MIL-DTL-17060G(SH)
6.6.26.7 Design FF. Design FF motors have characteristics similar to design F motors except that the starting
torque is lower than design F.
6.6.27 Synchronous motor. A synchronous motor is a motor in which the average speed of normal operation is
exactly proportional to the frequency of the system to which it is connected. Synchronous motors usually have
direct current field excitation.
6.6.28 Thermal protection (inherent overheating protection). Thermal protection is provided by a protective
device embedded in the motor winding which is responsive to motor temperature whose purpose, when applied to a
motor, is to protect the motor against excessive overheating due to overload or failure to start.
6.6.29 Variable speed drive (VSD). An electronic device used to control the speed of an AC induction motor
or permanent magnet motor.
6.6.30 Variable speed drive (VSD) motor. An electric motor designed in consideration of the additional losses
and mechanical and dielectric stresses associated with VSD operation such that motor life will not be reduced from
that obtained when operated directly from ship's service power.
6.6.31 Variable speed drive motor applications. The success of a VSD motor application is dependent on
adequate information sharing between the motor and VSD manufacturers and the system integrator or shipbuilder.
A complete description of system operation including duty cycle, torque characteristics, distance between VSD and
motor and method of common mode grounding of the motor and drive must be provided to the motor and VSD
manufacturers to ensure equipment suitability.
6.6.32 Motor maximum safe rotating speed. The maximum speed of rotation is the limiting speed for a rotor or
field assembly beyond which, machine reliability can not be guaranteed. The limiting speed is determined in
consideration of the forces acting on the rotating assembly and the limits of lubrication and bearings.
6.7 General packaging requirements.
6.7.1 Navy fire-retardant requirements.
a. Lumber and plywood. Unless otherwise specified (see 6.2), all lumber and plywood including laminating
material used in shipping container construction member, blocking, bracing, and reinforcing should be fire-retardant
treated material conforming to MIL-L-19140 as follows:
Levels A and B -
Type II weather resistant
-
Category 1 general use
Level C
-
Type I non-weather resistant
-
Category 1 general use
b. Fiberboard. Fiberboard used in the construction of unit containers should conform to the class-
domestic/fire retardant or class-weather resistant/fire retardant material requirements of ASTM D4727/D4727M, as
specified (see 6.2).
6.8 Preservation, packing, and marking. Motors should be preserved level A or C and packed level A, B, or C
as specified (see 6.2) and marked in accordance with MIL-E-16298 and should include bar codes and applicable
packaging acquisition options therein as specified (see 6.2).
6.9 Special requirements (low noise surface ship and submarine motors).
a. The methods for handling and packaging each low noise motor should be selected to ensure the low noise
performance is not compromised.
b. In addition to the marking specified in 6.9, the top and side surfaces of shipping containers for low noise
motors should be clearly marked as follows, "CAUTION: LOW NOISE MOTOR - HANDLE WITH CARE".
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