Simpler Construction Operation at www.japanese-home-gardens.com

A-c generators are simpler construction operation in construction and operation than d-c generators in that it is not necessary to have a commutator in the armature circuit, since the connections between the armature coils and the external circuit are not periodically reversed as they are in d-c generators.

In many applications rotary pumps have replaced reciprocating pumps due to their smaller size, nonpulsating discharge, simpler construction operation construction, and absence of suction and discharge valves. Pressures of 2,000 psi are readily obtainable in rotary pumps and discharge rates of 35,000 gallons per minute have been reached under low pressures. In the rotary pumps described above, discharge can be varied only by changing the speed of operation of the driving motor. With alternating current motors this involves a relatively complex electronic or mechanical mechanism, hence rotary pumps have been developed which incorporate a means of discharge adjustment within the pump.

The recovery of pressure through reduction of the impeller exit velocity is accomplished more efficiently by installing a series of fixed guide vanes surrounding the impeller as in the diffuser pump. Despite the slightly greater efficiency, the volute type is more common because of lower cost and simpler construction operation construction.