NCTPS I ES Circle EM II Division S Dn I Repair and rewinding of 1 No failed HT mill motor released from location 2D BHEL make 6 6 KV 380 KW 590 RPM Frame Size ILA 7714 8H70 Z Sl No 44170 A 401 21 02

Amount

STATOR REWINDING (6.6 KV) GVPI Charges towards dismantling the motor, threading out the rotor from the stator core pack, stripping out of old windings, cleaning the slots, conducting hot spot test find out the core damages, removing the stator core pack from the stator yoke by hydraulic press using special jigs and fixtures, rewinding the stator using class ‘F’ enamelled polymica covered electrolytic grade rectangular copper conductors for rewinding coil as per the Original shape and dimension by uing special jigs and dies as detailed in Sl.No.2), pre-staggering the coil with thermopreg, insulating the slot portions using samicapor insulating materials, applying corona protection tapes and stress grading tapes, inserting the coils in to the slots, banding the overhang portions in the surge ring, forming the end connection, fixing 12 Nos. RTDs, preheating, Global Vacuum Pressure Impregnating the winding with core pack in vacuum chamber using suitable poly epoxy resin, baking, testing, refixing the core pack into the stator yoke with special jigs and fixtures in hydraulic press, providing flexible silican cables, applying finishing varnishes including assembling, no load trial run and measuring all no load parameters. Materials: class F” enameled polymica covered electrolytic grade rectangular copper conductors, samicapor insulating materials, corona protection tapes, stress grading tapes 12 Nos. RTDs, poly epoxy resin flexible silicon cables, varnishes.

STATOR CORE RESTACKING: Charges towards mounting the stator body in hydraulic press, removing the core pack from stator body with special tools and machineries after heating the stator yoke with special heating arrangements, segregating the damaged stator core from core pack, removing the old burnt core plate varnishing by chemical treatment, cleaning, removing the surface kinks. Varnishing the stampings in re-varnishing cum conveyor oven to cure the core plate varnish, staggering the core with special tools and machineries, locking and repositioning the core pack to the stator body by hydraulic press and finally conducting the flux loop test to ascertain the restacked core healthiness, cleaning and polishing the slots ready to feeding. Material: New Stator core plate, core plate varnish

ROTOR TESTING & SERVICE: Charges towards threading out the rotor from the stator core pack, cleaning the rotor winding thoroughly using high pressure water, drying out the winding, conducting non- destructive test to the rotor bars and end rings, to ascertain the healthiness of the winding, visual inspecting the rotor in all electrical and mechanical parts, preheating, varnishing and backing in oven, applying finishing varnishes to the rotor , checking the shaft trueness, measuring the bearing fitting tolerance both in housing and rotor shaft. Material: Varnish

ROTOR – RE-BARRING: Changes towards mounting the rotor in the lathe, machining both side end ring, stripping out the bars in bar removing machine using special tools and machineries, machining the rotor bars & 2 Nos. end rings made out of electrical conductivity grade copper using copper bars & copper end rings, inserting the rotor bars using special tools and machineries, positioning, locking, machining both side rotor bars for proper bedding of bars and end rings, brazing the bars and end rings using silver brazing rods, flux & OXY- acetylene gas and thermal protection materials, conducting the healthiness of the brazed joints before and after machining the excessive materials, cleaning, dip varnishing the rotor with class F varnish, baking, applying finishing varnishes to the overhang portions (if required).

ROTOR CORE REPLACEMENT: Charges towards machining the core locks, removing the core pack form rotor shaft with special tools and machineries after heating the rotor core pack with special heating arrangements, procuring the new stampings with exact to the original dimensions with suitable grade material, staggering the core with special tools and machineries, locking and repositioning the core pack to the rotor shaft by hydraulic press and finally conducting the flux loop test to ascertain the stacked core healthiness, checking the rotor shaft trueness, cleaning and polishing the slots ready to feeding (if required)

Charges for providing the DE side housing bearing seating sleeve. Material : Cast iron

Charges for providing the NDE side housing bearing seating sleeve. Material : Cast iron

Charges for providing the NDE side new outer cup collar. Material : Cast iron

Charges towards welding with special electrodes, stress reliving and machining the DE & NDE side bearing step, Pully area (Shaft dia =140 mm) Material : Cast iron & special welding Electrodes

Charges towards dynamically balancing the rotor to grade G2.5 at rated RPM

Charges for providing DE side new circlip

Charges for providing NDE side new circlip

Charges for providing both side BTD with adaptor

Bearing No. 6230 C3 (steel cage)

Bearing No.NU 226 EM-I C3 (Brass cage)

Bearing No. NU 230 EM I C3 (Brass cage)

Providing NDE side inner grease cup

Providing NDE side outer grease cup

Charges for providing space heater

Rectification of cooling fan with dynamic balancing work

Cooling fan cover rectification work

Charges for providing flat type oil seal

To and fro transport charges (From NCTPS-I to factory premises) approx = 500Kms.

II.cost of copper and old bearing scrap retrieved from the motor: Less old stator scrap

Less old rotor scrap

ATHI ELECTRIX COMPANY