The Mitsubishi FR-A840-0.4K-1 is a variable speed / frequency drive in the FR-A840 series, specified for three-phase 400 V supply on the input side and three-phase 380–500 V on the output side. It's the smallest frame in the A840 line — sized for a 0.4 kW motor, with 1.5 A rated output current and 1.1 kVA output capacity. The 150 mm × 260 mm × 140 mm footprint drops into compact sub-panel builds and small MCC drawers without oversizing the panel cutout.
Ratings, comms, and the fit decision
Drive input is three-phase 400 V; output is three-phase 380–500 V at 1.5 A, so the BOM line closes cleanly only against a 0.4 kW three-phase induction motor. Pumping it up to a larger motor means upping the FR-A840 frame, not just reprogramming. The drive carries its own RS-232/422/485 serial port on the unit, so a basic Modbus RTU or Mitsubishi inverter protocol link is wired without an option card. Listed approvals are CE, UL, and cUL, with RoHS 6 — adequate for CE-marked panels and North American factory acceptance.
Same-frame step-up: the 1.5K alternative
Stepping one notch up to the FR-A840-1.5K-1 keeps the same 150 mm × 260 mm × 140 mm enclosure, the same three-phase 400 V input class, and the same RS-232/422/485 comms port — only the output envelope rises (0.4 kW → 1.5 kW; 1.5 A → 4 A; 1.1 kVA → 3 kVA).