Mitsubishi FR-A840-18.5K High-Performance Inverter

FR：Inverter

A：A800 high-performance series

8：8th generation

4：3-phase 400V class (380～500V)

0：Standard open type, IP20

18.5K：ND rated applicable motor power 18.5kW

-1：Japanese domestic specification (corresponding China domestic model: FR-A840-00470-2-60)

Core Electrical Specifications

Input: 3-phase AC380～500V, 50/60Hz

ND (Normal duty, factory default): For 18.5kW motor, rated output current 38A, 150% overload for 60s

LD (Light duty): Drives up to 22kW, rated current 43A; SLD super light duty max 47A

HD Heavy duty mode: For 15kW motor, 31A, 180% overload for 60s (selected for cranes, extruders and other high-shock loads)

Output frequency: 0.2～590Hz; max 400Hz under vector control

Built-in braking transistor (18.5kW model includes built-in braking transistor, external braking resistor connectable)

Protection class: IP20 (cabinet mounting)

Control Performance

1. Sensorless vector control: High low-speed torque, 200% torque output at 0.5Hz; supports asynchronous motor + PM permanent magnet synchronous motor drive, motor auto-tuning
2. V/F control, advanced magnetic flux vector; closed-loop vector available with encoder option card FR-A8AP
3. Built-in simple PLC (sequence operation function), capable of simple logic programming to reduce external PLC I/O points
4. Speed response up to 50Hz, suitable for high-precision tension, spindle, winding and positioning applications

Communication & Expansion

Standard RS485 (Modbus RTU)

Optional communication cards: CC-Link, CC-Link IE Field, Profinet, Profibus-DP, DeviceNet, etc.

Terminals: Digital inputs, relay outputs, open-collector outputs, AM analog voltage monitor, CA analog current monitor

Options: Operation panel, braking resistor FR-ABR, EMC filter, DC reactor, encoder interface card

Typical Application Scenarios (High Search Keywords)

Spindle drive, crane, winch, extruder, centrifuge, fan & water pump, belt conveyor, tension control, packaging machinery, air compressor. The A800 series is positioned as a high-performance heavy-duty general inverter, superior to F800 for loads requiring fast dynamic response.

Environmental Specifications

Operating temperature: -10℃～+50℃ (no icing); SLD mode upper limit +40℃

Storage temperature: -20℃～+65℃

Humidity: Max 95%RH, non-condensing; altitude ≤1000m (derating required above 1000m)

Replacement & Migration Notes

1. Legacy model replacement: FR-A740-18.5K upgraded to this model; mounting dimensions and terminal definitions differ, parameters cannot be copied directly and motor auto-tuning must be re-performed
2. Japanese `-1` vs domestic `-2-60`: Same hardware core, different firmware/standards, nameplate and factory preset parameters. Cannot be interchanged for procurement; region code must be distinguished during ordering
3. Domestic alternative reference: Inovance MD880, Infineon platform high-performance inverters

Quick Reference for Common Faults

E.OC1: Overcurrent during acceleration; E.OC2: Overcurrent at constant speed; E.OC3: Overcurrent during deceleration

E.OV: DC bus overvoltage (high inertia loads require braking resistor)

E.THT: Inverter heatsink overheat (fan failure, blocked cooling duct)

E.THM: Motor electronic thermal overload

Selection Tips

Shock loads & frequent start-stop → Use HD mode, it is recommended to select one higher capacity grade

Stable loads such as fans and pumps → Use LD/SLD for higher available motor power

High inertia shutdown → Braking resistor mandatory; 18.5kW unit has built-in braking transistor, no separate braking unit needed

Application Fields of Mitsubishi FR-A840-18.5K-1 (A800 18.5kW 400V Class)

The FR-A840 is a high-performance heavy-duty vector inverter. Featuring high low-speed torque, fast response, support for torque/tension control and built-in braking transistor, it is ideal for heavy impact, tension control, spindle and lifting applications, and also supports energy-saving retrofit for fans and pumps.

