3-phase 200Vac rectifier output voltage
AC voltages that are stated simply as "nnn VAC" are assumed to be RMS voltages unless otherwise specified. Three-phase voltages that are stated that way are assumed to be line-to-line voltages unless otherwise specified. The circuit shown shows no neutral connection, so that also indicates the line-to-line voltage is the voltage of interest. The source could be delta or wye with no neutral connection to the circuit. Either way, the line-to-line voltage is what the circuit uses.