The closed external cold water system(dry and wet combination)is mainly used in the water shortage area in northwest China

which is mainly composed of air cooling island and evaporative cooling tower.Since the air cooling island fan of some stations has been put into operation

the motor has been burned seriously

resulting in a significant decrease in heat transfer effect

which seriously affects the safe and stable operation of the unit.Through the field investigation and test of the operation condition of the air cooling island

it is found that there is a difference in the number of burnout between the frequency conversion fan and the power frequency motor. The following problems are found in the study and analysis:the frequency converter + conventional motor is used in the design of the inverter

because the frequency converter is a multimode

the pulse voltage is too large to destroy the winding insulation;The site is located in the northwest of China

the air cooling island lacks protective measures

and the heat exchanger fins are clogged seriously.Crosswind has a serious effect

and the airflow structure backfilling leads to poor heat transfer effect.Motor selection does not meet the requirements

the motor protection level is low

resulting in motor water rust. In view of the above situation

it is proposed to replace the special frequency conversion motor with long bearing life and higher protection grade

and remove the air duct and air valve of the air cooling island fan to install an anti-freezing shed.