case of each filter shall be attached to both the enclosure and to the
barrier plate to prevent undue stress being applied to the rf seal between
the filter case and the rf barrier plate. Individual filters shall be
removable from the enclosure. Like filters shall be interchangeable.
2.6.1.2
Conduit Connections to Enclosures
The load terminal and input compartments shall have no knockouts, and each
compartment shall have weldable threaded conduit hubs. The hubs shall be
circumferentially EM welded in place and shall be sized and located as
required for the conduits indicated.
2.6.1.3
Access Openings and Cover Plates
Enclosures shall have separate clear front access cover plates on terminal
and power input compartments. Access cover plates shall be hinged with EM
gaskets and 75 mm 3 inch maximum bolt spacing. The design shall include
thick cover plates and folded enclosure edges to prevent enclosure
deformation, bolt spacers to prevent uneven gasket compression, and gasket
mounting to facilitate replacement. All gasket contact areas shall be
tin-plated using the electrodeposited type I method in accordance with ASTM
B 545. Nuts and bolts shall be permanently fastened to the enclosure by
welding or captive attachments.
2.6.1.4
Operating Temperature
The filter and ESA assembly shall be rated for continuous operation, with
filters at rated voltage and full-load currents, in ambient temperatures
from minus 55 to plus 65 degrees C (measured outside the EM filter
enclosure). Filter components shall be suitable for continuous full load
operation at a temperature from minus 55 to plus 85 degrees C.
2.6.1.5
Short Circuit Withstand
Filters shall be labeled and built to have standard short circuit withstand
ratings in accordance with UL 1283. The minimum ratings shall be as
follows:
FILTER RATED
SHORT CIRCUIT FULL LOAD
CURRENT, RMS AMPERE
AMPERES SYMMETRICAL
0-100
10,000
101-400
14,000
2.6.1.6
Filter Connections
Individual filters shall have prewired standoffs and solderless lugs. The
lugs shall be of the hexagonal head bolt or screw type and shall conform to
UL 486A-486B. Live parts shall be spaced in accordance with NFPA 70.
2.6.2
Internal Encapsulated Filters (Filter Units)
**************************************************************************
NOTE: There are two kinds of power filters,
commonly known as "W" and "X" series. The "W"
series filters are designed to achieve rated
insertion loss under load when tested in accordance
with MIL-STD-220, which only requires testing under
load conditions from 100 kHz to 20 MHz. The "X"
SECTION 13095A
Page 29
Previous Page
