Drive system for high inertia load

A drive system comprising:

• a flywheel;
• a prime-mover for setting the flywheel into motion and for maintaining the motion thereof during the operation of the drive system;
• a driven device driven by the flywheel;
• a bidirectional variable speed unit coupling the flywheel to the driven device for controlling the speed thereof during the operation of the drive system such that when the driven device is accelerating it draws energy from the flywheel, and when it is decelerating it returns energy to the flywheel;
• and a control system automatically controlling the prime-mover to supply sufficient energy to the flywheel to make up or losses during the operation of the drive system said control system being an energy-responsive one and including:
• first energy measuring means for continuously measuring the energy of the flywheel;
• second energy measuring means for continuously measuring the energy of the driven device;
• summing means for summing the two measurements and for subtracting the sum from a reference value to produce a control signal corresponding to the difference between said sum and reference values;
• and control means for controlling the prime-mover in accordance with said control signal.