Rebuild or replace motor control centers as part of a control system upgrade

The need to upgrade and modernize plant control systems has been fairly widely accepted in the cement industry. A modernization project may range from a simple upgrade of HMI computers to a complete replacement of all hardware and software. Motor control centers (MCC) to a lesser degree age and begin to fail. Single MCC starter replacement is effective while spares are available, however many cement plants now face the dilemma of dysfunctional MCCs and limited and expensive spares. Complete replacement of an MCC section is an ideal solution, however this is often cost prohibitive and logistically difficult. A less costly alternative often considered is the partial upgrade of an MCC. This paper reviews two projects where MCC refurbishments (contactor, overload, and control relay) were performed in parallel with a control system upgrade, resulting in considerable savings.