The FR-D740-120-NA is a 5.5 kW three-phase 400 V AC variable frequency drive from Mitsubishi Electric, belonging to the FREQROL-D700 series — a compact, sensorless vector inverter range designed for general-purpose pump, fan, and conveyor applications in North American market configurations. Atlantech Drives holds stock of the FR-D740-120-NA. Contact us for fast worldwide delivery and competitive pricing.
What Is the Mitsubishi FR-D740-120-NA?
The FR-D740-120-NA is the 5.5 kW (7.5 HP) model of the FREQROL-D740 sub-series, built for 380–480 V three-phase supply systems and carrying North American certifications (UL, cUL). The -120 designation refers to the rated output current of 12.0 A. As part of the D700 series, this drive integrates PID control, auto-tuning, and built-in EMC filter as standard, making it a self-contained solution for variable speed control without requiring external filter components. The D740 sub-series specifically targets three-phase 400 V class installations, distinguishing it from the D720S (single-phase 200 V) and D720 (three-phase 200 V) variants.
Key Technical Specifications
- Rated output power: 5.5 kW (7.5 HP)
- Rated output current: 12.0 A
- Input voltage: 380–480 V AC, 3-phase, 50/60 Hz
- Output voltage: 0–480 V AC, 3-phase
- Output frequency range: 0.2–400 Hz
- Control method: Advanced magnetic flux vector (sensorless), V/F control
- Overload capacity: 150% for 60 seconds, 200% for 0.5 seconds
- Built-in brake transistor: Yes
- Built-in EMC filter: Yes (Class C2)
- Communication: RS-485 (Modbus RTU) via PU connector
- Certifications: UL, cUL (North America), CE
- Enclosure rating: IP20
- Operating temperature: –10 to +50°C
- Dimensions (W × H × D): 140 × 260 × 145 mm
Typical Industrial Applications
The FR-D740-120-NA is designed for duty cycles that do not require constant torque at zero speed, making it particularly suitable for: HVAC fan and pump drives in commercial buildings and industrial plants, where the inherent energy savings from variable speed operation on centrifugal loads deliver measurable ROI; conveyor systems with moderate torque requirements at low speeds; compressor staging in refrigeration and pneumatic systems; and mixer drives where PID-controlled speed regulation to a process variable (pressure, flow, level) is required. The built-in PID controller eliminates the need for an external process controller in simple single-loop applications. For demanding constant-torque applications such as hoists, cranes, or extruders requiring high torque at zero speed, the FR-A700 or FR-F700 series would be more appropriate selections.
Installation Advice
Mount the FR-D740-120-NA vertically in a ventilated enclosure with a minimum clearance of 10 cm above and below the unit, and 2 cm on each side, to maintain adequate cooling airflow through the internal heatsink. At 5.5 kW, the drive’s power dissipation is approximately 110 W at full load — enclosure thermal sizing must account for this in addition to other heat sources. Connect the motor cable as short as practically possible; for cables exceeding 30 m, enable the output side EMC filter function (Pr. 72) to suppress capacitive leakage current that can trigger the drive’s ground fault protection (E.GF alarm). For RS-485 Modbus RTU integration, use the PU connector with an FR-A7DP cable adapter or a standard RS-485 terminal block adapter — do not attempt to wire RS-485 directly to the PU port without the correct adapter as pin assignments differ from standard EIA-485 connectors. Always install an input line reactor on systems supplied from generators or where voltage unbalance exceeds 3%, as the D700 series diode rectifier front-end is sensitive to supply asymmetry.
Frequently Asked Questions
Q: What is the difference between FR-D740-120-NA and FR-D740-120-EC?
A: Both are 5.5 kW 400 V class drives with identical electrical specifications. The -NA suffix indicates UL/cUL certification for North American markets; the -EC suffix indicates CE marking for European markets. The EMC filter class and terminal labelling may differ slightly. Specify the correct variant based on your installation market.
Q: Can the FR-D740-120-NA control a motor with an encoder for closed-loop vector operation?
A: No. The FR-D740 series supports sensorless vector control only — it does not have an encoder input and cannot perform closed-loop vector (flux vector) operation. For encoder-based closed-loop vector control at this power rating, the FR-A740-120-NA is the appropriate selection.
Q: Is an external braking resistor required for the FR-D740-120-NA?
A: The drive includes a built-in brake transistor, so an external braking resistor can be connected directly to the P/+ and PR terminals. However, no resistor is included as standard — it must be ordered separately based on the required braking duty cycle. For continuous or frequent regenerative braking, calculate the resistor rating using Mitsubishi’s FR-D700 instruction manual braking resistor selection tables.
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