... customer demands, such as Supply voltage range, No noise, hall-free, power,etc.6. Applications: External rotor motor, centrifugal fan, ... customer demands, such as Supply voltage range, No noise, hall-free, power,etc. power,etc.GP EC drive & control Co.,Ltd ... -voltage protection,fan speed controls, fan good/bad alarm,temperature/pressure/CO2 sensor alarm and custom fan trays. our driver and controller ...