The global market for high-power ac drives is expected to grow 9.1% annually for the next five years. The market, which hit $4.7 billion last year, could reach $7.4 billion in 2011, according to manufacturing and supply-chain research firm ARC Advisory Group, Dedham, Mass.

The worldwide market for low-power ac drives is expected to grow 7.9% annually over the same period. That market, which was nearly $6.0 billion in 2006, could hit $8.7 billion in 2011 .

ARC Advisory Group reports are available at www.arcweb.com/res/achi (high-power ac drives) and www.arcweb.com/res/aclo (low power).