NATIONAL ALUMINIUM COMPANY LIMITED - Rites

lifted over/by the side of other equipment’s without removing the later. The necessary
levels of floors in various buildings shall be decided considering the above requirement.
14.2.3 Monorails shall be extended outside the building to handle the equipment to g gground
level.
For monorail/hoist routed inside the buildings, suitable machinery well and removable
handrailing and grating shall be provided on various floors of buildings, as necessary, to
handle the equipment.
14.2.4 Electrically operated monogirder typ type e hoists shall consist of following major components.
a) Electrically operated trolley complete with drive motor (Trolley travel speed maximum 15
m/min.).
b) Hoist cable, hoisting block and hooks complete with drive motor (Hoisting speed
maximum 6m/min.).
c) Limit switch to prevent overhoisting, over lowering and over travel.
d) Festoon arrangement of feeding power to trolley assembly.
e) Erection hardware.
f) Pendent control station suspended from hoist.
g) Control Panel mounted on wall.
14.2.5 The electric hoist shall be de designed signed and constructed in accordance with the latest revision of
IS:3938 and shall be suitable for duty class 2.
14.2.6 For electric hoists, trolley movement and hoisting shall be effected by using two separate
motors. Motors shall be as per technical re requirements quirements discussed elsewhere. However the
motors shall be suitable for 150 starts per hour at 40% CDF.
14.2.7 Trolley for motorized / manual cross travel shall be designed to accommodate a wide range
of I beams and shall be capable of travelling on straight as well as curved monorails with the
design being such to maintain uniform distribution of pressure on the flanges.
14.2.8 Motor operated geared trolley shall have two (2) pairs of wheels, one pair of which shall be
driven through motor.
14.2.9 Wire rope shall be of pre pre-formed formed type, hemp cored, regular lay 6/36 construction with a
breaking strength of 160 -175 175 kgf/ sq. mm. Reverse bend of ropes is not acceptable.
Minimum number of falls of rope shall be four (4).
14.2.10 All gears and pinions shall be of hardened and tempered steel with machine cut teeth in
metric modules. Surface hardening of steel is not acceptable.
14.2.11 All running shafts and wheels shall be fitted with roller bearings with a rated life not less
than 20 years based on eq equivalent running time as per IS:3938.
14.2.12 An electromechanical brake shall provided for hoisting as well as cross travel. Brake lining
shall be of asbestos.
Technical Specification:Sec-4,System System Parameters, Operation & Control Philosophy
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