First, in order to ensure the normal operation of the diesel generator set, there should be no accumulation of water, oil and dirt near it, and there should be no corrosive gases to avoid damaging the winding insulation of the generator. While moisture-proof and dustproof, it should be noted that the normal ventilation and cooling of the generator should not be affected. Always clean the dust and dirt in the ventilation channel to keep it unimpeded. The temperature of the cooling air should not be too low to avoid condensation on the winding and other conductive devices.
For generators that stop running for a short time for some reason, the collector ring may not be wrapped for protection, but it is necessary to pad insulating cardboard, paraffin paper or asphalt paper between the brush and the collector ring to avoid the brush forming spots on the surface of the collector ring. If the processing surface of the generator is rusted due to oil and paint falling off, the rust should be removed in time and the anti-rust paint should be applied.
Second, precautions for disassembly
The disassembly method of the generator is roughly the same as that of the asynchronous motor, but due to the large weight of the generator, care should be taken not to be hurt when disassembly. When removing the end cover, be careful not to hurt the stator coil protruding at the base of the machine; When taking out the rotor, it is necessary to pad the cardboard between the motor and the rotor to prevent damage to the iron core and winding. When tying the rotor with a steel cable, the steel cable must not touch the rotor journal, fan, electric slip and hand lead. The cable must be lined with wood or rubber.
Third, the generator drying
The newly installed synchronous generator should generally be dried before operation. If the insulation resistance meets the requirements, it can not be dried, but the load should not exceed 50% of the rated capacity within 24h from the start of operation.
When the diesel generator set in operation is stopped and repaired or stopped for more than the specified limit and the insulation resistance is lower than the specified value, it must be dried. If it is determined that the surface is wet, it can be dried by load drying method.
There are many ways to dry, and the following methods can be used on the ship:
1. Hot air method: Blow the dry and clean waste heat wind generated by the main engine into the generator to dry the fixed and rotor windings. In order to prevent shaft deformation, the rotor should be periodically turned 180 degrees. When drying, the winding surface temperature should be controlled. Measured with a thermometer, the winding surface shall not exceed 85 ° C, and the wind temperature of the intake shall not exceed 90 ° C.
2, short-circuit current drying method: the output end of the generator is shorted by the ammeter, adjust the rotor excitation current, so that the stator current per phase is 50-70% of the rated current. The generator can not run at the rated speed, but the speed should be kept constant to avoid temperature instability.
The short contact is best selected at the end of the stator lead line, or it can be shorted through the transformer and dried together with the transformer. This method can dry both the stator and the hand winding.
3, with load drying method: if the Marine generator is only wet on the surface, it can be dried with load drying method. When dry, the generator can first run with 50% rated current load. Then the value of 65%, 85%, 100% is increased to the rated current. Each stage load runs for 24h. The insulation resistance of each winding should be measured periodically during the drying process.
Precautions when drying:
Heating and drying should be carried out in clean air, and the generator should be blown clean with compressed air before drying.
If the winding is seriously damp, it is necessary to dry it with hot air method first, and then dry it with load after a certain period of time to avoid the insulation breakdown.
Post time: Nov-01-2024