Ask for help for Mitsubishi FR A540 7 5K undervoltage protection issues

One. Please first increase the power supply voltage of the main circuit to about 380V, and increase the capacity of the power supply, so as to ensure the normal operation of the inverter. If the DC bus voltage is lower than 430V, there will be under-voltage protection, such as the 460V voltage you measured, it may be at the critical point of under-voltage protection, once the voltage fluctuates, it may be protected.

I have a Mitsubishi FR-F740-S75K-CH inverter in my hand, and the current fault phenomenon is that after the inverter runs for more than 10 minutes, the frequency is around the stable value of 30Hz (given with 4-20mA current, the frequency is about 30Hz, and the fluctuation is very small) begins to decline until it stops. At the same time, it shows that EOU1 and or EOU2 are faulty, and after checking the manual, they are all caused by the DC bus voltage is too high. The parameters are no problem, and the good inverter next to it is exactly the same.

There are no problems with the load and peripheral control signals. The module that started to change is not original, and EOU1 is displayed. After changing the original module, EOU2 is displayed, please help me diagnose it.

Thank you for the guidance of the two teachers upstairs, when the grid voltage is above 350V, the inverter works normally, but the power supply of the power grid at the customer is unstable, and sometimes the machine cannot work when it is below 330V, while other machines (using different brands of inverters) still work normally! It is true that the method of increasing the voltage is the root cause, but only a power regulator can be used. A three-phase 10kw voltage regulator is about 20,000 yuan, and it is really uneconomical to add 20,000 yuan to this machine alone.

I consulted the manuals of a variety of different brands of inverters, some of which did not indicate the specific values, and all of them were marked with DC bus voltage of 400V as the protection threshold. May I ask Mr. Li Chunfa how to understand what you said"Danger"This? Can you be specific?

Can it work above DC 400V without entering the protection?

Adjust the parameters so that the panel displays the DC bus voltage. The bus display is not normal, and the 7800 or related DC detection is bad. The bus bar shows normal, with load undervoltage, thyristor or related trigger circuit fault.

The voltage on the DC side is only 460V, and the low voltage is also dangerous.

Name: Undervoltage Protection.

Description: If the supply voltage of the drive drops, the control loop may not function properly. or cause insufficient torque of the motor.

Increased fever. For this purpose, when the supply voltage drops below 300V, the inverter output is stopped.

If there is no short-circuit between P and P1, the under-voltage protection function operates.

Check points: Whether there is a large-capacity motor start. Whether there is a short-circuit chip or a DC reactor between p, p1.

Processing: Whether there is a large capacity motor start. Whether there is a short-circuit chip or a DC reactor between p, p1.

I know what the reason is, it is that the optocoupler A7800 is broken, just replace it.

We've got you covered! We are a Mitsubishi Repair & Parts Center!

- Is the Mitsubishi air conditioner malfunctioning? With my 7 years of experience in repairing air conditioners, I will tell you how to solve these faults, which should save you a lot of detours.

First: When the air conditioner fails, you can go to the [air conditioner failure** network] to inquire, down to the brand and model of the air conditioner. Universal remote control** query can go to the universal remote control area for inquiry.

When encountering a failure of the air conditioner, we must strictly follow the scientific procedures, and do not act blindly and disassemble at will when the situation is unclear, the fault is unclear, and there are countless in the heart. The consequence of this often amplifies existing faults, increases operating costs, shortens the normal service life of equipment, and leads to early scrapping of equipment.

The air conditioner is not refrigerated or does not refrigerate.

This problem is most common, and the lack of fluorine in air conditioners is the key.

When the machine is turned on, first touch the trachea and judge it by the temperature.

If it is cold, the speed of the fan may be low.

The inner tube scales and dust are cleaned or replaced.

If the inner tube is not considered cool, the thick tube may be flattened.

The return air temperature is not cool, and then touch the intake air to judge.

The air intake is cold and frosty, and fluoride is added to try again.

If the frost slowly disperses, it is a good decision to lack fluoride.

It is not difficult to see the aging of the press, and the lack of exhaust is the key.

Four-way gas is also commonly judged by fluoride collection.

High-pressure scales must be seen to be dirty, and they will be slow to refrigerate.

The air conditioner will be cool for a while, and it will not be cool for a while, and most of them are high-pressure protection.

