The reference 54444 is an external 24 VDC power-supply module, it takes as input 200-240Vac and outputs 24Vdc.
An external 24 V DC power supply is required for installations with communication, whatever the type of trip unit as the comunication modules for the ACB requires an external 24Vdc supply, on installations without communication, it is available as an option for Micrologic 5/6, in order to make it possible to:
1) modify settings when the circuit breaker is open
2) Display measurements when the current flowing through the circuit breaker is low
(15 to 50 A depending on the rating)
3) Maintain the display of the cause of tripping and interrupted current