2.3.6
Access Openings and Cover Plates
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NOTE: When installation of the filter unit inside
of the shielded enclosure is required, the power
input terminal compartment shall be RF tight instead
of the load terminal compartment; and the filters
shall be located in the load terminal compartment.
This arrangement is necessary to prevent radiated RF
energy within the shielded enclosure from inducing
RF energy in the power conductors between the
filters and the point where the conductors pass
through the shielded enclosure wall. To provide for
this arrangement, change the wording as necessary,
i.e., change the word "Load" to read "Power Input"
and change the words "Power Input" to read "Power
Output" or "Load," as appropriate.
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Provide access from front of enclosure. Access opening for load terminal
compartment shall provide clear access to filter load terminals and
standoff insulator terminals or insulated terminal blocks specified herein.
Provide power input compartment opening with clear access to filter power
input terminals and standoff insulator terminals or insulated terminal
blocks specified herein. Provide for easy removal of individual filters
from enclosure. Provide two access cover plates. One plate shall cover
the access opening to the load terminal compartment only and when secured
in place shall provide an RF tight seal with the compartment it covers.
Second access cover plate may abut or overlap cover plate for load terminal
compartment and shall cover power input compartment. Provide an RF gasket
for load terminal compartment cover plate. Secure cover plate with bolts
having maximum spacing of 75 mm 3 inches. Fabricate access cover plates of
steel not less than 14 gage, and having the same finish as specified for
the enclosure. Attach plates so they may be easily removed and replaced.
2.3.7
RF Attenuation Requirements for Load Terminal Compartment
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NOTE: Use 100 dB insertion loss at 14 kHz to 10 GHz
for applications such as Red/Black communications
installations. Refer to MIL-HDBK-232A for filter
installation requirements in communications
facilities. For other applications, insert
appropriate insertion loss and frequency range for
the specific product. Most often, 400-Hz power line
filters require power factor correction of the
capacitors in the power line filters to reduce
excessive reactive current. Consult filter
manufacturer for detailed requirements. Consult
manufacturer also 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.
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Load terminal compartment shall provide an attenuation of not less than
[100] [_____] dB to radiated RF energy from [14 kHz to 10 GHz] [[_____] to
SECTION 16280N
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