5 Jan 91
requirement and voltage requirement:
Determine the rectifier voltage (VREC) based on
the largest circuit voltage requirement of 27.5
V, because voltage requirement varies for all
three circuits. With a 120 percent safety factor
as in equation 1-17, the rectifier voltage is
27.5 x (120%) = 33 V
Total current required = 33.5 amp.
A commercially available rectifier having a rated
output of 40 V, 42 amp is selected.
control of each circuit is required.
This is best
handled by a rectifier having three separate output
Automatic potential control
To prevent over or under protection as the water level
varies, automatic potential control is specified. The
tank and riser-to-water potentials are maintained by
the controller through permanent copper-copper sulfate
reference electrodes suspended within the bowl and
riser. The reference electrodes should have a life of
at least 15 years.
The automatic controller is located in the rectifier
unit. The controller must be capable of sensing the
potential accurately and free of IR (voltage) drop
The control does this by turning off the