supply of on load tap changer for bgr ( npc ) -50mva , oltc for bgr 50 mva-120729 on load tap changer with motor drive mechanism . conforming as per the order specification sheet sg0100sc , tap changer specification sheet ed/aop15/120729/03 & npcil technical specification sheets pages 20~24 , 43~47 , 58 , 72 , 177&178 ( full specification as per our enquiry ) , spares of bge oltc-120729 spares should contain the following items 1 . oltc motor - 1 no . 2 . dm window glass gasket - 1no . 3 . dm position indicating resistors ( pir ) - 1 set 4 . dm aux . transformer - 1no . 5 . dm lamp - 1 no . 6 . door switch - 1no . 7 . mcbs - one of each type/rating 8 . power contactors for oltc motor - one of each type/rating 9 . oil surge relay - 1 no . 10 . bearing for oltc motor - 1set .