Mitsubishi Electric · Excitation & Generator Controls
Mitsubishi Electric FREQROL-A700 FR-A720-30K repair
Send the Mitsubishi Electric FREQROL-A700 FR-A720-30K for diagnosis and repair, or have an engineer come to the plant. Repair keeps the original excitation or generator control, its settings and its wiring in place.
Cost confirmed before any work starts · Warranty of 30 days to 6 months
At a glance
The Mitsubishi Electric FREQROL-A700 FR-A720-30K
- Manufacturer
- Mitsubishi Electric
- Model / part number
- FREQROL-A700 FR-A720-30K
- Also searched as
- FREQROLA700FRA72030K · FREQROL A700 FR A720 30K
- Description
- Frequency inverter
- Category
- Excitation & Generator Controls
- Service
- Diagnosis and component-level repair, onsite or ship-in
- Warranty
- 30 days to 6 months, confirmed before work starts
Mitsubishi Electric makes MELSEC PLCs, GOT operator panels, FR-series inverters, MELSERVO servo systems and CNC controls.
Common faults
What usually fails on a unit like the FREQROL-A700 FR-A720-30K
Excitation systems and generator controls regulate voltage and protect the generator, so faults show up as unstable voltage, field failures or tripping on load. AVR boards, thyristor bridges, controllers and engine control units can be repaired and tested.
Voltage hunting or instability
AVR control faults, sensing problems or worn feedback components.
Field failure and loss of excitation
Failed field thyristors or diodes, firing circuits or a fault in the exciter.
Overvoltage or undervoltage trips
Sensing circuit faults or wrong settings after a board change.
Controller and display faults
Dead controllers, lost settings and failed communication with switchgear.
Engine control unit faults
Speed control, sensor input and actuator driver faults on gensets.
Power semiconductors
Power semiconductors usually fail because of something else: a short in the load, a cooling fault or a supply surge. The repair replaces the failed devices and checks the drive circuits that switch them.
First checks
What to check before calling an engineer
Isolate and lock out the supply, and wait for stored energy to discharge, before opening anything.
Safe for plant staff
- Record alarms and event logs from the controller.
- Note the load and conditions when the fault appeared.
- Keep a copy of the controller settings.
Leave to a specialist
- Work on the field circuit or exciter.
- AVR tuning and setting after repair.
- Any test on a running generator.
Getting it fixed
How to get the FREQROL-A700 FR-A720-30K repaired
What to send with it
- The AVR, exciter board or controller.
- The generator rating and the alarm or log.
- Its settings, if they can be read out.
Onsite or ship-in
Technicians work onsite from our Hyderabad base and travel to plants across India; anything that can be removed can also be sent to MachineryFix from anywhere in the country.
Warranty. Repairs carry a warranty of 30 days to 6 months, depending on the item and the repair; the exact term is confirmed before work starts.
FAQ
FREQROL-A700 FR-A720-30K repair questions
Does the Mitsubishi Electric FREQROL-A700 FR-A720-30K need setting up after repair?+
Usually its settings are kept, but voltage regulation and any limits should be checked on the generator when it is refitted.
Does the Mitsubishi Electric FREQROL-A700 FR-A720-30K have to be sent in, or can an engineer come to the plant?+
Either. An engineer can diagnose it in place and repair it there or take it away, or the unit can be sent to MachineryFix from anywhere in India. The diagnosis and repair cost are confirmed before any work starts.
Is MachineryFix connected to Mitsubishi Electric?+
No. Mitsubishi Electric and the model name are used only to identify the equipment. MachineryFix is an independent repair service and is not affiliated with or endorsed by Mitsubishi Electric.
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Mitsubishi Electric and FREQROL-A700 FR-A720-30K are named only to identify the equipment. MachineryFix is not affiliated with or endorsed by Mitsubishi Electric.
FREQROL-A700 FR-A720-30K down?
Send the fault and what the machine was doing. We'll match an engineer who works on it.