corrigendum - notice inviting tender for procurement of design , manufacture , installation , testing and commisioning of 15 kva , single phase , 115 volts , 50 hz , ups system set for urea plant . as per nit , supply material at rcf trombay unit , design & manufacture and supply of 15 kva , single phase , 115 volts , 50 hz , ups system set for urea plant . , decommissioning , removal of old existing ups system and installation , testing and commisioning of new 15 kva , single phase , 115 volts , 50 hz , ups system set for urea plant . , buyback of old existing ups system consisting of 2 nos . of ups and 2 nos . of avr/svr , comprehensive annual maintenance charges for first year ( after completion of guarantee period ) , comprehensive annual maintenance charges for second year ( after completion of guarantee period ) , comprehensive annual maintenance charges for third year ( after completion of guarantee period )