in order to observe both voltage and current wave forms on the
high tension electrodes.
m.
Inverse time over current relay for units rated higher than 300
milliamperes.
n.
Static regulator to limit precipitator current during automatic
control.
o.
Alarm circuit interlock which opens when transformer primary
circuit is energized.
p.
Fused control disconnect for circuit breaker undervoltage coil and
automatic control.
q.
Manual automatic control select switch.
r.
Thyristors with heat sink sized for operation without thyristor
fan.
s.
Automatic voltage control unit.
t.
Three position selector switch with indicating lights;
"LOCAL-MANUAL," "LOCAL-AUTO," and "REMOTE-AUTO" positions.
u.
Adjustable memory.
v.
Visual annunicator for each of the following conditions:
(1)
T-R overload, one each transformer-rectifier.
(2)
T-R undervoltage, one each transformer-rectifier.
(3) T-R high voltage short circuit and open circuit, one each
transformer-rectifier.
(4)
T-R open circuit, one each transformer-rectifier.
(5)
High temperature indicator for T-R oil temperatures.
2.3.4.1
Arc Suppression Within the Precipitator
Controls shall prevent or minimize sparking. The device shall suppress an
arc within 1/2 cycle and recover within two cycles to initial voltage
before arc. Recovery rate shall be adjustable.
2.3.4.2
Auxiliary Alarm
Wire the control enclosure so that an isolated contact will close and alarm
the local annunciator when any of the white indicating lights are
illuminated for any of the T-R controls specified in paragraph entitled
"Control Cabinet." Similarly provide an isolated contact to close and to
alarm the local annunciator when any T-R control is not in the
"REMOVE-AUTO" position.
2.3.4.3
Pushbutton Stations
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NOTE: Require these indicator lights if remote
SECTION 15862N
Page 28
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