Variable frequency motor cooling fan in the use of independent fans, mainly installed in the back of the motor, the other power supply, speed constant, and the motor speed has nothing to do, inverter motor cooling fan cooling fan delay power off control on a lot of If you want to use the above method, then put the time relay (to use the power delay type) of the coil connected in series in the inverter control circuit inside the motor, the delay disconnect contacts connected in the cooling fan circuit , When the variable frequency motor stops after the delay to turn off the cooling fan.
Frequency inverter motor cooling fan connected to the main circuit contactor switch auxiliary contacts plus delay relay when the relay should be able to achieve, the contactor closed normally open into a normally closed, normally closed into a normally open, often Open contact with the time relay coil in series, the power failure after the coil, the relay began to delay, there is a way is to use the temperature control switch to control the most simple, the price is much cheaper.
Inverter motor cooling fan directly connected in the cooling fan circuit, and then set a temperature value, when the temperature is higher than the set value, turn on the cooling motor, when the motor temperature down (stop after a period of time to temperature Down, time is also related to the weather), disconnect the cooling fan.
Frequency inverter cooling fan in the inverter control, low-frequency operation will reduce the speed, if the cold is installed on the shaft fan, then the wind is less, is not conducive to cold. So have to install another inverter motor cooling fan. However, if the frequency of running a long time, low-frequency operation time is not long, then do not have to cold indeed. In addition, if the motor with larger power, the load is relatively small, the operating frequency is not very low, then do not add fan. In short, plus the fan is cold for low frequency, if the operating temperature is not exceeded, you do not need to add.