Answer: Generator general electrical testing items include: preventive testing of insulation during maintenance (including measuring insulation resistance, absorption rate or polarization index, DC withstand voltage and leakage test, fixed power frequency AC withstand voltage test, measurement of); DC resistance of rotor winding; testing AC impedance and rotor power loss; tests during generator operation (no-load test, load test, temperature rise test).
The airtightness test of the generator requires a start-up, and the thermal test of the AC and DC withstand voltage before overhaul of the generator also requires a shutdown.
The goal of starting is:
1. Start-up at start-up, because before start-up, the turbine is usually cold, and the temperature in the cylinder and bearings is high. is weak, and theSteam turbine must supply steam and vacuum to the shaft seal before rotating. If the turbine is not started, once the high temperature shaft seal steam enters the shaft seal and the cylinder, it will form a hot temperature difference. at the top and cold at the bottom, causing cylinder deformation and rotor bending. Wait for equipment failure.
2. Starting after stopping is mainly to consider the impact of cylinder waste heat on the rotor and cylinder block, it is also easy to cause large temperature differences between the upper and lower cylinders, thermal. rotor bending and other defects.
3. Power plants generally stipulate that start-up must be carried out in accordance with regulations before start-up and after shutdown. Starting after stopping generally requires the cylinder temperature to reach temperature aambient temperature before startup can be stopped.
4. If the rotation motor fails or loses power, or the oil pressure of the lifting shaft is insufficient, etc., you generally need to mark the position where the rotor just stopped and rotate manually of 180 degrees every 30 minutes, so repeat until the cylinder temperature is normal. Before the last manual start, the time interval is half of the previous time interval, i.e. 15 minutes.
The process of automatically disengaging the rotating device
After the impulsing of the rotor, the rotating speed of the rotating device suddenly increases, and the rotating ratio shifts from the driving wheel to the drive wheel and is quickly pushed to the right. The swivel shell rotates counterclockwise and pushes the pull rod up.
When the upper end point of the tie rod exceeds thebalance position, the connecting rod pushes the crank to rotate counterclockwise under the push of the compression spring, pulling the pivoting shell upward until the steering wheel rotates in the predetermined meaning. Angle and lock pin automatically fall into the keyhole to lock the steering wheel.
At this time, the travel switch operates, cuts off the power to the motor, all gears stop rotating, and the rotating device returns to the disengaged state before it was put into operation. Pressing the start stop button and turning off the power supply may also cause the starting device to stop.