How To Maintain Diesel Generator Sets With Frequent High Temperatures

The generator set often experiences high temperatures due to the following reasons, which should be investigated one by one and corresponding measures taken.

1, Improper operation of diesel generator sets

The diesel generator set did not operate according to the prescribed technical conditions, resulting in overheating of the diesel generator set. There are several situations.

(1) High stator voltage leads to increased iron loss;

(2) Excessive load current leads to increased copper loss in the stator winding;

(3) If the frequency is too low, it will slow down the speed of the cooling fan and affect the heat dissipation of the generator;

(4) The power factor is too low, which increases the excitation current of the rotor and causes the rotor to heat up.

In order to avoid the above situations, it is necessary to check whether the indications of the monitoring instruments are normal, so that the diesel generator set can operate according to the prescribed technical conditions. If the instrument indication is abnormal, relevant parameters such as stator voltage should be adjusted in a timely manner.

2, Unbalanced three-phase load current

The three-phase load current of the diesel generator set is unbalanced, and one phase winding is overloaded, resulting in overheating phenomenon; Unbalanced three-phase current will generate a negative sequence magnetic field, thereby increasing losses and causing heating of components such as magnetic pole windings and sleeves. When the difference in three-phase current exceeds 10% of the rated current, the three-phase current will become severely unbalanced. At this time, the three-phase load should be adjusted to ensure that the currents of each phase are as balanced as possible.

3, Poor ventilation

The air duct is blocked by accumulated dust, resulting in poor ventilation and difficulty in cooling the generator, leading to overheating. At this time, dust and oil stains should be removed from the air duct to make it unobstructed.

4, Cooler blockage

Excessive inlet air temperature or inlet water temperature can cause the cooler to be blocked. What should we do in this situation? Firstly, the blockage inside the cooler should be removed; Secondly, the load of diesel generator sets should be limited to reduce the inlet or inlet temperature; Finally, after confirming that the fault has been resolved, the load limit will be lifted to allow the diesel generator set to operate normally.

5, Bearing issues

(1) Excessive or insufficient addition of lubricating grease for diesel generator set bearings. Lubricating grease should be added in the prescribed amount. The usual rule is to add 1/3 to 1/2 of the bearing chamber, and the maximum amount cannot exceed 70% of the bearing chamber. If the rotational speed is low, add multi-point bearing grease; If the speed is too high, add a small amount of bearing grease.

(2) The bearings of the diesel generator set are worn. If the wear is not severe, it will cause local overheating of the bearing; If the wear is severe, it can cause friction between the stator and rotor, leading to local overheating of the stator and rotor. The bearings should be checked for noise in a timely manner. If friction is found between the stator and rotor, the bearings should be replaced or stopped for maintenance.

6, Stator core issue

The insulation of the stator core of a diesel generator set is damaged, causing a short circuit and increasing local eddy current losses in the core, leading to heating of the core. In severe cases, it can damage the stator winding. At this point, the operation should be stopped immediately for maintenance.

7, Stator winding problem

The parallel wires of the stator winding of the diesel generator set are broken, increasing the current of other wires and causing the wires to heat up. At this point, the operation should be stopped immediately and maintenance should be carried out.