RMO-TW, TD and TT Series

The Tap Changer Analyzers & Winding Ohmmeters RMO-T series are designed for winding resistance measurement of inductive objects, and for a tap changer analysis. The RMO-T instruments are based on the state of the art technology, using the most advanced switch mode technology available today. The RMO-T instruments are accurate (0,1%), powerful (up to 100 A) and lightweight (7,5 – 15,5 kg). They generate a true DC ripple free current with automatically regulated measurement and discharging circuit.

RMO-T instruments can perform a simple, quick and reliable transformer on-load tap changer condition assessment. These instruments enable measurements of a winding resistance in every tap position, current ripple values (percentage of a current drop during a tap change) and transition times during the tap changes. Problems with a connection, contacts, and selector/diverter switch operation (tap change with interruption) can be detected with these measurements.

Typical application areas of the RMO-T are high-voltage substations and industrial environments. They are intended to measure the resistance of:

• Transformer windings
• On-load tap changers
• Generators
• Electrical motors
• High-current busbar joints
• Cable splices
• Welding joints

RMO-TW series

Three-channel winding resistance measurement, one temperature measurement channel, demagnetization and tap changer verification.

RMO-TD series

RMO-TD series has all the RMO-TW features and also tap changer analysis (DRM) and OLTC motor current measurement.

RMO-TT series

RMO-TT series has all the RMO-TD features including additional temperature measurement channels.

TWA Series

The TWA series instruments are designed for six-winding resistance measurement of power and distribution transformers. As well as resistance measurement of inductive test objects. In addition, they provide powerful tap changer analysis options by using proprietary, non-intrusive DVtest features. They generate true DC ripple free current with automatically regulated measurement and discharging circuit.

The transformer measurements performed with the TWA instruments require only one single-step cable setup. Each transformer configuration has a special measurement algorithm. They are optimized for the fast stabilization of test results. The test current can be automatically passed through the HV and LV winding simultaneously in order to achieve shorter stabilization times.

The TWA40D model is a true three-phase instrument capable of simultaneously measuring winding resistances of three phases of YN configuration. As well as three-phase tap changer analysis. All TWA instrument models are capable of both single-phase and three-phase demagnetization. The DV-Win software, provides full control of all TWA functions from a PC and additional test and analysis modes and features, is included with the TWA instruments.