For more information, contact:

Richard Beck Advanced Energy Industries, Inc. 970.407.6204 dick.beck@aei.com

Cathy Kawakami Advanced Energy Industries, Inc. 970.407.6732 cathy.kawakami@aei.com

Advanced Energy Names Convergent Technology Vice President

FORT COLLINS, Colorado (September 6, 2001)—Advanced Energy Industries, Inc. (Nasdaq: AEIS) today announced it has named Ralph Castain as vice president and general manager of its Convergent Technologies strategic business unit (SBU). Mr. Castain will be working with Ray Dils, co-vice president of the unit.

Jim Gentilcore, executive vice president and chief operating officer, said, “Our Convergent Technologies SBU addresses next generation opportunities that bring together critical process components and integrates them into a subsystem architecture to provide real-time process tool monitoring and diagnostics. We chose Mr. Castain to lead this SBU due to his solid track record in leading and implementing new corporate initiatives, and his strong technical background. The depth of Mr. Castain’s experience and tenure in the field of technology will be an important asset to the organization as a whole.”

Mr. Castain spent six years at Eaton Corporation where he was instrumental in the company’s e-business initiative. Prior to joining Eaton, he worked at Harris Semiconductor, Jet Propulsion Laboratory, and Los Alamos National Laboratory in design engineering and as a chief scientist. Mr. Castain has an undergraduate degree in physics, masters degrees in physics and electrical engineering, as well as a doctorate in physics.

About Advanced Energy
Advanced Energy is a global leader in the development, marketing, and support of technology solutions that are central in the manufacture of semiconductors, data storage products, and flat panel displays. Original equipment manufacturers (OEMs) and end-users around the world depend on AE products when plasma-based technology plays a vital role in their manufacturing process. AE offers a comprehensive suite of products for vacuum process systems, including power management, temperature sensing, dynamic temperature control, gas delivery management, process monitoring and machine control tools, ion-beam sources, and plasma abatement technologies. AE technology solutions are sold and supported globally by direct offices, representatives, and distributors. Founded in 1981, AE is a publicly held company traded on the Nasdaq National Market under the symbol AEIS. AE’s URL is www.advanced-energy.com

Safe Harbor Statement
This press release contains certain forward-looking statements subject to known and unknown risks and uncertainties that could cause actual results to differ materially from those expressed or implied by such statements. Such risks and uncertainties include, but are not limited to: the volatility and cyclicality of the semiconductor and semiconductor capital equipment industries, fluctuations in quarterly and annual revenues and operating results, Advanced Energy’s ongoing ability to develop new products in a highly competitive industry characterized by increasingly rapid technological changes, and other risks described in Advanced Energy’s Form 10-K, Forms 10-Q and other reports and statements, as filed with the Securities and Exchange Commission. These reports and statements are available on the SEC’s website at www.sec.gov. Copies may also be obtained by contacting Advanced Energy’s investor relations at 970-407-6732. The company assumes no obligation to update the information in this press release.