Zalt,
As near as I can recall, the following is a trail of the weight increases through the life of the program.
1993 – 22220 lbs.
1995 – 24100 lbs.
1998 – 25200 lbs.
2001 – 26150 lbs.
Sometime after that the weight continued to increase to 26500. The latest came with a change in the fuel system that increased the amount of usable fuel.
With respect to Brian’s concerns with generator under frequency, a circuit through the weight on wheels (WOW) switch inhibits the generator under frequency protection while in flight. However, there is no protection for generator under voltage. The generators will drop off the line at some lower rotor speed. I believe that you would have to reduce the rotor speed to approximately 80% or less.