Diesel generators will inevitably encounter bad weather when used outdoors, and improper handling is easy to get damp, especially the motor of the diesel generator set is damp, which has a great impact on the life and work of the generator set. After the diesel generator is damp, it must be dried in time. The solution is as follows.
First, hot air method
Remove all cover plates of the generator set to facilitate the escape of humid air. Use an electric hair dryer to blow air inward from the air inlet of the generator set. Note that at least 300mm should be kept between the heating source and the winding to avoid overheating and insulation damage. Control the winding surface temperature, using a thermometer to measure the winding surface shall not exceed 85 ° C, the inlet shall not exceed 90 ° C. Keep blowing 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 run again.
Second, oven (oven) baking method
In the place where conditions exist, the motor as a whole (it is best to put the stator and turn it apart) into the oven (oven) to gradually heat up and bake. The oven (oven) should be able to ventilate. In order to take away the moisture in the motor, and it is best to be sandwich, the inner layer of the motor, heating in the outer layer. The temperature of the inner layer is maintained at 90 to 100°C, and there is no open flame, smoke, and other flammable and corrosive gases. It is generally required to bake continuously for 8 ~ 18h, and 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, cold operation method
A generator set left in a dusty, humid environment for a long time can run idling for about 10 minutes with the AVR power wire disconnected, which may be enough to dry the winding surface and increase the insulation resistance value to more than 1 megohm, allowing the generator set to return to normal operation.
Fourth, short circuit current drying method
First of all, the mechanical and electrical safety operation of the unit is carried out to ensure the safety of operation on the generator set. The output end of the generator set is shorted through the short circuit sheet, and the short circuit sheet used should be able to withstand the rated current of the generator set. Switch the AVR to external 0 ~ 24V DC power supply, adjust the DC power supply voltage, so that the stator current per phase is 50-70% of the rated current, stop every 30 minutes, disconnect the external excitation power supply, test 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 re-connected for trial operation. The generator set can not run at the rated speed, but the speed should be kept constant to avoid temperature instability.
5. Load drying method
If only the surface is wet, it can be dried with load drying method. When dry, the generator set can first run with 50% rated current load. Then the value of 65%, 85%, 100% is increased to the rated current, each load runs for 4 to 5 hours, and the insulation resistance of each winding should be regularly detected during the drying process. After the insulation resistance value meets the requirements, the drying can be stopped, and the generator set is in normal trial operation.
Post time: Jul-18-2023