Abstract: An electrochemical cell has an annular flow passage for electrolyte solution. The cell is designed such that, in an intermediate zone, the passage is of constant cross-section (to achieve high electrolytic activity) and, in end zones, the passage progressively increases in cross-section to a maximum value (to lower the current density in regions in which unwanted deposition of salts may preferentially occur). The cross-sectional shape of the passage along its length also assists in reducing turbulence in the flow thereby reducing the rate of deposition of salts. Owing to the low rate of deposition, it is possible to maintain the electrodes relatively clean by current reversal at relatively infrequent intervals. That enables the cell to be used for longer periods between cleaning operations.

Abstract: The present invention concerns electrical control circuits which are particularly applicable to use and controlling the starting of electric motors. The invention thus provides a sensing and switching circuit capable of automatically to bring into and out of operation the start winding of an electric motor at appropriate motor speeds. Appropriate means sense a voltage or current level and a trigger response to the sensed value to supply firing pulses to the gate of a triac. The trigger element is preferably an M.O.S. integrated circuit multivibrator.