MITSUBISHI ELECTRIC FR-D700 Inverter Complete Guide

Excellent motor control performance

4.1 General Magnetic Flux Vector Control

FR-D700 adopts universal flux vector control, which significantly improves low-speed torque compared to traditional V/f control. Specific indicators:

150% torque @ 1Hz (3.7kW and below)

200% torque @ 3Hz (3.7kW and below)

Built in self-tuning function, which can automatically measure parameters such as the primary resistance (R1) of the motor, optimizing the control effect. Self tuning can be completed without the motor rotating (only static self-tuning), which is very friendly to motors already installed on the equipment.

Applicable scenarios: loads that require high starting torque, such as conveyor belts, elevators, washing machines, mixers, etc. For square torque loads such as fans and pumps, energy saving can be achieved through optimal excitation control.

4.2 Optimal excitation control

By automatically adjusting the excitation current, the motor efficiency is maintained at its optimal state, especially suitable for equipment (fans, pumps) where load torque varies with speed. Tested to save about 10-20% of electrical energy under light load.

4.3 Regeneration Avoidance Function

When the motor is dragged beyond the set frequency due to external loads (such as another fan), the frequency converter will automatically increase the output frequency to suppress regenerative energy and reduce the occurrence of overvoltage tripping (E.OV). Very suitable for parallel fan, compressor and other systems.

4.4 Other Practical Functions

Traverse control: used in spinning, drawing and other winding processes to prevent uneven accumulation of yarn or metal wires by periodically changing the frequency. Parameters Pr.592~Pr.597 can be set for swing amplitude, swing period, etc.

PID control: Equipped with a built-in PID regulator, it can be used for constant pressure water supply, constant temperature control, etc., without the need for an external controller.

Power outage deceleration stop function: When the power is cut off or under voltage, the automatic deceleration stops the motor smoothly, avoiding free sliding. It is suitable for situations such as machine tool spindles that require controllable parking.

Dancer control: Constant tension control is achieved by connecting the position signal of the dance roller through analog input.

Selection and Rating Interpretation

5.1 Model Code Description

FR-D720- □ K (three-phase 200V), FR-D740- □ K (three-phase 400V), FR-D720S - □ K (single-phase 200V), FR-D710W - □ K (single-phase 100V). The number inside indicates the applicable motor power (kW). For example, FR-D720-2.2K corresponds to a 2.2kW three-phase 200V frequency converter.

Differences in export specifications: Japanese specifications, North American specifications (NA), European specifications (EC), and Chinese specifications (CHT) differ in terms of main circuit terminal names, initial control logic settings (drain/source), and initial parameter values (such as fundamental frequency 60Hz vs 50Hz). When selecting, it is important to confirm the certification requirements of the target market (UL, CE, KC, EAC, etc.).

5.2 Current and Overload Capacity

Taking FR-D720-2.2K as an example:

Rated output current: 10.0A (corresponding to 2.2kW)

Overload capacity: 150% 60 seconds, 200% 0.5 seconds (inverse time characteristic)

Applicable motor: Standard Mitsubishi 4-pole motor

Selection trap: If the rated current of the motor is greater than the rated output current of the frequency converter, even if the power is matched, it may not be able to operate at full load for a long time. For heavy-duty applications such as reciprocating compressors and frequent start stop, a higher capacity should be selected and a longer acceleration and deceleration time should be set.

5.3 Braking Capacity

Built in braking transistor (0.4K and above), can be directly connected to external braking resistors (MMS/MYS type or high load FR-ABR). Braking torque:

0.1K~0.2K: 150% (without built-in brake transistor, no resistor can be added)

0.4K：150%

0.75K：100%

1.5K~2.2K：50%

3.7K and above: 20% (braking only based on motor loss)

Important: When using a braking resistor, Pr.70 (special regenerative braking duty cycle) and Pr.30 (regenerative function selection) must be set correctly, otherwise the resistor may overheat and be damaged. For frequent braking or high inertia loads, it is recommended to use FR-BU2 braking units or FR-CV regenerative rectifiers.

Communication and Programming: Flexible Integration Capability

6.1 Built in RS-485 communication

FR-D700 comes standard with an RJ45 interface (PU interface) and supports:

Mitsubishi inverter protocol (computer link communication): up to 32 stations can be set, with a maximum communication speed of 38400bps. Added 'multi command mode', reducing data processing time to 1/4 of the original.

Modbus RTU protocol: can be directly connected to common SCADA or PLC (such as Mitsubishi FX series). Register addresses are mapped to Modbus standards, making configuration simple.

Wiring and configuration:

Using shielded twisted pair cables, the terminal resistance should be set at both ends (SW2 switch).