MITSUBISHI ELECTRIC FR-A500 Series Inverter Manual

Product and Safety Overview

Product range:

Model: FR-A520 (200V), FR-A540 (400V)

Power: 0.4K~55K (kW)

Type: Transistor inverter, focusing on high functionality and low noise

Security level (must be followed):

Warning: Incorrect operation may result in death/serious injury

It is strictly prohibited to open the front cover when powered on/running

Wait for ≥ 10 minutes after power failure and confirm that there is no residual voltage

Must be grounded (PE) in accordance with IEC 60364, NEC 250

CAUTION: Incorrect operation may cause injury/damage to equipment

Installed on non combustible materials

It is strictly prohibited to connect power factor capacitors, surge absorbers, and filters on the output side

The main power contactor cannot be used for frequent start stop operations

Installation and environmental requirements

Project specifications

Constant torque at ambient temperature: -10~+50 ℃; Variable torque: -10~+40 ℃

Humidity ≤ 90% RH (non condensing)

Vibration ≤ 5.9m/s ²

The installation direction must be vertical, with a ventilation distance of ≥ 5cm/10cm above and below

Installation inside the protective cabinet to prevent oil mist, dust, and water droplets

Installation points:

Grasp the body, do not grip the front cover

Foreign objects must not fall into the machine

Multiple units installed side by side need to ensure proper ventilation ducts for heat dissipation

Wiring (Core)

1. Main circuit terminal

Key requirements for terminal function

R/S/T three-phase power input must not be connected to U/V/W

U/V/W frequency converter output → It is strictly prohibited to connect capacitors/filters to the motor

R1/S1 control circuit power supply can independently supply power and maintain alarm output

P-PR brake resistor connected to 7.5K or below with built-in brake

Remove the jumper and reconnect the P-P1 DC reactor connection

Grounding body grounding thick wire, short distance, independent grounding

2. Control circuit terminals (commonly used)

Terminal function

STF forward rotation start

STR Reverse Start

RES reset (effective for ≥ 0.1s)

AU current input (4-20mA) is valid

RH/RM/RL multi-stage speed selection

A/B/C alarm relay output

FM/AM frequency/analog meter output

Wiring taboos:

Separate wiring for the main circuit and control circuit, using shielded twisted pair cables for control

The total length of the output line is ≤ 500m, and the carrier frequency needs to be reduced for long distances

Operation and Running Mode

Operation panel: FR-DU04

Buttons: MODE switch mode, SET confirm, FWD/REV forward and reverse, STOP/RESET stop reset

Display: Frequency/Current/Voltage/Alarm

4 operating modes (Pr.79 setting):

External mode (default): Terminal control start stop+analog/multi-stage speed setting

PU mode: direct panel operation

Combination mode: external start stop+PU frequency or PU start stop+external frequency

Communication mode: RS485 controlled by the upper computer

Basic operation process: Wiring check → Power on → Confirm EXT/PU indicator light → Set frequency → Start → Monitor → Stop

Parameter system (core)

Required basic parameters

Parameter Number Name Typical Value/Range Description

Pr.0 torque increase 0-30% low-frequency torque compensation

Pr.1 Maximum frequency 0~120Hz output upper limit

Pr.2 Minimum frequency 0~120Hz output lower limit

Pr.3 Base frequency 50/60Hz motor rated frequency

Pr.7 acceleration time 0~3600s 0 → 60Hz time

Pr.8 deceleration time 0~3600s 60 → 0Hz time

Pr.9 electronic overcurrent relay motor rated current motor thermal protection

Pr.79 operation mode selection 0~8 external/PU/combination

Advanced functional parameters

Multispeed: Pr.4-6, Pr.24-27, Pr.232-239 (up to 15 speeds)

PID control: Pr.128-134 (proportional/integral/derivative)

Instant power outage restart: Pr.57, Pr.58, Pr.162

Vector control: Pr.80~96 (motor capacity, number of poles, automatic tuning)

Frequency jump: Pr.31-36 (avoid mechanical resonance)

Parameter protection: Pr.77 (0=shutdown writable, 1=prohibit writing, 2=run writable)

Protection function and alarm

Typical protection projects:

Overcurrent E.OC1-3

Overvoltage E.OV1-3

Undervoltage E.UVT

Overload E.OL

Overheated E.OH

Output phase loss, CPU failure, communication abnormality

Fault handling:

After alarm: investigate the cause → reset RES terminal or panel → restart operation

Retry function (Pr.65-69): Automatically retry after alarm, up to 10 times

Maintenance and repair

Daily inspection:

Cooling fan, abnormal heating, peculiar smell, abnormal noise, loose terminals

Regular inspection:

Main circuit voltage, insulation, capacitor lifespan, and cleaning of heat sinks

Prohibited items:

Do not perform megohmmeter (shake meter) testing on the control circuit

Lifespan components:

Cooling fan, electrolytic capacitor (Pr.504 set alarm time)

Specifications and Options

standard specifications

Input: Three phase 200V/400V, 50/60Hz

Control mode: PWM control, Soft PWM low noise

Carrier frequency: 0.7~14.5kHz (Pr.72)

Overload capacity: 150% for 1 minute

Common options

FR-ABR braking resistor

FR-BAL/FR-BEL Reactor

FR-BIF noise filter

FR-A5NR communication module

Key issues (3 different focuses)

Question 1: Why is it strictly prohibited to connect capacitors, surge absorbers, or filters on the output side (U/V/W) of the frequency converter?

answer:

The output of the frequency converter is high-speed PWM pulses, containing a large amount of high-frequency harmonics;

Capacitors can form high current charging and discharging circuits, directly causing overcurrent tripping (E.OC) of the frequency converter and even burning of the power module;

Surge absorbers/filters can resonate with output harmonics, causing overheating, damage, and false protection;

Specification: Filters and reactors can only be installed on the input side (R/S/T).

Question 2: What is the function of Pr.79 operating mode? What control methods correspond to commonly used settings?

Answer: Pr.79 is used to switch between start stop and frequency given sources, and is the most commonly used parameter for on-site debugging:

0: Switching mode when power is turned on (EXT/PU)

1: PU mode (panel operation only, safest)

2: External mode (terminal start stop+external simulation/multi-stage speed, factory default)

3: Combination mode (external start stop, PU set frequency)

4: Combination mode (PU start stop, external frequency setting)

5-8: Communication/Fixed Mode, etc

Question 3: What are the three most common reasons and troubleshooting steps for the motor not rotating and the panel not sounding an alarm?

answer:

Operation mode mismatch

EXT lights up but starts with the panel/PU lights up but starts with the terminal → switch to Pr.79 mode.

Start/frequency signal not effectively inputted

External mode: STF/STR not conducting, frequency set to 0V, AU not turned on (4-20mA).

Protect or restrict actions

The startup frequency Pr.13 is too high, the lowest frequency Pr.2 is 0 but insufficient, and the MRS output stop signal is valid.

Troubleshooting sequence: Confirm mode → Check indicator light → Check terminal voltage → Check parameter limits.