Megger's NEW MTO210 transformer ohmmeter makes it easy to measure the DC resistance of all types of magnetic windings quickly, safely and accurately. The unit is also ideal for checking the operation of on-load tap changers, which are one of the most common causes of transformer problems.
- Direct 2-channel digital reading (1 µΩ to 2000 Ω)
- DC test current up to 10 A maximum
- 0.25% measurement accuracy
- Integrated demagnetization feature
- Tests operation of on-load tap-changers
- Very fast auto safety discharge circuit
The MTO210 Transformer Ohmmeter is a line-operated, field-portable instrument designed to test transformers and rotating machine windings and perform low-current resistance measurements on connections, contacts and control circuits.
The Transformer Ohmmeter is extremely useful when testing the windings and contact resistance of tap changers with “make-before-break” contacts and voltage regulators. This action will check for pitted or misaligned contacts as the instrument will give an indication if either condition occurs.
Abundant features
Timesaving features include dual channel operation, which allows the resistances of transformer primary and secondary windings to be measured simultaneously, and bi-directional current output capabilities that allow users to take advantage of any existing magnetization in the winding core to aid rapid current stabilization.
When used to check the contact resistance of make-before-break tap changes and voltage regulators, the MTO210 provides fast, dependable indication of pitted or misaligned contacts.
For added safety, circuitry is included that automatically discharges the winding or windings under test when the test is completed, if a lead is accidentally disconnected, or in the event of a power failure
Demagnetization circuitry
The MTO210 offers facilities for demagnetizing winding cores before or after resistance testing is carried out, and it can also be used as a standalone core demagnetizer. Remaining magnetization will effect frequency response measurements on the transformer and may also cause high in-rush currents when the unit is put back in service.
Regular maintenance program
The MTO210 is most effective when used in winding resistance measurements upkeep. Once a benchmark is established, subsequent test results can be compared to determine if changes are occurring in the transformers and associated control wiring, voltage regulators, etc.