The WR100-12R is the more rack-mounted and more powerful version of WR50-12 which is designed more for laboratory or test van systems as a part of the Raytech ATOS system with the really high output current of 100A. It is a Winding Resistance meter system specially designed for high precision DC winding resistance measurement of high inductive windings such as very large power transformer windings. It can also be used for precisely diagnosing and for preventive maintenance. Many power transformer’s faults such as shorted turns, tap changer problems and loose connections can be detected precisely. The powerful 100A output together with smart features enable WR100-12R to charge and discharge the winding quickly. It includes also special tools such as advanced transformer core demagnetizing, temperature rise measurement and analysis (optional), and automatic temperature correction using up to 3 temperature probes. The WR100-12R can inject current to both high voltage and low voltage side using the jumper cable provided, and resistance measurement can be performed simultaneously using two separate measurement channels. Additionally, by using the Raytech MUX-R in ATOS, the same cables for winding resistance and turns ratio measurement can be used even for transformers with tertiary windings and fully automatic measurement of all three phases and all taps is possible with just one time to hook up of the test clamps.