Treatment method of diesel generator set after damp

When diesel generators are used outdoors, it is inevitable that they will encounter bad weather. If improperly handled, it is easy to get wet. Especially the diesel generators are damp, which has a great impact on generator life and work. After the diesel generator is damp, it must be dried in time. The processing method is as follows.

First, the hot air method

Remove all cover plates of the generator set to facilitate the escape of humid air. Use a hair dryer to blow in from the air inlet of the generator set. Note that the heat source and the winding should be kept at least 300mm to avoid overheating and cause insulation damage. Control the surface temperature of the winding. The surface of the winding shall not exceed 85 °C with a thermometer, and the inlet shall not exceed 90 °C. Continue to blow and record the insulation resistance value every half hour. When the value is greater than the specified value, the drying process is completed. Remove the hair dryer, cover all the covers, and try again.

Second, the oven (furnace) baking method

In the place where conditions permit, put the whole motor (preferably the stator and turn it apart) into the oven (furnace) and gradually heat up the baking. The oven (furnace) should be ventilated. In order to take away the moisture in the motor, and preferably the sandwich, the inner layer discharge machine, is heated in the outer layer. The temperature of the inner layer is maintained at 90-100 ° C, and there is no open flame, soot and other flammable and corrosive gases. Generally, it is required to continuously bake for 8 to 18 hours. The insulation resistance value of the motor can be measured several times in the middle until it reaches the specified value and is stable.

Third, the cold operation method

A generator set that has been left in a dusty or humid environment for a long time can be idled for about 10 minutes while the AVR power wire is disconnected. This may be enough to dry the winding surface and raise the insulation resistance value to more than 1 megohm to generate electricity. The unit can resume normal operation.

Fourth, short circuit current drying method

First, the safe operation of the mechanical and electrical equipment of the unit is carried out to ensure the safety of operation on the generator set. The output end of the generator set is short-circuited via the short-circuit piece, and the short-circuit piece used should be able to withstand the rated current of the generator set. Disconnect the AVR and switch to the external 0~24V DC power supply to adjust the DC power supply voltage so that the current per phase of the stator is 50-70% of the rated current. Stop every 30 minutes, disconnect the external excitation power supply, and detect and record the insulation resistance value. If the insulation resistance value is greater than the specified value, the external DC power supply can be removed, and the AVR can be reconnected and re-commissioned. The generator set can be operated at rated speed, but the speed should be kept constant to avoid temperature instability.

Five, with load drying method

If the surface is only damp, it can be dried by a load drying method. When dry, the generator set can be operated with a 50% rated current load. Then increase the rated current by 65%, 85%, and 100%. The load of each stage is 4 to 5 hours. During the drying process, the insulation resistance of each winding should be checked periodically. After the insulation resistance value meets the requirements, the drying can be stopped, and the generator set is normally tested.