contact resistance in high voltage circuit breakers, disconnecting switches (isolators), bus bar joints, or for any low resistance measurement. Both models accurately measure resistances ranging from 0.1 microhm to 1 ohm, at high currents. This versatile instrument can provide test currents from 10 A up to 200 A, subject to the load resistance and supply voltage. The DLRO200 delivers an unfiltered d.c. current and can drive 200 A through a total current loop resistance of 19 millohm (Supply >207 V, 11 millohm for 115 V supply).The unique design allows the weight and size of the DLRO200 to be kept to a minimum; the instrument weighs less than 14.5 kg (32 lbs). This small size plus a water / dust ingress rating of IP54 makes the test set equally at home in the workshop, on the production floor or in the field.As well as adding notes to stored results, the alphanumeric keypad allows you to set the test current directly by keying in the value required. The DLRO200 will check the continuity of the test circuit, and will quickly ramp the test current up to the desired level. The keyboard is also used to set upper and lower limits for the result and to prevent the use of excessive currents by setting an upper limit to the allowable test current.Fig 44: DLRO200MOM2The MOM2 micro-ohmmeter is designed to measure the resistance of circuit breaker contacts, bus bar joints and other high current links.MOM2 uses an ultra capacitor to generate the high output current. The ultra capacitor is able to store a huge amount of energy compared to conventional capacitors and can deliver very high current during the discharge thanks to its very low internal resistance. The MOM2 can be used anywhere to measure a low resistance value with high accuracy.With the MOM2 it is possible to make measurements according to the DualGround™ method. This means that the test object will be grounded on both sides throughout the test giving a safer, faster and easier workflow.Fig 45: MOM2MJÖLNER200 / MJÖLNER600The MJÖLNER200 and MJÖLNER600 micro-ohmmeters, like the MOM2, are designed to measure the resistance of circuit breaker contacts, bus bar joints and other high-current links, and in addition also measures contact elements in bus bars.Fig 46: MJÖLNER200With MJÖLNER200, its high current capability, up to 200 A d.c., the user avoids problems with incorrect test results due to low test current when high current devices such as circuit breakers are tested. It can also do true d.c. ripple free current tests of bus bars, circuit breakers, fuses, etc.Use the MJÖLNER600, with excessive power resources for demanding applications, for superior measurement accuracy and when 300 A continuous is required.Fig 47: MJÖLNER600The MJÖLNER200 and MJÖLNER600 also make measurements according to the DualGround™ method, the same as the MOM2, and can be used anywhere to measure a low resistance value with high accuracy. www.megger.com 3736 A guide to low resistance testing www.megger.com
