Repair to the rotor of 620 HP Motor of Manda Unit No-04 installed at CPS Sitlee.

Repair to the rotor of 620 HP squirrel cage induction motor by replacement of damaged and fractured end rings. The job includes dismantling of the motor and removal of rotor assembly from the stator, followed by thorough cleaning of the rotor to remove dust, grease, carbon deposits, and other contaminants. The damaged, cracked, and fractured rotor end rings shall be carefully inspected and removed without causing any damage to the rotor bars or rotor core. The rotor bars and core shall also be checked for continuity, alignment, and any additional defects before carrying out further repair works. New rotor end rings of suitable grade copper matching the original OEM specifications shall be fabricated/procured and machined to the required dimensions and tolerances. The rotor ends and contact surfaces shall be properly cleaned, dressed, machined, and prepared to ensure correct seating and fitment of the new end rings. The new end rings shall then be fitted and secured with the rotor bars by suitable brazing/welding/shrink-fit process to achieve proper electrical continuity and mechanical strength. All welding/brazing works shall be carried out carefully to avoid distortion and to maintain rotor integrity. The rotor assembly shall be checked for concentricity, alignment, and dimensional accuracy. Necessary insulation touch-up using suitable insulating varnish shall also be carried out wherever required during the repair process. The repaired rotor shall thereafter be reassembled with the motor, including proper fitting of bearings, bearing covers, cooling fan, coupling and other associated accessories. The motor shall be carefully refitted on the existing base frame/foundation and properly aligned with the pump using suitable alignment instruments to ensure correct shaft alignment and coupling accuracy. Re-coupling of the motor with the pump shall be carried out complete in all respects. After completion of reassembly and alignment works the complete motor-pump unit shall be tested on load under operating conditions to ensure satisfactory performance, smooth operation, proper current consumption, absence of abnormal vibration/noise, and reliable functioning of the repaired motor at site. All safety precautions during dismantling, machining, welding, assembly, alignment and testing shall be strictly followed. The work shall be completed in all respects and the repaired motor unit shall be made fully fit for satisfactory operation and commissioning. Rebate on old parts if any to be quoted separately.