with fuses for each set of relaying and metering potential circuits.
Provide 20A molded-case circuit breakers for connections from control buses
to miscellaneous equipment installed in or served from the panelboard or
system cabinet. Provide plug-in strips for connection of 120 VAC supplies
to meters and recording equipment where required.
2.12.4.6
Power Supplies and Switches
Furnish a circuit breaker panelboard in the FGD system panelboard. Furnish
mechanically interlocked, main circuit breakers mounted in the panelboard
for switching or primary and backup power services. Furnish quantity as
required. Furnish molded-case circuit breaker for each tap from the
control bus to serve items requiring separate AC circuits. Provide one AC
alarm relay connected to each AC bus with two sets of contacts to close
after 2-second delay on loss of AC. Provide a 120-volt AC control bus and
a 120-volt utility bus. Provide 24 VAC or VDC power supplies for low
voltage indicating lights, meters, and transmitters, as required. Control
switches shall be heavy-duty oiltight momentary contact, spring return
unless otherwise specified, with normally open and normally closed contacts
of adequate quantity. Switch handle types, colors, and retaining rings
will be as required. Metal nameplates shall be used for position marking,
but plastic nameplates shall be used for identification, as specified,
unless otherwise noted.
2.12.4.7
Lights and Indicators
Indicating light size shall be nominal 15 mm 1/2 inch diameter and rating
shall be 120 volts ac. Lens shall be transparent, color to be indicated
later by the Contracting Officer, unless otherwise specified. Indicators
shall be of the high-accuracy D'Arsenvol type. Provide indicators in
groups, as required, with mounting hardware and frame. Meter movement
shall be suitable for 4-20 mA dc input signal. Scale markings and colors
shall be as required. Scales shall be illuminated.
2.12.4.8
Counters and Meters
Six-digit pulse counters to interface with 4-20 mA dc input shall be
provided, as required. Meters shall be semi-flush mounting, 70 mm 2.7
inches square. Accuracy shall be rated at plus or minus 2 percent. Meter
movement shall be 0-5 ampere AC, 0-1 milliampere DC signal. Scales shall
be as specified with overload red lines. Pushbuttons shall be heavy-duty
oiltight construction. Contacts shall be momentary, one normally open and
one normally closed, unless otherwise specified. Button type and color
shall be specified later by the Contracting Officer.
2.12.4.9
Recorders
Multipoint printing strip chart size shall be 254 mm 10 inchesnominal
width. Chart speed shall be 50 mm 2 inches per hour, nominal. Printing
period shall be 5 seconds per point or multi-speed using numbered dots or
plus signs with color selected later by the Contracting Officer. Provide
engraved legend plate and rubber legend stamp. Provide a 12 month supply
of charts and ink for each instrument. Recorders shall be designed for 120
volt AC power. Supply one complete set of manufacturer's tools and
accessories. Provide internal fluorescent illumination. Furnish input
circuitry for thermocouple, RTD, voltage and current input signals.
Provide three separately adjustable alarm points with latching relay for
wiring to the annunciator. Miniature pen strip chart size shall be 100 mm
4 inch nominal width. Chart speed shall be 25 mm one inch per hour.
SECTION 15864N
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