2.3.2.5
Bearings
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NOTE: Verify bearing L-10 life requirements.
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Each impeller shaft shall be supported by antifriction [spherical ball]
[roller] bearings sized for a minimum L-10 life of [30,000] [50,000] hours
as defined by ABMA 9 or ABMA 11.
2.3.2.6
Seals
A lip type oil seal shall be provided at each bearing to prevent lubricant
from leaking into the air stream. Labyrinth seals shall be provided at the
point where the shaft passes through the head. Ventilation of the impeller
side of the oil seals to atmosphere shall be provided to eliminate any
carry-over of lubricant into the air stream.
2.3.2.7
Lubrication
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NOTE: Delete inapplicable lubrication system. Use
bracketed sentences if "pressure oil lubricated" is
to be used in the lubrication system.
**************************************************************************
Drive and bearings shall be [grease lubricated and provided with a grease
fitting] [splash oil lubricated]. Timing gears and gear end bearings shall
be [pressure oil lubricated] [splash oil lubricated]. Oil level shall be
regulated by a metering orifice.
[Full pressure lubrication system built into positive displacement blower
shall be direct connected to oil pump and shall include oil strainer, oil
reservoir, piping to bearings, and oil spray for gears with piping to
air-to-oil cooler. Oil vents shall be designed so that oil vapors do not
enter motor. System shall be designed to prevent leakage and dirt
2.3.3
Drive Connection
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NOTE: Verify cfm increments for additional sheaves.
**************************************************************************
[The blower shall be connected to the motor by a heavy-duty flexible forged
steel spacer coupling, keyed or locked to the shaft.] [The blower shall be
connected to the motor by a V-belt drive capable of transmitting the motor
power to the blower. Additional sheaves shall be provided so that the
blowers output can be varied in [0.189] [_____] cubic meter per second [40]
[_____] cfm increments between minimum and maximum flow conditions.] The
drive shall be covered with an acoustically treated sheet metal guard.
2.3.4
Motors
Motors shall be sized to be within their rated load under the specified
operating conditions. Motors shall conform to NEMA MG 1 and shall be the
squirrel cage induction Type NEMA Design B, Class B or F insulated, with a
service factor of not less than 1.15. Motors shall be horizontal
foot-mounted, totally enclosed fan-cooled, cast iron or aluminum
SECTION 11375A
Page 15
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