What Are the Moisture-proof Methods for Generator Sets

The generator manufacturer will help you find ways to avoid dampness in a humid climate.

1. Load monotonic method

Assuming that the surface is only moist, monotonicity can be achieved through the load monotonicity method. When monotonous, the generator set can operate at 50% of the rated current load. Then add 65%, 85%, and 100% of the rated current. The load for each stage is 4 to 5 hours. During the monotonic process, the insulation resistance of each winding should be detected on time. After the insulation resistance value meets the requirements, it can be interrupted monotonically and generally tested on the generator set.

2. Cold operation method

When the AVR power cord is disconnected, the generator set that has been placed in a dusty or humid environment for a long time can be left idle for about 10 minutes. This may be enough to monotonize the surface of the winding and increase the insulation resistance value to greater than 1 megohm to generate electricity. The device can resume normal operation.

3. Hot air method

Remove all covers of the generator set in order to exhaust moist air. Use a hair dryer to blow in from the air inlet of the generator set. Please note that the heat source and winding should be maintained at least 300mm to avoid overheating and insulation damage, and to control the surface temperature of the winding. The surface temperature of the winding shall not exceed 85 °C, and the inlet temperature shall not exceed 90 °C. Continuous air blowing shall be conducted every half hour and the insulation resistance value shall be recorded. When the value is greater than the specified value, the monotonic process ends. Remove the hair dryer, cover all covers, and then try again.

4. Short circuit current monotonic method

First, carry out the safety work of the electromechanical equipment of the unit to ensure the job security of the generator set. The output end of the generator set is short-circuited through a short-circuit strip, and the short-circuit strip used should be able to accept the rated current of diesel generating set. Disconnect the AVR and switch to an external 0-24V DC power supply, schedule the DC power supply voltage to ensure that the stator current per phase is 50-70% of the rated current. Stop every 30 minutes, disconnect the external excitation power supply, check and record the insulation resistance value. Assuming that 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 debugged again. The generator set can operate at rated speed, but the speed should be kept stable to avoid temperature instability.