With the market launch of KSB's new Hya®-Drive integral motor, it has now become possible to operate as many as six variable-speed pumps of equal power, plus a seventh, fixed-speed pump, without using an external switchgear.

That, in turn, does away with lots of expensive electrical cabling and space-consuming switch cabinets. The pump sets communicate with each other via two-wire cables between internal RS-485 interfaces. Whenever several of the pumps are in operation, one of them assumes the master function and controls the others. The remainder of the first six pumps serve either as standbys or for covering peak-load requirements. The seventh set is run on the mains as so-called jockey pump that is activated only in an emergency by the master pump. If the master pump cuts out, its function is transferred to one of the other pumps, which has been configured accordingly. Both pump sets are connected to the system's differential pressure sensors or flow meters.

The master pump is linked to the central control station by way of a Lon Talk interface. The optional parameterization unit includes a real-time clock enabling periodical pump changeover, holiday operation, night-time operation and programming of functions for each day of the week.

Picture: Six variable-speed high-pressure pumps operating in parallel without an external switchgear (KSB Aktiengesellschaft, Frankenthal)