Repair & Re-Winding of 18KW Circular Lifting Magnets for SPC bay & Wheel shop Cranes.

1-Repair & Re-Winding of 18KW Circular Lifting Magnets for SPC bay &

1. Lifting of defective circular magnet from RWF/YNK to firm's premises and bring back the same to RWF/YNK after the repair and rewinding of the defective magnet. To & fro transportation charges are under the scope of contractor. 2Opening of Bottom Cover & removal of Filler material from magnet. 3Removal of Faulty copper windings from the magnet, burnt scrap copper coil. - Released copper shall be retained by Firm. The rate quoted shall be considering the salvage value. The weight of copper released and the approximate price of this released copper shall be shared to SSE/EL/ASC & SSE/EL/WSC 4Cleaning of magnet housing. 5Preparation of new coils required for magnet as per original design and weight. For magnet coils special design foil coil would be used to have greater forge index and best heat dissipation. Copper used shall be with 99.99% purity. Test certificate for copper shall be submitted. 6Copper conductor should be of copper strips for electrical purposes and shall be free from burrs and will not have more than 2 joints in any single coil/cake. The joints shall be lap jointed and brazed all round. There shall be no joints in the portion of the coil immediately connecting to the leads for at least six turns. The last lap of the coil shall be reinforced with a phosphor-bronze strip. Application of Anti-moisture epoxy based Dr.Beck get coat red varnish. Class C red varnish. Class of insulation : Class 'C' Dupont Nomex Inter-turns. Body insulation shall be of Mica sheet. 7Annular space between the coil and magnet body shall be filled with filler material of silicon rubber compound class C, hermitically sealed. The filling compound shall be non-hygroscopic and shall have low co-efficient of thermal expansion and high thermal conductivity. The magnet shall be able to withstand the rise in temperature corresponding to the class of insulation and shall be easily removable during the repair of the magnet. 8Test coil continuity and coil resistance of magnet. Terminal lead shall be inserted in a Teflon bushing and to be terminated at new terminal block. Terminal block and top cover shall be repaired as per original design. 9Discharging the magnet by putting non linear resistor( surge suppressor) in the magnet gland box. 10Electrical Connectors- Plug in connectors made of 25mm2, 2 conductor type "W" magnet cable, 2000VDC rated for durability and ease of replacement. 11Seal Plate- Additional protection from moisture and impact is provided with a non magnetic manganese sealing plate. 11Testing of Magnet: Test Shall include: 1.Physical inspection 2.DC resistance measurement at Ambient temperature. 3.Magnet Insulation test using Megger 4.Heat Run Test 5.High voltage test by applying 2000V for 30 seconds 6.Magnet test on site using solid load on a test rig for tear off capacity check. 12Painting of Magnet before despatch.