Maintenance and Repair of ENGGA 3-phase AC Synchronous Generator

If frequent maintenance and scheduled maintenance are carried out, it is important to detect and correct the abnormal situation, which is crucial for the safe operation of the generator and the prevention of damage. Various maintenance methods should be carried out frequently, and repairs should be determined based on the usage situation. For example, after running for 500 hours, a small inspection of the insulation resistance should be carried out, powder, oil, and mud should be cleaned, bearing oil should be replaced, and spare parts should be inspected for any abnormalities after 1000 hours. For example, whether the temperature rise is normal, whether the fan blades are deformed, and whether the screws and nuts are loose, etc. For maintenance, regular inspection arrangements should be formulated and executed according to the usage situation, record the scheduled maintenance of the well.

Normal maintenance: The ENGGA generator should not be affected by moisture. During the period of discontinuation, it is advisable to cover with a tarpaulin to avoid moisture intrusion.

Generators must be protected from metal dust, water droplets, acid alkali water vapor, or other harmful gases entering the interior of the motor during parking, installation, or operation.

The generator should maintain normal ventilation during operation. The front and rear window covers and the top covers should be kept in accurate positions, and no objects should be covered on the motor to avoid obstructing ventilation and heat dissipation. Also, do not remove the top cover from the harness to avoid affecting the ventilation and cooling of automatic voltage regulator.

Pay attention to monitoring the load of the generator. The load current should not exceed the rated current of the generator. When the power factor of the load is low, the excitation current of the generator should not exceed the rated value on the nameplate. When the three-phase load is unbalanced, the current of the maximum phase of the load should not exceed the rated current.

During the operation of the generator, the rated speed, rated voltage, and rated current of the unit must not be exceeded. During operation, if any abnormal sounds, odors, or vibrations are found, the operation should be immediately stopped. Emergency shutdown is necessary. When the unit experiences an alarm shutdown or the device trips, the cause should be promptly identified and the damage should be reported before restarting or powering on.

Check the insulation resistance of each winding and measure it with a 500 volt megohmmeter. If the insulation resistance is less than 0.4 megohms (hot state) or 5 megohms (cold state), it should be dried ten times. If the insulation resistance cannot be increased after drying, it means that the insulation has aged. The coil and insulation should be replaced and the insulation should be re cleaned.

Check that the circulation circuit of the cooling air is not obstructed. Disassemble the motor, clean the internal dust, and thoroughly blow out the inside of the motor with dry compressed air. Pay special attention to blowing out the dust between the terminals of the wiring board and on the automatic voltage regulator to prevent creepage. The surface of each coil, the interior of the fan, and each ventilation duct should also be thoroughly cleaned to ensure effective ventilation and heat dissipation.

If the automatic voltage regulator malfunctions, relevant qualified engineering and technical personnel or experts should be invited for testing or replacement with spare parts.

Inspect whether the connection part between the diesel generator set and the generator is deformed, the balance degree and the connection concentricity, and check the deformation of the fan blade.

Check whether the contact of each live part is good, tighten the screws and nuts at the wiring, and ensure that each contact can be energized properly.

Check the rectifier disk: Rotate the multimeter to the detection diode position: Connect the positive probe to the positive diode and display OI, indicating that there is no current passing through. Swap the multimeter probes so that the positive probe is connected to the opposite side, and the multimeter should read; If the diode is damaged, a short circuit reading will be given in both positive and negative directions: if one diode is damaged, all six diodes should be replaced.

Test varistor (surge suppressor).