5 Jan 91
also negligible because the coating is very
= 1.32 + 0.06 + 0.00
= 1.38 ohms
This is well below the design requirement.
Calculate rectifier voltage (VREC) from equation 1-17:
VREC = (I) (RT) (120%)
= 25 amp (Current requirement from
step 11, paragraph 2-6a)
= Rectifier voltage capacity design
= 25 amp x 1.38 ohms x 1.2
= 41.4 V
commercially available 48-V, 28-amp unit is selected. To
prevent over- or under-protection as the water level
varies, automatic potential control is specified.
tank-to-water potential is maintained by the controller
through two permanent copper-copper sulfate reference
electrodes suspended beneath the anode wire circle. The
reference electrodes should have a life of at least 5
The tank-to-water potential measured by the
controller should be free of IR drop error.