A control system for the drive of stroke making devices subject to periodically occurring mechanical overloads, esp. for clearing rakes and similar machinery in sewage farms, water purifying installations, etc., has a meter for the overload and a switching circuit for the drive. On overloading, the stroke arrangement is driven at reduced speed or comes to a stop, and a driving moment greater than that exerted by the overload is maintained for a brief period after the onset of the overload, before the drive is switched off. After the cutout of the drive following overload, there is a further delay, during which time, the stroke device runs back a little before the power is switched on again. The drive is adapted to overloads which can be overcome and to thos which cannot be overcome. The safety of the various parts of the installation is improved. After switching off and a slight run back of the stroke mechanism, the blockage on the grid may have deformed itself so that when the power is reconnected, the blockage can be cleared without the necessity of a signal to the operative.
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