ActronAir MPW40 Contactor Link Module MPW40-ECCMP-40B38 connects the WEG MPW40 motor protection circuit breaker directly to a WEG contactor in commercial ActronAir control boxes, providing a mechanical and electrical link that allows the MPCB to directly control the contactor without separate wiring in installations rated below 15kW. Incorrect assembly of the link module causes the MPCB and contactor to operate independently, removing the motor protection function from the compressor or fan circuit it protects. Isolate power at mains before replacing any contactor link components.