Design the flywheel battery for a UPS for a large bank of computers. The computers require 6 Kw for 10 minutes. Assume the mass of the flywheel is 1 kg, the mechanical to electrical conversion efficiency is 97%, and the flywheel can be modeled as a thick walled cylinder.

1) If the flywheel spins at 40,000 rpm, find an r1 and r2 that make this combination work?

2) What are the practical ranges of r1 and r2 that will work based on sound engineering practices and accepted material properties?

Hint : 1 R/sec = 2*pi rad/sec

=>

1 R/min= 120*pi rad/min