The mini-ATOS, is a professional multifunctional power transformer and substation diagnostic system. This compact and intelligent instrument can perform many routine and advanced tests such as Winding Resistance (WR), Dynamic Resistance Measurement (DRM), Turns Ratio (TR), Frequency Response of Stray Losses (FRSL), Magnetic Balance, and other diagnostic parameters. With the built-in fully automatic multiplexer, only a one-time connection is required for nearly all functions, which saves a considerable amount of time. The portable, rugged case is perfect for use anywhere onsite or in a laboratory. It is specially designed for fast and easy measurements with the well-known high precision and quality of all Raytech instruments.