1. Crane & Lifting Equipment (HD Heavy Duty Mode Preferred)

Gantry crane, overhead crane, small winch, AS/RS stacker, hoist

Features: High low-speed torque, anti-sway control, load holding for heavy weights, high inertia load, frequent start-stop; 18.5kW built-in braking transistor realizes fast braking with braking resistor

Application keywords: Crane, winch, stacker, lifting, anti-sway

2. Web Tension Control Industry (Winding & Unwinding)

Paper making, film, non-woven fabric, adhesive tape, wire & cable drawing, printing machine, slitter

Supports sensorless tension control, dancer roller feedback, line speed synchronization, reduces web tension fluctuation and ensures uniform winding quality

Application keywords: Winding, unwinding, slitting, coating, wire drawing, printing, tension control

3. Machine Tool & Processing Equipment

CNC machine spindle, grinder, milling machine, stone cutting machine, engraving machine

Wide speed range, fast response, supports asynchronous and PM motor drive; closed-loop vector available with FR-A8AP encoder card for high-precision spindle speed regulation

Application keywords: Machine spindle, grinding machine, high-speed cutting

4. Extrusion & Rubber/Plastics Machinery

Plastic extruder, rubber extruder, pelletizer, internal mixer

Large load fluctuation, high starting torque requirement, stable screw speed control to stabilize extrusion pressure and improve product consistency

5. Conveying & Logistics Automation

Belt conveyor, roller conveyor, automated warehouse, sorting line, heavy-duty pallet conveyor

Multi-drive synchronous control, soft start to reduce mechanical shock; supports PM permanent magnet motor energy-saving solution

Application keywords: Heavy-duty conveyor, roller line, logistics sorting

6. General Fluid Equipment (Energy-saving Retrofit, LD/SLD Light Duty Mode)

Large fan, process water pump, air compressor, central air conditioning circulating pump

PID constant pressure/flow control, optimized excitation for energy saving; suitable for energy-saving retrofit of constant torque / variable torque loads

Note: F800 series is preferred for fans and pumps; A800 advantage is versatile capability for heavy-duty applications

7. Other Heavy Industry Applications

Press machine, auxiliary drive for shield machine, mixer, centrifuge, marine deck auxiliary machinery (with filter to meet class society certification)

Heavy-duty host for food packaging, large mixing equipment

Selection & Application Key Points

1. Shock loads, lifting, extrusion, winding: HD heavy duty mode, 180% overload for 60s
2. Stable fan/pump loads: LD/SLD light duty mode for energy saving priority
3. High inertia shutdown (winch, winding): External braking resistor required, braking transistor built-in
4. Japanese FR-A840-18.5K-1 shares identical hardware with China domestic model but differs in factory preset parameters and standards; distinguish region version for project selection.
5. FR-A840 (3-phase 400V, Japanese domestic suffix -1, FR-A840-18.5K-1 listed here)

Power Model List (ND rated motor power)

1. FR-A840-0.4K-1
2. FR-A840-0.75K-1
3. FR-A840-1.5K-1
4. FR-A840-2.2K-1
5. FR-A840-3.7K-1
6. FR-A840-5.5K-1
7. FR-A840-7.5K-1
8. FR-A840-11K-1
9. FR-A840-15K-1
10. FR-A840-18.5K-1 (Your model)
11. FR-A840-22K-1
12. FR-A840-30K-1
13. FR-A840-37K-1
14. FR-A840-45K-1
15. FR-A840-55K-1
16. FR-A840-75K-1
17. FR-A840-90K-1
18. FR-A840-110K-1
19. FR-A840-132K-1
20. FR-A840-160K-1
21. FR-A840-185K-1
22. FR-A840-220K-1
23. FR-A840-250K-1
24. FR-A840-280K-1

Corresponding China Domestic Models (Suffix -2-60, current code type)

1. Other A800 Series Models (Full Product Line)
2. FR-A820 (3-phase 200V class): 0.4K～90K, suffix -1 (Japanese) / -2-60 (China)
3. FR-A840 (3-phase 400V, main model as listed above): 0.4K～280K
4. FR-A842 (High power split type, 400V): 315K～500K (separate rectifier + inverter unit)
5. FR-A846 (Dust-proof 400V): 0.4K～132K, enhanced cabinet dust resistance
6. FR-A840M (Module type 400V): 160K, 200K, common DC bus dedicated
7. Derivative suffixes:

E: Global general version

GF: Built-in CC-Link IE Field

GN: Built-in CC-Link

CRN: Class certified marine model

III. Key Notes

1. Suffix explanation: -1 = Japanese domestic unit; -2-60 = China mainland unit. Hardware identical, factory parameters and safety standards differ; cannot be directly interchanged for purchase.
2. Models 18.5kW and below have built-in braking transistor; 22kW and above high power models require separate braking unit.
3. HD mode for heavy-duty applications; LD/SLD light duty for fans & pumps with derating operation.

