NATIONAL ALUMINIUM COMPANY LIMITED - Rites

All AC squirrel cage induction motors shall be fed at 415V V from switchboard through air circuit
breakers with numeric type compreh comprehensive motor protection relays via power contactor and
overload relay.
g) System Earthing
33kV system is unearthed, , 415V system is solidly earthed.
2.6 ELECTRICAL SYSTEM REQUIREMENTS
Minimum number of spare feeders in each of the MCC / PDB / LDB / SLDB shall be 10% subject
to minimum one no. of each type and rating in each section. The rating a aand
type of spare
feeder shall be decided during detailed engineering stage.
Sizes and requirement of various power and control cables shall be decided and intimated to
the Purchaser well in advance to suit the approved scheme/to achieve scheme requiremen requirement.
Space heater power supply to the motors shall be fed from the MCC through same cubicle by
415/240 V transformers. Space heaters shall be interlocked with motor main power supply.
Bidder to submit a system wise drive list indicating required process in interlocks, permissive
conditions etc. with places and mode of control, control system philosophy with provision of
various control, indication, measuring devices at various places. The Purchaser Purchaser/RITES shall
approve this based on above approved philosophy an and d Bidder shall have to provide all
equipment / materials and prepare a control scheme/logic diagram which shall be utilized for
designing the motor feeders at 33 kV switchboard and 415 V MCC at Bidder’s end.
Above-mentioned mentioned control philosophy and interlocking logic shall be prepared as per the
technological requirement.
Suitable electrics for all the material handling equipment like hoist, etc shall be provided for
handling the various drives and mechanism.
Warning hooter shall be of brushless type Siren and AC single phase.
All actuators shall be of geared motors.
Complete 24 V system, wherever required, shall be provided by the bidder.
24 V and 230 V AC shall be taken through separate cables. Screene Screened d cables shall be supplied
and used for 24 V power supply.
All the indication lamps shall be LED based with LVGP (Low Voltage Glow Protection) up to 100
V.
All the hoist control panel shall be located at workable height and platform shall be provided
for r each hoist at one point for maintenance purpose.
Technical Specification:Sec-6, Electrical
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