It is an automatic UA controller of source changeover system for ComPact NSX, ComPact NS and MasterPact devices. It allows the transfer from one source to another one, the engine generator set start-up and the load shedding. It may be installed directly on the Transferpact ACP control plate or mounted on the front panel of the switchboard. The control voltage is from 380VAC to 415VAC 50/60Hz, or 440VAC 60Hz.