ARMY TM 9-6115-604-12
NAVY NAVFAC P-8-633-12
SECTION VI. RADIO INTERFERENCE SUPPRESSION
4-9. GENERAL METHODS USED TO ATTAIN PROPER SUPPRESSION . Essentially, suppression is attained by
providing a low resistance path to ground for stray currents. The methods used include shielding the wires, grounding the
frame with bonding straps, and using a filtering system.
4-10. INTERFERENCE SUPPRESSION COMPONENTS.
a.
Primary Suppression Components. The primary suppression components are those whose primary function is to
suppress radio interference. Voltage regulator VR101 contains an electromagnetic interference (EMI) suppression
assembly to eliminate any possible effects of EMI on the functioning of its component parts. Surge suppression
capacitor C101 grounds radio frequency emissions generated by generator G1 VR101 and C101 are maintained by
higher level maintenance personnel.
b.
Secondary Suppression Components. These components have radio interference suppression functions which are
Identical or secondary to their primary function. Housing assembly components fully enclose the generator set and
are all grounded. The housing is, effectively, an RFI shield for the entire generator set.
NOTE
Check with local facility engineer to be sure generator set will not produce RFI
detrimental to the operation of electronic equipment. This is especially Important
near air fields and missile sites.
SECTION VII. MAINTENANCE OF HOUSING ASSEMBLY
4-11. GENERAL. Unit maintenance of the housing assembly consists primarily of removal, repair or replacement of
damaged components, and re-installation after repair/replacement
4-12. FAN AND MOTOR ASSEMBLY B103, FAN SHUTTER ASSEMBLY, FIRE EXTINGUISHER BRACKETS, DESK
TOP, AND DOCUMENT COMPARTMENT . Maintenance of the fan and motor assembly B103, fan shutter assembly,
desk top, and document compartment is accomplished by replacement of damaged components or strengthening and
welding, if possible. The fire extinguisher is rechargeable.
a.
Fan and Motor Assembly B103.
(1)
Test.
(a)
Set control room circuit breaker CB109 (5, Figure 2-8), located In distribution panel DP1 to ON, fan and motor
assembly B103 (4, Figure 4-11) should operate
(b)
If fan and motor assembly B103 (4) does not operate, ensure that fan rotates freely by inserting a screwdriver
through the fan grill and manually rotating the fan.
(c)
If fan and motor assembly B103 (4) does not rotate freely, check for mechanical obstructions, or bent or
broken blades
(d)
If fan and motor assembly B103 (4) rotates freely, check for presence of 120 V ac at fan motor electrical wires
In the conduit box mounted to the fan motor housing.
(e)
Test the motor start capacitor. Using a multimeter, set on RX1 scale, perform a continuity check on the
capacitor. The multimeter should read Infinity. If the multimeter Indicates a closed circuit, the capacitor is
shorted and must be replaced.
(f)
Replace the fan and motor assembly B103 (4) if 120 V ac is present and fan does not operate.
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