Examples of troubleshooting methods for the contro

2022-07-27
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Examples of troubleshooting methods for frequency converter control and controller devices

(I) overvoltage fault

1 Fault phenomenon

the frequency converter stops running, and the display shows over voltage fault

2. Fault inspection process

see figure for fault inspection process

figure

3 Precautions for fault inspection

(1) there are two voltage detection voltage dividers and voltage feedback resistors at the upper end of the transformer and the middle of the inverter outlet bin, which are connected in parallel on the three-phase conductors

(2) the overvoltage trip threshold is generally set correctly during commissioning and should not be adjusted at will

(3) it is better for the frequency converter to adjust the speed by 2% ~ 3% each time. Especially when the speed is reduced, it is more necessary to control the rhythm of the adjustment speed

(II) overload fault

1 Fault phenomenon

the frequency converter stops running as soon as it is started, the frequency converter trips during operation, and the display screen displays over load fault

2. Fault inspection process

see figure for fault inspection process

figure

3 Precautions for fault inspection

(1) overload and overcurrent have little difference in protection requirements, and the cause of electrical equipment cannot be eliminated during inspection

(2) there is a difference between the setting of starting overload threshold and the setting of overload threshold. The calculation should be correct during adjustment and should not be confused

(3) the faults caused by motor, water pump and garbage shall be solved by professional units, and self operation shall be cautious

(III) driver output overcurrent fault

1 Fault phenomenon

the frequency converter stops running, and the display shows the drive output overcurrent (drive IOC)

2. Fault inspection process

see figure for fault inspection process

figure

3 Precautions for fault inspection

(1) the driver output current is different from the incoming line current, so pay attention to the difference

(2) take anti-static measures when checking and replacing the power interface board

(IV) ground fault

1 Fault phenomenon

the frequency converter stops running, and the display screen shows ground fault (ground fault needs to be designed for new fixture)

2. Fault inspection process

see figure for fault inspection process

figure

3 Precautions for fault inspection

(1) when testing the ground insulation with a megger, disconnect the output end of the frequency converter to prevent damage to the frequency converter

(2) during the test, the insulated support cable and motor can be tested at the same time, and the sectional inspection can be carried out in case of any problem

(3) the motor shall be repaired by a professional maintenance unit

(V) 15Vdc power failure

1 otherwise, the actual bending effect and temperature precision will be endangered due to poor circulating system Fault phenomenon

the self-test fails when the frequency converter is started, the frequency converter trips during operation, and the display shows 15Vdc supply fault (± 15Vdc supply fault)

2. Fault inspection process

see figure for fault inspection process

figure

3 Precautions for fault inspection

(1) the appearance is normal, which mainly means that the battery has no liquid leakage or corrosion

(2) the normal voltage at the test point is +5v, +15v, -15v

(3) pay special attention not to measure the wrong position during detection

(4) anti static measures shall be taken when replacing the battery or microcomputer board

(VI) 24VDC power failure

1 Fault phenomenon

the working power supply of interlocking device loses voltage, the working power supply of PLC loses voltage, the operating frequency converter trips, and the display shows 24VDC supply fault

2. Fault inspection process

see figure for fault inspection process

figure

3 Fault inspection precautions

(1) this fault is caused by the logic low-level signal feedback of pin 8 of IC3 on the PIB board

(2) during inspection, live operation shall be carried out. Not only the safety work shall be done strictly, but also the end legs of the measurement shall be familiar and cautious

(3) when measuring the working circuit path, the range of the multimeter should not be too large or too small, and anti-static work should be done to prevent damage to other components. Chongqing Gree air conditioner

(VII) medium voltage power failure

1 Fault phenomenon

the frequency converter trips suddenly during operation. When starting, the frequency converter cannot pass the self-test, and the display shows medium voltage supply fault

2. Fault inspection process

see figure

figure

3 for fault inspection process Precautions for fault inspection

(1) PIB is the power interface board; Fohb is the optical fiber interface board; Pl8 and ic19 are interface terminals

(2) check the interface connection for looseness, corrosion and dust

(3) when plugging the interface, do not use excessive force, but use slow force

(VIII) connector interruption fault

1 Fault phenomenon

during operation, the frequency converter suddenly trips and stops running, and the display shows the connector interruption fault (hub loss of enable)

2. Fault inspection process

see figure for fault inspection process

figure

non latching signal fault inspection steps:

(1) disconnect the motor wiring

(2) unplug the corresponding main control board from the interface board socket

(3) remove one group of units from the system device, that is, subtract 1 from the "installation number" in the 21\

(4) turn on the 380V power supply. If the fault does not disappear, replace the unplugged main control board. If the fault disappears, judge that the fault is one of the three units corresponding to the unplugged main control board

(5) replace the disconnected optical fiber interface on the main control board with the normal optical fiber interface, and check one by one to find out the fault unit

3. Precautions for fault inspection

(1) when the disconnected optical fiber interface is exchanged for inspection, it must be exchanged in the same phase, such as A1 and a2 A3, etc. must not be exchanged with A1, B3, C3, etc

(2) generally, you can check whether there is power unit fault record in 21\n menu first, which can shorten the inspection time to determine the fault point

(3) if the fault point cannot be found, you can re plug each optical fiber interface with the main control board, the main control board and the interface board once, which may eliminate the fault

(4) correct the changed value

(IX) self inspection failure of frequency converter without cause

1 If the speed is too fast, all elastic sections will be flushed quickly. Fault phenomenon

start the frequency converter, and it cannot enter the normal working state. The self inspection fails, and the display shows no fault

2. Fault inspection process

see figure for fault inspection process

figure

3 Precautions for fault inspection

(1) such faults are difficult to determine, and the fault scope can only be reduced by replacing the circuit board

(2) when replacing the microcomputer board, pay attention to the replacement of EPROM chip, or re input the working program of the frequency converter and reset the parameter value

(3) the control mode change-over switch is not only available on the frequency converter, 6kV power control cabinet, the upper PLC control cabinet and the local PLC cabinet

(x) poor contact fault of sampling feedback resistor

1 Fault phenomenon

the output of frequency converter is unstable, and the motor speed rises and falls uncontrollably

2. Fault inspection process

see figure for fault inspection process

figure

3 Precautions for fault inspection

(1) this fault is difficult to find when the speed change is small. Pay special attention to the speed change during operation. If this fault is found, stop the operation immediately and check carefully

(2) since the sampling resistor of the input power supply is on the top of the transformer compartment, it is easy to be neglected, which should be noted. Most of the faults are caused by poor contact of the input sampling resistor

(3) when checking the current transformer, open circuit is strictly prohibited

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