MIL-DTL-17060G(SH)
3.5.1.20 Frames and covers. The finished motor frame shall be one piece. Loose spacers or any form of frame
extension not welded or permanently attached to the frame or end shield shall not be used to extend the length of the
frame. End shields shall be secured to the frame with not less than four hexagonal head or socket-head screws or
bolts. Motor construction shall be based on the use of bolts or screws of tensile strength not greater than that for
Grade 5 in accordance with MIL-DTL-1222. Through bolts may be used to secure the end brackets to the frame of
motors built in a frame size 215 or smaller, except for explosion proof enclosures. Bolts shall be fitted with
lockwashers in accordance with MIL-E-917. Enclosing covers (hand-hole or access-hole covers) shall be readily
removable. Engaging bolts or locking devices shall be attached to the frame, end shield, or covers as the
construction permits in such manner as to prevent the bolts or locking devices from being misplaced or dropped into
the machine during repair operations. Motors shall be provided with a means to permit easy removal of end shields
Knock-off lugs integral with end bracket
a.
b.
Holes drilled and tapped in end shield for use of jacking bolts
c.
Recess in frame to permit contact of drift with end shield flange
3.5.1.20.1 Vertical fan-cooled motor covers. Vertical fan-cooled motors shall be furnished with a solid cover
over the fan assembly to prevent personnel injury and to prevent foreign particles from falling into the fan.
3.5.1.20.2 Aluminum frames and end shields. Except for non-magnetic applications, aluminum alloys shall not
be used for motor frames or end shields. Where used, aluminum shall be hard anodized in accordance with
MIL-A-8625, Type 3, Class I or II, or SAE AMS2469. End shields shall not support the total weight of the motor
driven auxiliary. Steel inserts shall be provided for all threaded positions and bearing housings.
3.5.1.21 Shafts. Unless otherwise specified (see 6.2), a shaft extension with keyway shall be provided and shall
be in accordance with figures 1, 2, 3, and 4, as applicable (for submarine applications see 3.5.2.5.6).
3.5.1.22 Bearings. For additional bearing requirements refer to 3.5.2, as applicable.
3.5.1.22.1 Types of bearings. Unless otherwise specified (see 6.2), bearings shall be the ball type.
3.5.1.22.2 Ball bearing lubrication. Except as determined in accordance with 3.5.2.1.5.1, ball bearings shall be
grease lubricated.
3.5.1.22.2.1 Lubrication and preservation. Except for motors using double seal or cartridge bearings, the
following shall occur prior to the motor leaving the plant of manufacture:
a.
The correct amount of clean grease shall be added to the grease reservoirs.
b.
The piping and grease passages leading to the grease reservoirs shall be filled with clean grease.
c.
A thin coat of clean grease shall be applied to the surfaces of the grease reservoir.
Grease shall be in accordance with DOD-G-24508. Where oil is the lubricant, the bearings shall be treated with a
preservative compatible with the operating oil.
3.5.1.22.2.2 Lubrication provisions. Except for motors with double seal or cartridge bearings, motors shall be
relubricable and shall not require disassembly for relubrication. Grease cups, pipes, where applicable, and drains
shall be used when grease is a means of lubrication and relubrication of bearings is required. The grease cup shall
not be mounted on the motor and the threaded hole used to attach the grease cup shall be provided with a pipe plug
or cap. Grease inlet and drain passages shall be of minimum length. For motors critical to ship's mission (see 6.2),
grease passages shall be cleanable without motor disassembly, other than removal of any grease pipes. Grease pipes
shall be removable without motor disassembly. Grease pipes, where used, shall be left on the motor; the end
outermost from the motor shall be fitted with a pipe plug. Pipe plugs shall be accessible without motor disassembly.
The grease inlet shall be located on or above the horizontal centerline of the bearing housing for horizontal motors
and at any location convenient to the grease chambers above the bearing for vertical motors. Grease outlets shall be
located to afford maximum purging of grease during regreasing operation.
3.5.1.22.2.3 Grease lubricant seals. Except where double seal or cartridge bearings are used, the bearing
housing shall provide for a close clearance, metallic, nonrubbing seal on both sides of the bearings to prevent the
leakage of oil or grease along the shaft. This is in addition to bearing shields or slingers, if required.
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