:: Well, of these 3 choices, ( 1 ) is not really an option-- the pump gets its power directly from the mains with no voltage regulation ( other than overvoltage protection ) . ( 2 ) is actually OK-- I expect the blowdown volume to be small, and although the liquid is somewhat hazardous ( dilute phosphoric acid with copper salts ), the discharge line will drain it directly into a waste container . ( 3 ) is possible, but will add cost and complexity.
12.
A varistor provides no equipment protection from inrush current surges ( during equipment startup ), from overcurrent ( created by a short circuit ), or from voltage sags ( also known as a power disturbances is defined by other aspects of the system design, either inside the equipment itself or externally by means such as a UPS, a voltage regulator or a surge protector with built-in overvoltage protection ( which typically consists of a voltage-sensing circuit and a relay for disconnecting the AC input when the voltage reaches a danger threshold ).