If you still don't understand, it is recommended that you go to the [Air Conditioning Fault **Net] basic knowledge area and take a look at the maintenance cases to get started.

I hope you get better and better, and the new year will be smooth, all your wishes will come true, you will be healthy, and your family will be happy.

- Finally, I wish the work to go well, fix the air conditioner as soon as possible, and live a happy ———

Ryoji air conditioner GJ outdoor unit failure**.

LED flashing Cause of failure The LED is on.

LED1 Phase Sequence Error The indoor output control signal is normal.

LED2 Phase Loss The indoor output control signal is normal.

LED3 Outer Ring Temperature Abnormality 63H1 Operation.

LED4 63H2 action compressor starts.

LED5 Outdoor 51C Action Protection Outdoor Fan Start LED6 Outdoor 26C Action Protection Four-way valve start.

LED7 Overheat Protection Pressure relief valve activation.

LED8 control input circuit is abnormal Crankcase heater start light position Cause of failure.

12--29 Outdoor fault (check the connection wire, refrigerant, and temperature sensor of the outdoor unit) 11--28 Abnormal outdoor ambient temperature or control board fault.

10--27 Abnormal inner tube temperature or control board failure.

7--24 Anti-cold air protection (indoor air inlet and outlet are barrier-free, indoor motor) Note: The indoor fault lamp is displayed on the left side of the panel, and when the indoor JP4 short circuit is plugged in, there is no delay function when the indoor JP4 is powered on for the first time, otherwise it is the opposite. The indoor JP2 short-circuit plug-in can change the temperature of the cold air from 1 degree to minus 2 degrees.

Mitsubishi Heavy Industries: Show content Cause of failure.

Check that the light (yellow) is shining and the room tube temperature or ambient temperature is abnormal.

The running light (yellow) flashes and the secondary power supply is protected from overvoltage and undervoltage.

Check that the light (yellow) flashes once for overcooling protection.

Check that the light (yellow) is shining twice for overheat protection.

Check that the light (yellow) flashes three times and the outdoor unit protection device operates.

Check the light (yellow) flashes four times The float switch acts, the pump drains abnormally Check the light (yellow) flashes five times The indoor pipe temperature sensor is checked above 25 degrees.

It is a computer board failure, but it can be replaced with a universal air conditioning control board (the best, less than 200 yuan), and the original computer board is generally too expensive.

The cable between the indoor unit and the outdoor unit is bitten by rats or the computer board is malfunctioning.

No need to check, the compressor is broken, and the same is true of my house, so it is good to replace the compressor.

If the main circuit is not connected, how can the motor operate, it may be that the capacitor in the inverter is not completely discharged.

There is an R1 S1 terminal and R S is connected, and the power converter is also powered on R1S1, but it lacks a phase, so it will report an undervoltage fault and shut down after working for a while, if you want to separate the power supply, remove the R1S1 terminal and remove the connecting piece, there will be no above problem.

No, the motor does not have any action

The operation logic of the door is abnormal.

Fault**: 0 Serial transmission error.

1 Inverter overcurrent.

2 +12V undervoltage.

3. The main circuit is undervoltaged.

4 CPU WDT error.

5 GS (Door Lock) Error.

6 Wrong position switch.

7 The door opening and closing command is incorrect.

9 Door closing operation error.

a Closing and closing the door for speeding.

a Error with the position counter.

b Error with position monitor.

c Encoder error.

d Overload.

d gs disconnect indication.

e Insufficient balance of the DLD.

f Overspeed check.

f GS is indicated when released.

The general working principle of the inverter is like this, which is controlled by a constant voltage frequency ratio in order to prevent a sharp change in current. v f is a fixed value. When the frequency is high, the voltage will naturally increase.

The voltage of the motor is very wide, so you can use it with confidence. However, it should be noted that the F series is unstable at ultra-low frequencies, such as setting 1Hz to these frequencies will not operate stably. The A series can be realized by vector control.

Ultra-low frequency is ultra-low speed, which is achieved by servo motors.

No, bold use is! Even if there is an undervoltage, the inverter has protection, although I don't like small Japanese things, but the quality of the performance is still OK, rest assured to use it,

No problem, you can use it! This is what the use of frequency conversion can satisfy! The excitation current of the motor will not cause damage to the motor!

It is under-voltage protection, to see if there is a large-capacity motor start, and whether there is a short circuit piece or DC reactor between P and P1.