HIGH-SPEED BALANCING
The high-speed balancing of the generator rotor is normally done at 120 percent of the operating speed. It maximizes the dynamic stability and provides a comprehensive evaluation of the suitability of the rotor to return to service. The quality of the refurbishment work
done on the rotor can be fully assessed. This reduces the chance of a costly forced outage. This work is normally done at a high-speed balancing facility.
The high-speed balance will eliminate the requirement of “trim” balancing on site, which is a process that can be very time-consuming (more than 14 days in some cases). This is due to the work required to disassemble and reassemble the generator to gain access to the rotor. It is recommended to perform a high-speed balance when new coils are used in rewinding the rotor. However, if the rewind was done using the same coils, the high-speed balance may not be required.