Effective Methods for Generator Moisture Treatment

 
Generator sets often face various environmental challenges during operation, with humidity being one of the main factors affecting their performance and reliability. Humidity not only leads to a decline in insulation performance but can also cause equipment failures and reduced efficiency. Therefore, it is crucial to address the issue of generator dampness in a timely and effective manner to ensure the normal operation of the equipment. This guide will provide a detailed introduction to various methods for dealing with generator set dampness, including visual inspection, idling drying, safe operation, blower drying, and oven drying, to help maintenance personnel take appropriate measures to restore the normal function and performance of the generator set.

Load Drying

 
Firstly, conduct a comprehensive visual inspection of the generator set. If the surface of the generator set is only damp and the internal components are relatively dry, the load drying method can be used for treatment.
 
Start the generator set: Start the generator set and operate it at 50% of the rated current load. This helps to gradually remove moisture through heating.
Gradually increase the load: After the generator set has been running stably, gradually increase the load to 65%, 85%, and 100% of the rated current. Each load stage should last for 4 to 5 hours. Gradual load increase ensures that the generator set can effectively evaporate moisture at various load levels.
Insulation resistance test: During the load drying process, regularly test the insulation resistance value of each winding. Monitor whether the insulation resistance value reaches the specified standard, and once it meets the requirements, the drying process can be stopped.

Drying via Idle Operation

 
For generator sets that have been placed in dusty and humid environments for a long time, the drying method via idle operation is effective.
 
Disconnect the AVR power line: Disconnect the power line of the automatic voltage regulator (AVR) and let the generator set idle for about 10 minutes. This can dry the surface of the windings and increase the insulation resistance value to more than 1 megaohm.
 
Check and resume operation: After confirming that the insulation resistance value meets the requirements, the generator set can return to normal operation. If the resistance value is still insufficient, it may be necessary to redo the drying or other treatments.

Drying with External Power

 
When dealing with generator dampness, effectively utilizing external power is a key step. Correct safe operation can prevent equipment damage and ensure the safety of workers. The following are specific methods for external power drying.
 
Short circuit treatment: First, short circuit the output terminals of the generator set with a short circuit bar. The short circuit bar must be able to withstand the rated current of the generator set to avoid electrical faults or safety hazards during the drying process.
 
Disconnect AVR and connect external power: Disconnect the automatic voltage regulator (AVR) and connect to an external 0-24VDC power source. Adjust the DC power voltage to keep the current of each phase of the stator within 50-70% of the rated current. This method can effectively heat the windings and promote the evaporation of moisture.
 
Regularly test insulation resistance: During the drying process, stop the generator set every 30 minutes, disconnect the external excitation power, and test and record the insulation resistance value. Ensure that the insulation resistance value reaches the specified standard before continuing the drying operation. If the resistance value is insufficient, adjust again or use other drying measures.
 
Maintain constant speed: Although the generator set should not operate at the rated speed during the drying process, it should maintain a constant speed to avoid temperature fluctuations affecting the drying effect.

Blower Drying

 
For local dampness or lighter moisture conditions, blower drying is an effective and simple treatment method. The following are detailed steps for blower drying.
 
Remove covers: Remove all covers of the generator set to help expel damp air.
 
Use a blower: Blow hot air into the generator set through the air intake. Maintain a distance of at least 300mm between the heat source and the windings to prevent overheating damage to the insulation. Control the surface temperature of the windings, and measure that the surface temperature of the windings should not exceed 85°C, and the air intake temperature should not exceed 90°C.
 
Record data: Record the insulation resistance value every half hour. Continue blowing until the insulation resistance value reaches the specified standard. After completion, remove the blower and close all covers again.

Oven Drying

 
When the generator set is severely damp or when conditions permit, using an oven for drying is an effective and comprehensive solution. Oven drying can ensure the complete removal of moisture inside the generator set. The following are the specific operating steps.
 
Dismantle the motor: Dismantle the motor as a whole (preferably separate the stator and rotor) and place it in the oven for drying. Ensure that the oven can heat evenly and has ventilation to expel moisture.
 
Set the oven: The oven should be designed as a layered structure, with the motor placed inside and the outer layer heated. The internal temperature should be maintained at 90-100°C, and ensure that there are no open flames, smoke, dust, or other flammable and corrosive gases present.
 
Baking time: It usually takes 8-18 hours of continuous baking. During the baking process, regularly measure the insulation resistance value of the motor until it reaches the specified value and stabilizes.
 
By systematically applying the above drying methods, you can effectively solve the problem of generator dampness and restore its normal operation. Each method has its specific application scenarios and operational requirements. Choosing the appropriate treatment plan can not only improve the reliability of the generator set but also extend its service life. Regular inspection and maintenance, preventing moisture intrusion, will greatly reduce the risk of equipment failure and ensure that the generator set can operate stably and efficiently under various environmental conditions. Please follow safe operation specifications to ensure the safety of the treatment process and the normal operation of the equipment.