The Automatic Voltage Regulator (AVR) maintains a constant voltage levelduring load changes. AVR internal sensors regulate the configuration of the Open-Delta connections and automatically adjust the amount of DC current directed to the exciter field in order to maintain stable output voltage. This AVR NTA-5A-2T is applied in engine 45SPI, 45ESI, 35SPK, 60SPI, 75SPI, 125SPK3, 150SPK.