Barred Zone Range
It is a range of operational speed which is ‘ barred’ I.e,Overridden.
This is a critical speed range which must be passed as soon as possible.
Under bridge control,the bridge control unit programme automatically increases the speed setting so that more fuel can enable the engine to cross over this speed range as fast as possible.It is specified for a given engine.
Most effective means of reducing the amplitude of torsional vibration is the sectionalizing of the shafting and interposing couplings between the sections.