Abstract: In a method of operating a tandem rolling mill, the speeds of the mill rolls are kept constant, a signal representing the mass flow of material entering the first stand is compared with a signal representing the desired mass flow of material leaving the last mill stand and the difference, if any, is used to control the load on the first stand in the sense to reduce the difference substantially to zero.

Abstract: A rolling mill having hydraulic cylinders in each housing to adjust the roll gap is provided with a control system whereby a workpiece is kept on a central path through the mill and is prevented from wandering from this path towards one of the mill housings. The system includes a pair of circuits and a connector between the circuits for averaging the load on each housing and controlling the roll gap in accordance with a certain mill stretch factor. The difference between the loads is also obtained and a signal, in accordance with a different stretch factor, is applied to the housing with the heaviest load and a signal of the same magnitude, but opposite polarity, is applied to the other housing.

Abstract: In a position transducer arrangement one or more AC operable position transducers are energised by the output of a variable amplitude oscillator. The output signals from the oscillator and the or each transducer are demodulated, or detected in turn by the same demodulator and the demodulated oscillator signal is compared with a reference signal to produce a difference signal. The difference signal is used to adjust the amplitude of the oscillator signal in the sense to reduce the difference signal to zero.