[2.4.8.1
Transformer Taps
**************************************************************************
NOTE: A minimum of five coarse and five fine taps
is recommended to provide sufficient voltage
adjustment. Variacs should not be used where
subjected to corrosive or marine air atmospheres.
**************************************************************************
[Transformer taps, [5] [_____] coarse, [5] [_____] fine.]
[Variac.]
[_____].
][2.4.8.2
Automatic Controls
Provide control system capable of maintaining a preselected tank-to-water
potential, within plus or minus 0.025 volt regardless of changes in water
chemistry, temperature, or water level in the tank. [Provide separate D.C.
output circuits, means of adjustment, reference electrodes, and metering
for the tank bowl and riser pipe.] Provisions shall be made for readily
changing the range and limits of the operating potential.
]2.4.9
Output Voltage and Current Meters
Provide separate panel voltmeter and ammeter, not less than 63.5 mm 2 1/2
inch [round] [rectangular] 2 percent full scale accuracy at 30 degrees C
80 degrees F, temperature stability above and below 30 degrees C 80 degrees
F of at least 1 percent per 5 degrees C 10 degrees F. Provide toggle
switch for each meter.
2.4.10
Grounding Provisions
NFPA 70 and UL 467, including a grounding terminal in the cabinet. The
grounding conductor from the terminal to the earth grounding system shall
be solid or stranded copper not smaller than No. 6 AWG. The earth
grounding system shall consist of one or more 15.89 mm 5/8 inch diameter
copper-clad steel rods. Provide minimum 2440 mm 8 feet long ground rod.
2.4.11
Fuses
Cartridge-type fuses conforming to NEMA FU 1.
Provide suitable fuse
holders in each leg of the D.C. circuit.
2.4.12
Surge Protection
Protect silicon diodes by use of AC and DC lightning arresters or metal
oxide varistors against overvoltage surges and by current-limiting device
against overcurrent surges.
2.4.13
Efficiency
Overall efficiency of [65 percent] [90 percent] [_____] minimum when
operated at full output.
2.4.14
Rectifier Replacement/Spare Parts List
Provide identification and coverage for all parts of each component,
assembly, and accessory of the items subject to replacement in accordance
with Section 01781 OPERATION AND MAINTENANCE DATA.
SECTION 13112N
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