The NAP2 PAC consist of a 50 Hz 4-pole sleeved bearing 2.6 MW electric motor driving from one end a step-up gearbox which is coupled to a hot gas expander, fitted with tilting pad bearings, via a gear type coupling. The remaining end of the motor drives a three-stage integral gear compressor (12,553, 17,934 & 25,174 rpm) via a gear flex coupling. The NAP2 PAC was completely overhauled in March/April 2019 during a scheduled turn-around period, conducted every 5 years, inclusive of a motor rotor replacement, step-up gearbox overhaul, a new air end compressor installation as well as hot gas expander thrust bearing and thrust collar replacements/repairs. Additionally, the expander seals were replaced with like-for-like but tighter clearance carbon seals, the entire drive train was re-aligned and a new anti-surge valve was installed.