2.6.2.3
Voltage Drop
Voltage drop through the filter at operation frequency shall not exceed 2
percent of the rated line voltage when the filter is fully loaded with a
resistive load (unity power factor). Voltage drop measurements shall be in
accordance with paragraph Voltage Drop Measurements.
2.6.2.4
Input Elements
Filters shall be provided with inductive inputs. If inductive input is
used an ESA is required to protect the filter. The inductor shall ensure
firing potential for the preceding ESA and shall limit the current through
the filter capacitor. The input inductor shall be designed to withstand at
least a 10,000-volt transient.
2.6.2.5
Drainage of Stored Charge
Filters shall be provided with bleeder resistors to drain the stored charge
from the capacitors when power is shut off. Drainage of stored charge
shall be in accordance with NFPA 70.
2.6.2.6
Insertion Loss
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NOTE: Use 100 dB insertion loss at 14 kHz to 10 GHz
for applications such as secure communications
installations. For other applications, insert
appropriate insertion loss and frequency range for
the specific product. Consult filter manufacturer
for detailed requirements. Also consult the
manufacturer when leakage current is important, such
as in life safety areas. There is a tradeoff
between leakage current and insertion loss when
insertion loss is measured according to MIL-STD-220
because of the test connection and the
line-to-ground capacitance. Harmonic loading of EM
filters will require alterations to the electrical
system design to protect the filters from damage.
Large individual loads, such as adjustable speed
drive and uninterruptible power supplies, should
have shielded isolation transformers on their input
line side. Multiple small individual loads, such as
computers, should have EM filters derated or
shielded isolation transformers between filter
output and the harmonic generating loads. EM
filters should be derated by 50 percent when serving
loads with substantial harmonic components. If a
facility is formally required to fully comply with
MIL-STD-188-125, filter and ESA characteristics
should meet the standard's requirements as applied
to the facility. The facility's electrical system
should be designed to meet the requirements of
MIL-STD-188-125 with commercially available filters
and ESA. The commercial electrical power feeder
should be arranged in a manner that will meet
MIL-STD-188-125 requirements. Voice and data lines
should be converted to fiber optics prior to
penetration of the EM shield. The requirements of
SECTION 13095A
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