Mitsubishi FR-F800 for pumps and fans: selection, energy saving, parameters
FR-F800 is a Mitsubishi Electric drive series built specifically for pumps and fans: a square-law U/f characteristic, a PID controller, sleep mode, multi-pump control and a cleaning mode. The manual (art. 292984, version B, 840 pages) covers FR-F820 for 0.75-110 kW, FR-F840 for 0.75-315 kW and FR-F842 for 355-560 kW. Below: how to pick a model, which parameters handle savings and pressure control, and how the FR-F800 differs from the general-purpose FR-A800.
All figures come from the Russian-language manual: FR-F800_manual_ru.pdf. There is also a short installation guide (56 pages) and a beginner's guide (120 pages). Factory values of some parameters depend on the output type (FM or CA), and we say so wherever it applies.
| Branch | Range per the manual |
|---|---|
| FR-F820 (200 V class) | FR-F820-00046(0.75K) ... 04750(110K) |
| FR-F840 (400 V class) | FR-F840-00023(0.75K) ... 06830(315K) |
| FR-F842 | FR-F842-07700(355K) ... 12120(560K) |
FR-F840 models are in the FR-F section; the whole brand is on the Mitsubishi Electric variable frequency drives page.
How FR-F800 differs from FR-A800 and how to choose a model
In the model code the current figure (00023…12120) is the SLD-class rated current in both series, while the kW in brackets is referenced to different classes: ND on the FR-A800 and LD on the FR-F800. So compare models by model code and current, not by kW alone.
- Power numbering is shifted. FR-F820-00770 is 18.5 kW, whereas FR-A820-00770 is 15 kW. Compare by model code and current.
- No built-in brake circuit. Terminals PR and PX must not be used; the manual states this directly.
- Two overload classes (Pr.570): SLD (0) and LD (1), no ND or HD. By default Pr.570 = 1 (LD) for FM type and 0 (SLD) for CA type.
- Square-law U/f by default (Pr.14 = 1), i.e. for torque that grows with the square of speed.
| Pr.570 | Class | Overload | Temperature |
|---|---|---|---|
| 0 | SLD | 110% 60 s, 120% 3 s | 40 C |
| 1 | LD | 120% 60 s, 150% 3 s | 50 C |
Changing Pr.570 changes the factory values of Pr.9, 22, 48, 56, 148, 149, 150, 165, 557, 874, 893. So set the class first. With SLD the carrier frequency is reduced as load grows; this is also stated in the manual.
Choosing the characteristic: Pr.14
For a fan or a typical centrifugal pump with a square-law load keep Pr.14 = 1 (square-law torque). For FR-F820-01540(37K) and above and FR-F840-00770(37K) and above the manual notes that voltage rises with a power of 1.75 rather than 2. Set 0 (constant torque), even for a pump or a fan, in three cases: a blower with high inertia that must accelerate quickly; a constant-torque load (the manual explicitly names a centrifugal pump and a transmission pump here); a load whose torque rises at low speed, such as a screw pump.
FR-F800 power terminals
Mains on R/L1, S/L2, T/L3, motor on U, V, W, as on the FR-A800; the differences are in braking and the reactor.
| Terminal | Purpose |
|---|---|
| R/L1, S/L2, T/L3 | Mains |
| U, V, W | Motor |
| R1/L11, S1/L21 | Separate control power. 60 VA for FR-F820-00630(15K) and smaller and FR-F840-00380(18.5K) and smaller, 80 VA for larger models |
| P/+, N/- | Brake unit, FR-CV, MT-RC, FR-HC2 or DC supply |
| P3, N/- | In parallel with P/+, N/-: use either P/+ or P3. A DC supply goes to P/+ and N/-, not to P3 |
| P/+, P1 | FR-HEL DC reactor. Remove the jumper for FR-F820-02330(55K) and smaller and FR-F840-01160(55K) and smaller |
For FR-F820-03160(75K) and above and FR-F840-01800(75K) and above the DC reactor is mandatory. Analog control needs the same matching as on the FR-A800: the "voltage/current" switch for terminals 2 and 4 together with Pr.73 and Pr.267. Terminal 1 is set through Pr.868. The FR-F800 control terminals are described in chapter 2 of its manual; for comparison, the FR-A800 control terminals are covered in FR-A800: terminals, parameters, fault codes.
Basic parameters for start-up
| Pr. | Name | Factory value | Range |
|---|---|---|---|
| 0 | Torque boost | depends on capacity: 6%, 4%, 3%, 2%, 1.5%, 1% | 0-30% |
| 1 | Maximum frequency | 120 Hz (up to 55 kW), 60 Hz (75 kW and above) | 0-120 Hz |
| 2 | Minimum frequency | 0 Hz | 0-120 Hz |
| 3 | Base frequency | 60 Hz (FM), 50 Hz (CA) | 0-590 Hz |
| 7 | Acceleration time | 5 s (up to 7.5 kW), 15 s (11 kW and above) | 0-3600 s |
| 8 | Deceleration time | 10 s (up to 7.5 kW), 30 s (11 kW and above) | 0-3600 s |
| 9 | Electronic motor protection current | rated drive current | 0-500 A or 0-3600 A |
| 14 | Load characteristic | 1 (square-law) | 0, 1 |
| 60 | Energy saving function | 0 | 0, 4, 9 |
Energy saving: Pr.60, Pr.248, Pr.254
The FR-F800 saves energy in two ways: automatic motor voltage reduction (Pr.60) and switching off the power circuit at standstill (Pr.248, Pr.254). The manual promises no specific percentages, so we give none either.
