10.
11.
12.
13.
14320-4
HOIST SYSTEMS
Overload device shall be provided to prevent lifting excessive overloads. This
load-limiting device shall be preset at the factory to disengage the hoist motor
from the gearing in event of excessive overload condition. Overload device is
to be located between the motor and load brake, so that the load brake will
hold the load in event of overload device failure.
Motors shall be of high starting torque type designed specifically for hoist
duty service with permanently lubricated ball bearings, rated for 30-minute
duty cycle. The motor enclosure is to be totally enclosed non-ventilated,
TENV. Motor insulation shall be class F Minimum. Motor is to have
automatic reset temperature actuated switch (TAS) in motor windings to
provide motor running over current protection.
Gearing shall be a combination of spur and/or helical, precision cut and heat
treated to ensure quiet, efficient operation. Gears shall be totally enclosed and
run in a bath of oil to provide maximum lubrication. Gears are either splined
or keyed to shafts.
Deep grooved, large diameter rope drum that helps prevent overwrap of cable
for longer rope life.
The diameter of the rope drum shall not be less than 18 times the diameter of
hoisting cable, running sheaves not be less than 16 times and idler sheave not
less than 12 times the diameter. Hoisting cable shall be stainless steel.
Limit Switch: An upper block operated control circuit limit switch shall be
provided that shuts off the hoist motor when the load hook reaches its highest
position.
Controls to be centralized and designed per NEC (National Electric Code)
standards housed in a panel with a hinged door. The controls are to be
provided with a step-down transformer within the panel that provides 120
volts power to the control circuits. Control circuit voltage to the push button
station shall not exceed 120 volts. In addition, the panel shall be UL Listed.
Pushbutton station shall be of molded contour grip type and supported from
hoist by strain relief cable to avoid damage from pull on the control wires.
The enclosure is to be NEMA 4X watertight. Controls pendant shall be 120
volt AC, supported by a strain cable. Pendant shall hang to a point 3' - 6"
above the operating floor, elevation as shown on the drawings.
All controls, including power transformer, shall be housed in NEMA-4X
enclosure mounted in an easily accessible location on the hoist. Controls shall
include trolley travel, tractor travel and hoist raising and lowering. Limit
switches shall be provided to prevent over travel of the hook in either
direction. Motors shall be fully enclosed 30-minute duty cycle motors in a
NEMA frame rated for 480 volts, 3-phase, 60 Hz power supply.
2.6 ELECTRIFICATION
Electrification other than cable reel shall be insulated (enclosed) conductor bars
mounted on monorail track. The enclosed conductor system shall be supplied
compete with all necessary support brackets, supports insulators, power feeds,
splice assemblies and closures, and transfer insulators.
A.
Dry Well Hoist Replacement
IFB1093-122920
