MIL-DTL-17060G(SH)
3.6.3 Noise.
3.6.3.1 Airborne noise. Unless otherwise specified, the airborne noise of motors shall not exceed the limits in
table VI (see 4.6.5.1). For submarine and surface ships applications requiring airborne noise levels quieter than in
table VI or for motors without an applicable baseline requirement in table VI, the motor airborne noise requirement
necessary to allow the auxiliary equipment to meet its requirement shall be specified in 6.2. Mufflers shall not be
used with motors rated less than 200 hp. When specified (see 6.2), motors rated 200 hp and larger may use mufflers.
For VSD motors, the following is applicable:
a. For the purpose of determining the applicable requirement in table VI, the motor's horsepower rating and
synchronous speed shall be that associated with operation at base speed (see 6.6.25.6).
b. The requirement, as determined in 3.6.3.1.a, is applicable to testing per 4.6.5.3 when testing at the base
speed or at a maximum operating speed greater than base speed.
TABLE VI. Airborne noise limits (sound pressure levels in decibels (dB) referenced to 20 micropascals (µPa)). 1/
Synchronous
Octave band center frequency in Hz
Enclosure
2/ 3/
hp
speed
type
31.5
63
125
250
500
1K
2K
4K
8K
(r/min)
≤1800
ALL
DPP
85
80
79
75
71
69
67
67
67
1-150
DPP
3600
85
80
79
76
75
71
70
69
68
4/
>150
DPP
3600
1-75
All others
3600
85
80
79
76
75
71
70
69
68
≥100
4/
All others
3600
≤1800
All
All others
85
80
79
76
75
71
70
69
68
NOTES:
1/
Limits are established for the direction of motor rotation required by the driven auxiliary. No limits are defined
for opposite rotation.
2/
Motors rated 200 hp and above may use noise kits when approved (see 6.11).
3/
For each speed rating, horsepower (hp), for the purposes of table VI, is defined as the smallest value of rated hp
applicable to a motor.
4/
Airborne noise levels shall be specified by the procuring activity.
3.6.3.2 Structureborne noise.
3.6.3.2.1 Low noise surface ship applications. The motor structureborne noise requirement necessary to allow
the auxiliary equipment to meet its requirement should be specified in 6.2. If a motor requirement is not specified in
6.2, the structureborne noise limits for low noise surface ship applications, (see 6.6.14) shall not exceed the limits
specified in MIL-STD-740-2 for Type II equipment at all frequencies except between 100 hertz and 160 hertz. For
frequencies between 100 hertz and 160 hertz, the structureborne noise shall not exceed the limits specified in
MIL-STD-740-2 for Type II equipment by more than 5 decibels (dB) (see 4.6.5.2).
3.6.3.2.2 Submarine applications. The motor structureborne noise requirement necessary to allow the auxiliary
equipment to meet its requirement should be specified in 6.2. If a motor requirement is not specified in 6.2, the
structureborne noise of motors for submarines shall not exceed the limits specified in MIL-STD-740-2 for Type III
equipment (see 4.6.5.2).
3.6.3.2.3 Additional structureborne noise requirement for VSD motors. In addition to 3.6.3.2.1 and 3.6.3.2.2,
for VSD motors, the structureborne noise requirement shall be met throughout the speed range (see 6.2).
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