- Pr.60 = 4 - energy saving mode. If the motor runs at a constant frequency for a while, the drive lowers the motor voltage by itself. Works only with U/f control.
- Pr.60 = 9 - optimum excitation control. Reduces consumption and motor losses, especially at light loads. Works with U/f and Advanced magnetic flux vector control.
Limits from the manual: with high load torque or frequent acceleration/deceleration the effect is small; if the motor is much smaller than the drive or several motors share one drive, the effect is weaker; deceleration time may exceed the set value and overvoltage trips become more likely, so lengthen the deceleration time; output current may rise slightly.
Switching off the power circuit at standstill
If the input contactor MC is opened while the motor is stationary, standby consumption drops. Parameters: Pr.248 (0 - disabled; 1 and 2 - enabled, differing in the condition for switching off when a protective function trips), Pr.254 (1-3600 s, default 600 s - the pause between motor stop and power circuit off; 9999 - switch-off only when a protective function trips) and Pr.137 (start delay, default 0.5 s; set slightly longer than the contactor operating time). In this mode the control circuit is powered separately via R1/L11 and S1/L21 or from an external 24 V.
PID pressure control and sleep mode
For the drive to hold pressure or level by itself, enable PID on the FR-F800 and feed the sensor signal to terminal 4. The minimum set per the manual: Pr.128 = 20 (or 21 - they differ in the direction of action) and the X14 signal that enables PID. In the manual's example X14 is assigned to terminal RT with Pr.183 = 14. The AU signal is not needed, and Pr.868 must be 0, otherwise PID is inactive. The setpoint is set with Pr.133 or on terminal 2.
| Pr. | Purpose | Default / range |
|---|---|---|
| 128 | PID input selection and direction of action | 0; 20/21 - sensor on terminal 4 |
| 129 | Proportional band (inverse of gain) | 100%; 0.1-1000% |
| 130 | Integral time | 1 s; 0.1-3600 s |
| 131 / 132 | Upper / lower feedback limit (FUP / FDN outputs) | 9999 - not used |
| 133 | Setpoint from the panel | 9999; 0-100% |
| 575 | Output stop detection time (sleep) | 1 s; 0-3600 s, 9999 |
| 576 | Output stop frequency threshold | 0 Hz; 0-590 Hz |
| 577 | Threshold for returning from sleep to PID | 1000%; 900-1100% |
Lowering Pr.129 improves sensitivity but hurts stability: the system starts to hunt. Lowering Pr.130 gets to the setpoint faster but raises overshoot. Sleep mode (Pr.575 and Pr.576) stops the pump when pressure holds without the motor needing to turn. The manual also has a PID pre-charge mode (Pr.1363, signal Y217) and up to seven setpoints through Pr.1460-Pr.1466.
Multi-pump control
One drive can run a pump plus up to three auxiliary motors via contactors. Pr.578 sets the number of auxiliary motors (0-3, default 0), Pr.579 the method: 0 basic, 1 alternating, 2 direct, 3 alternating-direct. Contactor interlock time is Pr.580 (default 1 s). Start frequencies of auxiliary motors are Pr.584-Pr.586, stop frequencies Pr.587-Pr.589, delays Pr.590 and Pr.591. The function works only while X14 is on.
Cleaning mode
For pumps that clog there is cleaning by reverse rotation. Number of cycles is Pr.1470 (0-255; 0 disables the function), reverse frequency Pr.1472 (default 30 Hz), pause Pr.1476 (5 s), automatic cleaning interval Pr.1479 (0.1-6000 h, 0 disabled). The cycle counter is Pr.1469, activity is signaled by X98. The first cycle runs in the direction opposite to the start command.
FR-F800 fault codes
Fault names are the same as on the FR-A800, but thresholds and sensitivity can differ. Full tables are in chapter 6 of the FR-F800 manual; below is what we checked for this series specifically.
| Display | Meaning | Per the FR-F800 manual |
|---|---|---|
| E.OC1, E.OC2, E.OC3 | Overcurrent | Trips at approx. 170% (LD) or 148% (SLD) of rated current |
| E.THT | Drive overload | Sensitivity 120% for 60 s (150% on the FR-A800). Check acceleration/deceleration time, torque boost and whether the selected characteristic suits the load |
| E.IPF | Power failure | Mains lost for more than 15 ms |
| E.UVT | Undervoltage | Below 150 V (200 V class) or 300 V (400 V class) |
The full list of faults and remedies is in chapter 6 of the FR-F800 manual. The main fault names match the FR-A800 (see the FR-A800 article), but check thresholds against the table above. For D700/E700 there is a separate article on fault codes.
Further reading
- PID and sleep setup on entry-level series: PID and sleep mode on Mitsubishi.
- General overview: next-generation drives for pumps and fans. We do not repeat the savings figures from that article.
- Braking resistor: how it works.
- Brand comparison: Siemens and Mitsubishi.
Series and models: FR-F and Mitsubishi Electric. If you want a second opinion on choosing a model for a pump, send the motor rating plate, the load type and the supply voltage.
Choosing an FR-F800 in the catalog
In the catalog the F800 generation is listed as FR-F840-xxxxx-E2-60 part numbers: the list with availability is on the FR-F series page, which also shows the earlier FR-F740 and FR-F746. FR-F842 (355–560 kW) is supplied to order. For a pump station we select the drive by motor current and load type, and can offer a ready-made pump control cabinet. Send the motor nameplate, load type and supply voltage — contact an engineer or browse all Mitsubishi Electric drives.
