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|  MIL-C-52128C
and other electrical devices. Plug-in-type connections in branch circuits shall have a positive
lock or other effective means to prevent accidental disconnection caused by vibration. The
contractor shall furnish a wiring diagram showing each wire in the system number coded near
each connector.
3.8.2.2 Motor-mounting brackets. All motors shall be provided with mounting brackets.
When a 5-horsepower (hp) motor is specified herein, the mounting brackets shall also be of
sufficient size and shall be provided with mounting holes to accommodate a 10-hp motor for
emergency replacement.
3.9 Drives.
3.9.1 Chain drives. Unless otherwise specified herein, chains used in drive trains shall be in
accordance with ANSI B29.1 and shall conform to MIL-STD-423 and MIL-STD-424 as
applicable. Chain drives shall be installed with idlers and other methods for providing
adjustment.
3.9.2 V-belt drives. V-belt drives shall be in accordance with ANSI B55.l or Rubber
Manufacturers Association, Inc., "Engineering Standard for Drives Using Narrow V-Belts
(3V, 5V; and 8V Cross Sections)". Belts used on multiple V-belt drives shall be matched sets or
banded together by a tie band. Jack shaft drives may be used. All V-belt drives shall have
provisions for adjustment.
3.9.3 Gear drives. Gear drives shall be totally enclosed and shall run in an oil bath. Cast
iron gears when used shall conform to ASTM A536. The analysis and heat treatment shall be as
recommended by the contractor. When cast iron gears are provided, the pinion shall be of steel.
3.9.4 Shafting. Shafting 2 inches in diameter and larger shall be of steel in accordance with
ASTM A193, type B7, Rockwell hardness 25 to 32 on Rockwell "C" scale and shall be turned,
ground, and polished. The fit tolerance between all shafting and driven members shall not
exceed 0.003 inch.
3.9.5 Keys and keyways. All keys and keyways on the crushing component (see 3.12),
except where tapered hubs or taper-lock bushings are used, shall be in accordance with Figure 1.
Keys shall be at least as hard as the shafting.
3.9.6 Torque arm speed reducers. On torque arm speed reducers, the torque arm shall be
attached to the speed reducer housing by means of one or two brackets. Each bracket shall be
attached to the speed reducer housing by not less than two bolts. The torque arm shall be at an
angle of 90 degrees plus or minus 30 degrees with a line drawn between the output shaft and the
point at which the torque arm is attached to the speed reducer. If the torque arm is used to
tighten the drive belt or chain, the drive shall be at an angle of 90 degrees plus or minus
10 degrees with a line drawn between the input and output shafts of the speed reducer. The
angular measurements specified herein shall apply when the drive belt or chain is properly
adjusted for tension. Concentric loading shall be provided on speed reducer housing when the
torque arm is used for drive belt or chain tension adjustment.
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