MIL-HDBK-1004/10
e)
Sizing rectifier requirements:
dc current - 57.13 A
Anode circuit resistance - 0.508 ohms
dc voltage = IR = 57.13 x 0.508 = 29 V
A standard rectifier in this range has an output of 90 A at 42 V.
f)
Anode bed design (shore side):
Select 2- by 60-foot anodes.
For current distribution, a distributed anode system should be used.
Compare resistances of single anodes with and without backfill:
Without backfill:
R=
(P/L)K
where
R = electrolyte-to-anode resistance for a single vertical
anode.
P = 1,000-ohm cm soil resistivity
L = 5-foot anode length
K = 0.0234 factor for length to diameter (refer to para.
6.2.1.4)
R = (1000/5)0.0234
R = 4.68
With 10-inch diameter backfill in hole:
R = (P/L)K
where
R = electrolyte-to-anode resistance for a single vertical
anode
P = 1,000-ohm cm soil resistivity
L = 10-foot backfill length
K = 0.0186 factor for length to diameter (refer to para.
6.2.1.4)
R = (1,000/10)0.0186
R = 1.86 ohms
Since backfill is required to reduce the resistance below 2 ohms, backfill is
required.
g)
Minimum weight of anodes required for 15-year life (shore
side).
W=
YSI
205
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