Mitsubishi FR-A840-18.5K-1 Installation & Commissioning Full Tutorial

Model description: FR-A840-18.5K-1, 3-phase 400V, 18.5kW, built-in braking transistor (P/+, PR terminals for braking resistor); Japanese version, hardware identical to China FR-A840-00470-2-60, different factory default parameters.

⚠️ Safety Precaution: All wiring work must be performed with power off; capacitors retain high voltage after main power cut-off. Wait at least 10 minutes and confirm charge lamp is OFF before opening cover.

1. Mechanical Installation (Cabinet Mounting IP20)
2. Installation Environmental Requirements

Mounting orientation: Vertical wall mount, horizontal or inverted mounting prohibited; fixed on non-combustible rigid steel plate

Ambient temperature: Operation -10℃～+50℃ (no icing); SLD light duty ≤40℃; cabinet ventilation required

Environment: Keep away from dust, oil mist, corrosive gas, direct sunlight; humidity ≤95%RH non-condensing; altitude ≤1000m, derating required above 1000m

Cabinet clearance: ≥100mm free space top & bottom for heat dissipation; multiple units can be mounted side-by-side at ambient temperature, ≥50mm gap recommended for high-temperature environments

2. Installation Steps
3. Unpacking inspection: Check housing integrity, fan intact, operation panel and terminal cover complete; verify nameplate model FR-A840-18.5K-1
4. Position and drill holes, fasten with M6/M8 screws, tighten torque per manual to prevent vibration loosening
5. Remove front cover for main circuit and control circuit wiring; reinstall cover after wiring completion
6. Install optional parts (if required): braking resistor, EMC filter, DC reactor, FR-A8AP encoder card (for closed-loop vector)
7. Electrical Wiring (Key Terminals)

Main Circuit Terminals

R/L1, S/L2, T/L3: 3-phase 380～500V power input

U, V, W: Connect to 3-phase asynchronous motor; Do NOT install capacitor or surge absorber on inverter output side; this will damage inverter

P/+, PR: Braking resistor terminals (built-in braking transistor); remove PR-PX jumper before connecting braking resistor; braking resistor mandatory for winch, winding and high inertia loads

Ground terminal: Reliable earth connection required, earth resistance ≤10Ω; separate grounding for inverter and motor to reduce interference

Control Circuit Terminals (Commonly Used)

STF: Forward run; STR: Reverse run; SD: Digital input common terminal (sink type default)

RH/RM/RL: Multi-speed terminals

AU: Current input selection; Terminal 4: 4～20mA; Terminal 2: 0～10V voltage reference

AM: Analog voltage monitor; CA: Analog current monitor

A/B/C: Fault relay output (B-C closed, A-C open during fault)

Wiring specification: Main power cable recommended 10mm²; shielded motor cable preferred; separate routing for power cable and control cable; shielded control cable with single-end grounding.

III. Pre-power-on Inspection (Mandatory to Prevent Damage)

1. Use multimeter in power-off state: No short circuit between R/S/T, U/V/W; no short circuit between P/+ and PR; no short circuit to ground
2. Confirm motor wiring correct, mechanical load decoupled (Decouple mechanical load for first trial run, test motor without load)
3. Verify braking resistor wiring without short circuit; all terminal screws tightened
4. Confirm input power AC380～480V, no overvoltage
5. Power On & Basic Parameter Setting (PU Panel Commissioning)

Panel keys: MODE, SET confirm, ESC exit, PU/EXT toggle, knob adjustment; PU = panel control; EXT = external terminal control

Step1: Power on, parameter reset (optional for new unit; recommended for used unit or motor replacement)

Enter parameter, set Pr.ALLC=1 for all parameter clear; power cycle to restore factory settings

Step2: Basic motor nameplate parameters (Core for vector control, must be filled)

Step3: Operation Mode Pr.79 (Most common)

Pr.79=0: PU/EXT switchable (factory default)

