What is your application? How big & fancy is the motor? This question came up in one of our drive applications. I couldn't get a firm maximum RPM value from our rep. He said you can overspeed them somewhat, but you lose HP. I would call the motor manufacturer to get an answer. If you are going to regularly operate in the 3000 RPM range, you should probably get a 3600 RPM motor and control that instead.
