Causes of Overheating in Diesel Generator

This article will guide you to learn the cause of overheating in a diesel generator.

The operating temperature of diesel generator has a clear allowable range. If it exceeds or falls below the allowable temperature range, the diesel generator may be damaged and even cause accidents. There are many reasons for the overheating of diesel generators.

1. The diesel generator does not operate in accordance with the prescribed technical conditions, such as too high stator voltage, increased iron loss, too large load current, increased copper loss in stator winding, too low frequency, which will slow down the speed of cooling fan and affect the heat dissipation of generator, and the power factor is too low. It will increase the rotor excitation current and then cause the rotor to heat. Users should check that the monitoring instrument’s instructions are correct. If the monitor is abnormal, must carry on the necessary adjustment and the processing, causes the generator to operate according to the stipulated technical condition.

2. The three-phase load current of the diesel generator is unbalanced, and the over-loaded one-phase winding will overheat. If the difference of the three-phase current exceeds the rated current by 10 percent, it is a serious phase current imbalance, and the three-phase current imbalance will produce a negative sequence magnetic field, thus increasing the loss. Causes the magnetic pole winding and hoop and other parts to heat. The three-phase load should be adjusted to keep the current balance as far as possible.

3. The air duct is blocked by dust and the air is not well ventilated, which makes it difficult for the diesel generator to dissipate heat.

4. If the inlet air temperature is too high or the inlet water temperature is too high, the cooler will be blocked. The inlet or inlet temperature should be lowered to remove the clogging in the cooler. Before the fault is eliminated, the generator load should be limited to reduce the generator temperature.

5. Bearings with too much or too little grease should be added as prescribed, usually 1 / 2 / 1 / 3 of the bearing chamber (upper limit of low speed and lower limit of high speed), and should not exceed 70% of the bearing room.

6. Bearing wear. If the wear is not serious, the bearing will overheat locally, and if the wear is serious, the stator and rotor may be friction, which will cause the stator and rotor to overheat. Bearings should be checked for noise, if any stator and rotor friction, should immediately stop for repair or replacement of bearings.