Pr.79=1: PU panel mode, start/stop and frequency set via panel, for commissioning

Pr.79=2: External terminal mode, STF/STR start-stop, potentiometer /4-20mA frequency reference, normal field operation

Pr.79=3: Terminal start, panel knob frequency setting (combined mode)

Step4: Control Mode Selection (A800 core)

Pr.800=0: V/F control (fans, pumps, simple conveyor)

Pr.800=20: Sensorless vector control (asynchronous motor), recommended for crane, extruder, winding, high low-speed torque

Pr.800=30: Closed-loop vector (FR-A8AP encoder card required for motor with encoder)

Step5: Acceleration / Deceleration, Frequency Limit

Pr.0: Torque boost; normally not increased under vector control

Pr.1: Upper frequency limit; Pr.2: Lower frequency limit

Pr.7: Acceleration time; Pr.8: Deceleration time; extend deceleration time for high inertia loads and use braking resistor

1. Motor Auto-Tuning (Mandatory for Vector Control, Critical Step)

Two auto-tuning types: Static auto-tuning (motor stationary) and Rotational auto-tuning (motor rotating, higher accuracy)

✅ Recommended: Perform Rotational auto-tuning with load decoupled

1. Set Pr.96=11 (Rotational auto-tuning for asynchronous motor), press SET
2. Panel shows “READY”, press FWD start, inverter excites motor automatically, motor runs at low speed
3. Process lasts dozens of seconds, panel displays END after completion → auto-tuning successful
4. If ERR displayed: Check motor wiring, nameplate parameters, motor jamming, re-run auto-tuning

Static auto-tuning (when load cannot be decoupled): Pr.96=10; accuracy lower than rotational tuning

1. No-load Trial Run (PU Mode)
2. Pr.79=1, PU mode, confirm mechanical no-load, personnel keep clear of transmission mechanism
3. Set target frequency (e.g.10Hz), press FWD forward run
4. Monitor: Motor rotation direction, current, vibration, noise; check output frequency & current on panel
5. Reverse test: REV; stop by STOP
6. Wrong rotation direction: Power off and swap U & V motor leads; Do NOT swap input R/S/T

Normal no-load current is 30%～60% of motor rated current; stop immediately if abnormal current occurs

VII. Loaded Commissioning (Switch to External Mode)

1. Wire external terminals: STF-SD (forward switch), potentiometer to Terminal2 & 5 for 0~10V frequency reference
2. Pr.79=2, switch to EXT external mode
3. Low frequency trial run (5~10Hz) under load, monitor torque, current and alarms
4. Gradually increase frequency and observe:

Heavy-duty applications (winch, extruder): Enable HD heavy duty mode, 180% overload 60s

Fans & pumps: LD/SLD light duty mode

5. Tune acceleration/deceleration time and braking duty ratio; fine-tune tension parameters for tension control applications

VIII. Communication Commissioning (RS485/CC-Link/Profinet, Optional)

1. Built-in RS485: Modbus RTU, set station address, baud rate, parity bit
2. Communication option cards (FR-A8NP Profinet, FR-A8NC CC-Link): Install when power off, configure parameters, communication address and parameter mapping
3. Common Commissioning Alarm Troubleshooting

E.OC1: Overcurrent during acceleration; motor short circuit, mechanical jam, too short acceleration time

E.OV: DC bus overvoltage; high inertia shutdown, increase braking resistor capacity or extend deceleration time

E.THT: Inverter overheat; fan damage, blocked cooling air duct

E.UVT: Undervoltage; input phase loss, large voltage drop

E.ALM: Motor overload; incorrect Pr.9 thermal setting, mechanical binding

1. Handover & Documentation
2. Upload parameters to operation panel for backup (parameter copy), save parameter document
3. Record auto-tuning result, motor parameters and alarm history
4. Retighten all terminals, reinstall cover, clean cabinet debris

Important Notes

1. Japanese FR-A840-18.5K-1 has different safety specs and factory preset settings vs China -2-60 model. Do not directly download Chinese project parameter files; re-run motor auto-tuning.
2. 18.5kW unit has built-in braking transistor, but braking resistor needs separate selection, cannot be omitted.
3. Motor auto-tuning is mandatory for vector control, otherwise low-speed torque is insufficient and trip may occur.