Abstract: A highly versatile drive arrangement that drives a linearly reciprocating piston of a water conditioning unit control valve without imparting any significant side loads on the support structure for the piston's drive rod or the associated seals. The drive arrangement includes a reversible electric motor and a motion converter, such as a lead screw arrangement, that converts the rotary motion of the electric motor's pinion or other output element to reciprocating linear motion of the piston. The reversible motor can be controlled, based on signals from a motion monitor such as an encoder, to drive the piston to any desired position within the piston upon command. This, in turn, permits the operation of the water conditioning unit to be optimized for prevailing conditions and permits the control valve's operation to be altered if, e.g., the piston becomes stuck or encounters an obstruction.

Abstract: The invention is an improvement in a sump pump drive system of the type operable in a normal or emergency mode, powered in the normal mode by a single phase AC source and having an AC-to-DC converter, a DC standby source, a sump pump and a pump drive motor. In the improved system, the drive motor is a poly-phase AC machine and the system further comprises a DC-to-AC inverter connected to the drive motor. The pump is driven using inverted DC power in both normal and emergency modes. For the first time, the system designer can select an "ideal" pump configuration (especially including speed), then an ideal motor configuration (especially including number of poles) and configure the system for a frequency to drive the pump and motor at that speed. Variants of the improved system include low rated motor terminal voltage (not more than the battery terminal voltage), a variable frequency capability for tailoring motor speed (and therefore, pumping rate) to sump water level and "soft" start and stop.