Automatic fan speed controller for single phase motors. The AC fan speed is controlled based on the measured temperature. When the measured temperature is lower than the temperature setpoint, the fan runs at low speed. When the selected temperature is exceeded, the fan accelerates. The higher the measured temperature, the higher the fan speed. The temperature can be set in the range of 5 – 35 °C. An optional PT500 temperature probe is required. The supply voltage is 230 VAC. The settings can be adjusted via Modbus RTU. The maximum motor current is 6 A. The fan speed is regulated by reducing the motor voltage via phase angle control - Triac technology.