Mitsubishi FR-A500 Series of General Purpose Inverter Repair Experts

Here at Precision Zone, one of our specialties is the repair services of Mitsubishi Inverter drive units. One series that we often work on is the Freqrol-A520/A540 series.

FR-A520/A540 inverters are offered in sizes ranging from 400W up to 55kW and have the option to use three-phase 200V or 400V input power. There are also country codes which designate the unit meeting U.S. specifications or European specifications, denoted by a “-NA” for U.S. or a “-EC” for European at the end of the unit’s model number.

There is an optional parameter unit, FR-PU04, which can be installed directly onto the unit or used remotely using an optional cable. This allows for easy access to parameters as well as monitoring faults. This series offers quite a few different stand-alone option units as well and this can range from external braking resistors to an optional power factor improving DC reactor. Please reference this excerpt from the manual for additional information on these optional units as well as common ways to connect them.

When assessing the functionality of a Mitsubishi General Purpose Inverter, our expert repair team of engineers and technicians conducts a four-step check:

    1. Visual Overview Check
    2. Static Test
    3. Checks Under Power
    4. Alarm Codes Verification

This overview is Precision Zone’s basic troubleshooting process. Once our repair team starts on the job, we use specialized and customized testing fixtures, Huntron trackers, signal generators, oscilloscopes, milli and megaohm meters, as well as any other necessary tools we have available to assure quality repair work. Most importantly, every repair is fully tested in our custom-built simulators under load with a motor to replicate real-life working environment.

Precision Zone goes as far as using heating chambers and overnight dynamic testing, when applicable, to guarantee performance of the repaired product when it arrives back with the customer.

Repair Process for Mitsubishi FR-A520/A540 General Purpose Inverter Drives

Visual Overview

When conducting a visual check, the technician inspects the drive for any mechanical damage to the drive itself and any printed circuit boards (PCB). The technician then proceeds to verify connections are tight and correct inside the drive and there are no loose screws, wires or debris. Additionally, the unit is checked for any burn marks on the components, PCBs or chassis. During the visual inspection, excessive dirt on cooling components is noted as well as the functionality of the heat sink.

Basic Static Check

Input Module Testing

The input modules on these units can be tested by use of a digital multimeter with diode checking capabilities. Upon removing the cover, all of these terminals can be located along the terminal strip found within the unit.

Positive Lead Negative Lead Reading
R/L1 'P/+' Terminal 0.42V-.52V
S/L2 'P/+' Terminal 0.42V-0.52V
T/L3 'P/+' Terminal 0.42V-0.52V
'N/-' Terminal R/L1 0.42V-0.52V
'N/-' Terminal S/L2 0.42V-0.52V
'N/-' Terminal T/L3 0.42V-0.52V

Output Module Testing

Using the same type of test as above, the output modules can be checked as well. These readings will vary slightly with drive capacity, but each reading should be within 10% of one another. Our technicians are also equipped with huntron devices further verify their integrity.

Positive Lead Negative Lead Reading
U 'P/+' Terminal 0.35V-0.55V
V 'P/+' Terminal 0.35V-0.55V
W 'P/+' Terminal 0.35V-0.55V
'N/-' Terminal U 0.35V-0.55V
'N/-' Terminal V 0.35V-0.55V
'N/-' Terminal W 0.35V-0.55V

Common Alarms for the Mitsubishi FR-A520 and FR-A540

Alarm Code Description Checks
Overcurrent detected during acceleration (E.OC1), constant speed (E.OC2), or deceleration (E.OC3)
  • Check cables for poor insulation
  • Perform magaohm test on motor
  • Use 'Output Module Testing' test to verify modules
  • Check for ground faults
ERR Operation setting error, reset signal ‘ON’, parameter unit not connected properly, high input voltage, faulty internal circuitry
  • Verify operation method
  • Verify proper wiring
  • Check input voltage
  • Swap drive out with another, if applicable
FN The cooling fan within the inverter has stopped functioning
  • Check for any debris lodged within fan fins
  • Verify wiring
  • Replace fan
GF Ground fault has occured on the output of unit
  • Check motor or wire for ground fault
  • Check input/output terminals to ground for leakage
  • Replace Drive

For a full list of Mistubishi FR-A520/A540 alarms from the manual:

The list of alarms within the manual is a good starting point for troubleshooting the Mitsubishi General Purpose Inverters. If any additional troubleshooting assistance is needed for the FR-A520 or FR-A540, Precision Zone offers free technical support. Feel free to contact us via phone or email to get in touch with our experienced technical support team.

Learn the benefit of repairing your Mitsubishi FR-A500 of General Purpose Inverters with Precision Zone

  • Quick and Flexible Service
  • Fully Refurbished, not just repaired
  • Decades of Industry Experience/li>
  • Superior Technology Knowledge and Support

Contact Us To Start Your Repair Today!

Recently Repaired Products

Mitsubishi FR-A520-7.5K-NA image FR-A520-7.5K-NA is an
Inverter-General Purpose manufactured by Mitsubishi
Discovered issues: Bad Capacitor(s), Bad Cooling Fans, Bad Gate Section/Board, Bad Output Transistors/SCRs, Bad Power Section/Board, Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces), Physical Damage to the Drive
Series: FR-A520; 200V
Capacity: 7.5kW; 10 HP
Version: U.S. specification

Mitsubishi FR-A540-7.5K image FR-A540-7.5K is an
Inverter-General Purpose manufactured by Mitsubishi
Discovered issues: Leaky Capacitors (Open, Corroded Traces)
Series: FR-A540; 400V
Capacity: 7.5kW; 10 HP
Version: Japanese

Mitsubishi FR-A520-1.5K-NA image FR-A520-1.5K-NA is an
Inverter-General Purpose manufactured by Mitsubishi
Discovered issues: Leaky Capacitors (Open, Corroded Traces), Bad Capacitor(s), Bad Cooling Fans, Excessive Dirt/Debris, No Display
Series: FR-A520; 200V
Capacity: 1.5kW; 2HP
Version: U.S. specification

Mitsubishi FR-A540-7.5K-CH image FR-A540-7.5K-CH is an
Inverter-General Purpose manufactured by Mitsubishi
Discovered issues: Bad Cooling Fans
Series: FR-A540; 400V
Capacity: 7.5kW; 10 HP
Version: Chinese specification

Mitsubishi FR-A520-22K-NA image FR-A520-22K-NA is an
Inverter-General Purpose manufactured by Mitsubishi
Discovered issues: Bad Output Transistors/SCRs
Series: FR-A520; 200V
Capacity: 22kW; 30 HP
Version: U.S. specification