Fuji Electric FRENIC-HVAC User Manual page 407

Timing Scheme
Switching from inverter operation to commercial-power operation
ISW50/ISW60: ON → OFF
(1) The inverter output is shut OFF immediately (Power gate IGBT OFF)
(2) The inverter primary circuit SW52-1 and the inverter secondary side SW52-2 are turned
OFF immediately.
(3) If a run command is present after an elapse of t1 (0.2 sec + time specified by H13), the
commercial power circuit SW88 is turned ON.
Switching from commercial-power operation to inverter operation
ISW50/ISW60: OFF → ON
(1) The inverter primary circuit SW52-1 is turned ON immediately.
(2) The commercial power circuit SW88 is turned OFF immediately.
(3) After an elapse of t2 (0.2 sec + time required for the main circuit to get ready) from when
SW52-1 is turned ON, the inverter secondary circuit SW52-2 is turned ON.
(4) After an elapse of t3 (0.2 sec + time specified by H13) from when SW52-2 is turned ON,
the inverter harmonizes once the motor that has been freed from the commercial power
to the commercial power frequency. Then the motor returns to the operation driven by
the inverter.
t1: 0.2 sec + Time specified by H13 (Restart mode after momentary power failure)
t2: 0.2 sec + Time required for the main circuit to get ready
t3: 0.2 sec + Time specified by H13 (Restart mode after momentary power failure)
6.3 Details of Function Codes
6-97