One end of the generator shaft is grounded and the other end is isolated from the bearing base. Any form of second point grounding is not permitted on the shaft!
Due to poor sealing of the coaxial turbine shaft in the generator, high-speed steam leakage along the shaft, or high-speed steam injection speed in the cylinder, the shaft is loaded. sometimes very high when a person touches it, it feels numb, but it is not easily transmitted to the excitatory side. It can also damage the oil film and the bearing on the turbine side. Usually a grounded carbon brush is connected. turbine shaft to remove it.
Excessively high temperature When the shaft tension is sufficient to break the oil film between the shaft and the bearing, discharge occurs. The discharge circuit is the generator shaft ----. --- trunnion ------ cushionednet ------ bearing support --- --Unit base Although the shaft voltage is not high, generally 4V → 6V for 50∽300MW, the loop resistance is very. low, so the shaft current generated can be very large, sometimes reaching hundreds of amps. Shaft current will cause lubrication and cooling. The quality of the oil gradually deteriorates. In severe cases, the bearings will burn out, forcing the machine to run. stop and cause accidents. Therefore, during installation and operation, measure and check the voltage between the generator set shaft and bearings.
Compare generators by measurement. Check the tension at both ends and the tension between the two. bearing and base to check and determine the quality of insulation between the generator bearing support and the base to ensure safe operation of the unit.
Generalbetween the bearing support and the base located at the excitation end of the unit. generator Install insulating pads and insulate all oil pipes, screws, screws, etc.