Fed's Logan Says Excess Inflation Is Unacceptable; Clear That Fed Needs At Least Two More Quarter-Percentage-Point Rate Increases; Says It May Be Possible To Raise Interest Rates More Rapidly This Winter Than Us Central Bank Has Moved So Far; Important To 'Promptly' Achieve Balance In Outlook, Risks For Inflation And Employment; Adjusting Policy Gradually Can Reduce Risk That Economic Activity Deteriorates More Sharply Than Necessary