Fan coil motor overheating fault diagnosis and elimination method

- Jan 06, 2020-

The fan coil motor is hot during operation, and the fault can be diagnosed and eliminated according to the following methods.

(1) The air duct is blocked by dust accumulation and poor ventilation, which makes it difficult for the generator to dissipate heat. The dust and grease on the air duct should be removed to make the air duct unobstructed.

(2) The motor does not operate according to the specified technical conditions, such as the stator voltage is too high, the iron loss increases; the load current is too large, the stator winding copper loss increases; the frequency is too low, which makes the cooling fan speed slower and affects the heat dissipation of the generator ; The power factor is too low, which increases the rotor excitation current and causes the rotor to heat up. Check that the indication of the monitoring instrument is normal. If it is abnormal, necessary adjustments and treatments shall be carried out to make the generator run according to the specified technical conditions.

(3) If too much or too little grease is added to the bearing, the grease should be added in accordance with the regulations, usually 1/2 to 1/3 of the bearing chamber (the lower limit for the low speed and the lower limit for the high speed), and should not exceed 70% of the bearing room is appropriate.

(4) The three-phase load current of the motor is unbalanced, and the overloaded one-phase winding will overheat; if the difference between the three-phase currents exceeds 10% of the rated current, it is a serious phase current imbalance, and the three-phase current imbalance will produce a negative Sequential magnetic field, thereby increasing losses, causing magnetic pole windings and ferrules and other components to heat up. The three-phase load should be adjusted to keep the current of each phase as balanced as possible.

(5) The parallel wires of the stator winding break, causing the current of other wires to increase and generate heat. Stop immediately for maintenance.

(6) The inlet air temperature is too high or the inlet water temperature is too high, and the cooler is blocked. Reduce the inlet air or water temperature to clear the blockage in the cooler. Before the fault is eliminated, the generator load should be limited to reduce the generator temperature.

(7) Bearing wear. If the wear is not serious, the bearing will overheat locally; if the wear is serious, it may cause the stator and rotor to rub, causing the stator and rotor avoidance to overheat. The bearings should be checked for noise. If friction between the stator and rotor is found, stop the machine immediately for maintenance or replace the bearings.

(8) The stator core insulation is damaged, causing a short circuit between the pieces, which causes the local eddy current loss of the core to increase and generate heat, and in serious cases, the stator windings are damaged. Should be stopped immediately for maintenance