precipitator. Do not connect more than two bus sections to a single
transformer-rectifier set; connect each bus section to a single bushing and
connect each bushing to only one bus section.
2.3.3.3
Transformer Oil
Provide insulating mineral oil, PCB free, kV rated with required dielectric
rating. Sample the oil after installation and test in accordance with ASTM
D 923 and ASTM D 877. If the oil does not meet the ASTM specification, dry
and filter until it meets or exceeds the requirements.
2.3.4
Control Cabinet
Provide controls for the high voltage precipitator supply in control
cabinets and include all regulating devices. Provide control cabinets that
are completely wired, self-ventilated, free standing, and enclosed in a
grounded casing. Maintain cabinet at positive pressure using a fan powered
by a 120 volt, single-phase motor with a power output of not less than
[0.093 kW] [1/8 hp] [_____]. Filter pressurizing air with a filter that is
not less than 98.5 percent efficient for dust particles one micron or
larger. Equip control cabinet and T-R with a safety key interlock.
Construct the control cabinet in accordance with NEMA Type 12 as defined in
NEMA ICS 6. Each controller shall conform to NEMA ICS 1 and NEMA ICS 2 and
contain, but not be limited to, the following:
a.
Completely automatic solid state controller which will maintain a
preset spark rate, maximum current, and maximum voltage; silicon
controlled rectifiers driven by transistorized automatic controls
with auxiliary manual capability. Provide the reactor in
conjunction with the T-R set with a nominal impedance of 40
percent and additional taps at 50 percent and 60 percent
impedance. Provide easily accessible taps to facilitate changing
of tap position. The reactor shall hold inductance within 5
percent at 2.5 times rated current at 40 percent impedance.
b.
Full range control on both manual and automatic. Field
adjustments to the automatic control shall be maximum current,
maximum voltage, and spark rate set point.
c.
Indicators, meters, and protection.
d.
High voltage start and stop pushbuttons.
e.
Thermal line breaker with undervoltage coil and adjustable
magnetic trip.
f.
Transformer primary AC voltmeter.
g.
Transformer primary AC ammeter.
h.
Precipitator DC milliammeter.
i.
Precipitator DC voltmeter.
j.
Precipitator spark rate meter.
k.
High temperature alarm indicator for T-R oil temperatures.
l.
Auxiliary contacts for the attachment of a partable oscilloscope
SECTION 15862N
Page 27
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