The RMO60TD can be used to measure the winding resistance of individual taps on a power transformer’s tap changer without discharging between the tests. The unit also checks whether the on-load tap changer (OLTC) performs switching without an interruption as well as analysing measurements of Ripple, Transition time, and visualizing DRM graphs. The RMO60TD can perform fully automatic demagnetization after a DC current test or when disconnecting a transformer from service. The RMO60TD has a very high ability to cancel electrostatic and electromagnetic interferences that exist in HV electric fields and is equipped with a thermal and overcurrent protection.  Automatic discharging circuit (independent of power supply) safely discharges the energy stored in the transformer windings at the end of the test in very short time with an audible and visible indication of the discharging state provided. An automatic connections check is performed at the beginning of each test, and the instrument warns the user if an open connection is detected. The companion DV-Win software enables control and observation of the test process, as well as saving and analysing the results on a PC. It provides a test report, arranged in a selectable form as an Excel spreadsheet, PDF, Word, or ASCII format. The software provides an OLTC (tap changer) condition assessment through analysis of the graphs representing dynamic resistance values during the tap changer transitions.

Features
Test currents 5 mA - 60 A DC
Measuring range 0.1 µΩ - 2 kΩ
On-load tap changer dynamic resistance measurement
Two resistance measurement channels
Rapid automatic demagnetization
Tap changer motor current monitoring channel
Built-in tap changer control unit

Applications
Power transformers
On-Load Tap Changers
Generators and electrical motors
High-current busbar joints
Cable splices