When energy-saving is enabled, the motor acceleration/deceleration operates with full voltage. 
During constant speed operation, it automatically calculates the best voltage value according to 
the load power. This function is not suitable for fluctuating loads or loads which are nearly full 
during operation. 
 When the output frequency is constant (that is, constant operation), the output voltage 
decreases automatically as the load decreases. Therefore, the drive operates with minimum 
multiplication of voltage and current (electric power) to reach the energy-saving.
 The rated voltage of a 220V motor is usually 200 V
AC
, 60 Hz / 50 Hz, and the input voltage of the 
AC motor drive may vary from 180–264 V
AC
, 50 Hz / 60 Hz. Therefore, when the AC motor drive 
is used without the AVR function, the output voltage is the same as the input voltage. When the 
motor runs at the voltage exceeding 12–20% of the rated voltage, it causes higher temperatures, 
damaged insulation, and unstable torque output, which result in losses due to shorter motor 
lifetime. 
 The AVR function automatically regulates the output voltage of the AC motor drive to the motor’s 
rated voltage when the input voltage exceeds the motor’s rated voltage. For example, if the V/F 
curve is set at 200 V
AC
, 50 Hz and the input voltage is at 200–264 V
AC
, then the drive