Winding Resistance & Turns Ratio Meter – Overview

This instrument can precisely and safely determine winding resistances, transformation ratios, and phase angles of distribution transformers up to 100MVA and more. Further, it is possible to automatically move the tap charger of the H.V. winding to the next tap and perform cool-down measurements in temperature rise tests to calculate the resistance in the case of a load disconnection. The Winding Resistance & Turns Ratio Meter MRC7300A can be used by transformer manufacturers, electricity supply companies, and repair companies which carry out on-site measurements under unfavourable conditions. Resistance values ranging from 50 µΩ to 500 µΩ can easily be measured and logged with the internal measuring current of a maximum of 15 A up to a power of Approx. 100 MVA and more. To allow a comparison of the measured values to previous measurements, a conversion of the temperature of the test object is provided to compare measurements of a detached transformer carried out in winter and measurements carried out in other seasons. The measuring range is between 0.9:1 and 2500:1 in the case of the transformation ratio; the resolution of the angle measurement is 0.1 degrees. The logging of all measured values is performed by a separate printer, computer, or via the internal memory. The magnetic loading of the transformer is performed quickly to a relatively high rating voltage (50V). The unloading of the core is very safe, as the energy is dissipated in the MRC7300A by a ballast resistor and varistors except for a negligible rest.

Winding Resistance and Turns Ratio Meter- Features

• Automatic measurement without any manual interaction
• Resistance measurement with high accuracy and up to 15 A current
• Ratio measurement including phase angle and magnetizing current
• Dual measuring method for faster measurements
• Automatic vector group detection
• Tap changer control measures all transformers tap automatically
• Heat-up measurement including an algorithm for resistance at t=0
• Temperature measurement and compensation to 20 °C for Cu or AI
• USB port to get full external control over the instrument
• Thermo printer

Datasheet