Megger MOM2-SL5M - MOM2 Handheld High Current Micro-Ohmmeter

The Megger MOM2 Micro-Ohmmeter is designed to measure the resistance of circuit breaker contacts, bus-bar joints and other high-current links. This product is designed with safety, ease of use and versatility in mind.

The Megger MOM2 Micro-Ohmmeter 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 Megger MOM2 Micro-Ohmmeter can be used anywhere to measure a low resistance value with high accuracy. With 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. This gives a personal safe, quick and easy measurement.

The ruggedness and lightweight makes the Megger MOM2 a handheld instrument very suitable for field work, such as in substations. The unit comes with a strong rubber holster accessory which makes it extra durable. MOM2 is dimensioned to make a full day’s work of testing without recharge. It can store 190 test values and transfer test data to a PC via Bluetooth.

Low weight, ease of use and versatility has been key issues during product development. New patent pending technology has made MOM2 small and light, it weighs about 1 kg. Despite the small size and light weight the instrument can deliver a maximum current of about 220A short duration and up to 100 A for three seconds.

High current Generation Using Ultra capacitor

The MOM2 uses an ultra capacitor to generate the high-output  current. Ultra capacitors are able to store huge amounts of energy  compared to conventional capacitors. In addition, they can deliver  very high currents during discharge as a result of their very low  internal resistance.

While testing, the capacitor is discharged through the test  object. The voltage drop across and the current flow through  the test object are continuously and synchronously sampled.  The resistances calculated from the individual samples are then  averaged to obtain the final value.

Applications

MOM2 test system is designed to serve a number of applications. The most common are contact resistance measurements of low-, medium- and high-voltage breakers and also at bus-bar joints, and other high current links.

If the contact resistance is too high this will lead to power loss and temperature rise, which often leads to serious trouble. To avoid such problems, it is necessary to check the resistance at regular intervals.

The following table demonstrates how important low resistance is at high currents:

At 10 kA a contact with the resistance 0.1 mO gives a power loss of 10 kW. This power loss in one single point will definitely confer a temperature rise, which may result in overheating and possibly premature failure.

Both Sides Grounded

Within electrical power utilities, switchgear owners and service  companies, there is an increased emphasis on efficiency of  operations, maintenance and service levels. There is an increased  emphasis on health, safety, and environmental compliance.  Experience has also shown demands for shorter time periods for  testing, while the switchgear is less and less available to be taken  out of service.

Many utilities require safety grounds to remain in place during station outages, therefore, the MOM2 was designed with this field safety constraint in mind. DualGround means that the test object will be grounded on both sides throughout the test giving a safer, faster and easier workflow. Minimum time shall be spent in the substation and focus shall be on the test rather than the equipment.

4-Wire Kelvin test

The Kelvin probes (included in BD-59090) are used for a 4-wire Kelvin test. This is a way of measuring continuity resistances ensuring all contact and lead resistances are compensated for, allowing a much greater accuracy in measurements. Each Kelvin probe assembly has two probe tips: one tip is for the current generated; the other will measure the very small voltage present.

Application Examples

Circuit Breaker testing

• Test of circuit breaker contacts
• Test of the connections to the breaker

Testing of Bus-bar

• Test of Bus-bar joints
• Test of connections

Everywhere you need to test a low resistance/high current connection

• Switches
• Disconnecting devices
• Safety ground connections
• Welding points
• Fuses
• Cables

Both Sides Grounded

Within electrical power utilities, switchgear owners and service companies, there is an increased emphasis on efficiency of operations, maintenance and service levels. There is an increased emphasis on health, safety, and environmental compliance. Experience has also shown demands for shorter time periods for testing, while the switchgear is less and less available to be taken out of service.

Many utilities require safety grounds to remain in place during station outages, and the MOM2 was designed with this field safety constraint in mind. DualGround means that the test object will be grounded on both sides throughout the test giving a safer, faster and easier workflow. Minimum time is spent in the substation and focus is on the test rather than the equipment.