Danfoss frequency converter is a commonly used brand on the market, but if it is used for a long time, there will always be some faults, then it is more typical than just a few faults. Today we will take a look at it together, what is its solution? Let's take a look.
Frequency converter compositionThe frequency converter is composed of two main parts: the main circuit and the control circuit. The main circuit is composed of three main parts: rectifier (rectifier module), intermediate circuit (filter circuit) and inverter (high-power crystal module). The control circuit is composed of three main parts. The circuit board is composed of a single chip microcomputer, a driving circuit and an optical isolation.
Common faults in the inverter are: multiple faults occur (alarms 5, 6, 7, 8) ground fault (alarm 14), motor UVW phase loss (alarm 31.32.33), communication faults, etc.
Switching power supply is damaged
This is a common fault of many inverters, usually caused by damage to the components of the switching power supply or short-circuit of the load. Danfoss inverter uses the new pulse width integrated controller UC2844 to adjust the output of the switching power supply, while the UC2844 also has Current detection, voltage feedback and other functions. When no display occurs, there is no voltage at the control terminal, and the 24V fan does not run, we should first consider whether the switching power supply is damaged (generally UC2844 or resistance damage). If you can't judge whether the power supply is faulty, you can test it with an external 24V power supply. If the test result is normal, you can determine that it is a power failure.
The letter "14" is displayed on the screen.
The “ALARM14†alarm appears on the LCD screen of the inverter. The inverter can't work. Press the RESET button to reset after re-powering. Then restart the alarm again. Check the operation manual for grounding alarm. Check that the motor and related cables have no ground fault. This means that the fault is in the inverter. The reason why the analysis circuit causes the grounding alarm is that the Hall sensor output voltage signal is sent to the current sampling board and then sent to the operational amplifier for comparison. The result is too large, the detection part of the Hall sensor is normal, and the detection of the ceramic-based film integrated resistor R501 is detected. The resistance value has become infinite due to corrosion, which causes the grounding to be poor, causing the signal to be too strong, causing an alarm, and no original replacement. The high-power chip resistor with the same resistance value is soldered on the above, and the operation is normal after restarting. Ground fault is a fault that is often encountered in normal times. In addition to the cause of the problem of grounding of the motor, the most likely part of the fault is the Hall sensor and the signal transmission resistor, because they are affected by environmental factors such as temperature, humidity, and corrosive gases. Large, the working point is prone to drift, resulting in grounding alarm.
“ALARM 13†alarm is displayed on the screen
The “ALARM13†alarm is displayed on the screen, and can be manually reset. It is normal when the speed is not increased. When the speed is increased, it will alarm and re-power. No sound is heard from the internal relay. It is suspected that the contactor KMI short-circuited in parallel with the charging resistor R401 causes If the current is too large, use a multimeter to measure the voltage at both ends of the KMI coil. The DC resistance of the power-off coil is infinite. After the new coil is replaced, the power is tested and everything is normal.
Overcurrent reasons:
(l) When restarting, it will trip at a speed. This is a very serious overcurrent phenomenon. The main reasons are: open contactor, overload, mechanical failure; inverter module damage; motor torque is too small.
(2) Immediately after the power is turned on, this phenomenon is generally not reset. The main reasons are: module damage, drive circuit damage, current detection circuit damage. Paper reference network.
"ALARM 8" low pressure alarm
The “ALARM8†alarm on the LCD screen of the inverter cannot be reset. After checking the line terminal 104(l) is the voltage detection point, the short circuit of the contactor KMI of the signal diagram 3 causes the current to be too large, and is sent to the control board via IC403 and internally. Compared with the parameter setting voltage, if it is lower than the lower limit of the parameter, the inverter will stop and alarm display the fault. There is no voltage at 104 (11), the normal is 2.3 V, the fault point is in front, and the IC403 (3) is not measured. Voltage, D1 negative electrode has no DC voltage, the transformer has AC output,
It is judged that the 4R7 resistor is damaged, and the resistor is energized after the resistor is changed, and the trial operation is normal.
"ALARM29" heat sink temperature is too high alarm
The “ALARM29†alarm on the LCD screen of the inverter cannot be reset. This is a fault we often encounter. When such a fault occurs, we should first look at whether the temperature display of the panel exceeds the upper limit of the parameter setting. If it exceeds the actual temperature, if it does not match, the detection circuit is faulty. If the temperature is not consistent with the reality, the circuit is measured. 14V is normal, there is no voltage at both ends of the plug, check the resistance of R207, R208 is infinite, and everything is normal after replacing the new one.
The inverter can start with frequency and no voltage
The inverter display is normal, and can start and there is frequency change but no AC voltage is generated. The fault of the test panel is still the same, indicating that the fault is in the power part, and the IGBT and related circuits are tested normally. When the cable of MK1-MK2 is found, it is found. The contact resistance of the cable on the cable is too large due to corrosion. After repairing with alcohol and sharp needles, the power is re-energized and everything is normal.
The inverter screen has no display, the light strobes
The inverter has no display but the lamp strobes, there is no change in the control panel. It is suspected that there is a fault in the power supply. The output of the power supply on the power supply board has obvious flashing, indicating that the power supply has a short-circuit fault, and the power is disconnected by hand. When the device touches the IC408, it finds that its temperature is too high. It uses a multimeter to measure the internal severe short circuit. After the replacement, the voltage is normal after the power is turned on. The motor is tested and no fault is found.
When the inverter panel is displayed, it is good or bad.
When the inverter panel is displayed, it is good or bad. The control panel is still faulty. It is suspected that the power supply is in poor contact. Check that all the power supplies are normal. Check the power line between the power board and the control board. It is found that the wired contact is bad. everything is normal. Paper reference network.
Rectifier bridge damage
When the inverter is running, the pre-level insurance is burnt, the air is tripped, and there is abnormal noise inside the inverter. During the inspection, the rectifier bridge is damaged, several obvious cracks are blown up, and the whole bridge has been short-circuited. The model number is SKB30/12. The current is 30A and the pressure is 1200V. It fully meets the technical requirements. Because the load of the inverter is the drag roller and the cutter head, the parking inertia is large, and there is regenerative overvoltage when parking. The DC circuit voltage is caused by the regenerative power. The rise, sometimes exceeding the allowable value, the intermediate voltage ten regenerative voltage exceeds the rectifier bridge withstand voltage value, which is the cause of the rectifier bridge burst. According to the above reasons, we adjust the individual parameters of the inverter, such as the deceleration time is extended from the original 5s to 10s, and the three-phase output U, V, W pressure sensitive resistors (the connection is â–³ connection, the withstand voltage of the varistor is 1000V). Through the above improvement, the failure rate of the inverter is significantly reduced.
Three-phase rectifier bridge module detection method: the digital multimeter is dialed to the diode test file, and the red and black test leads are used to measure the characteristics of the forward and reverse diodes between the R, S, T phase and the P and N poles to check and judge the rectifier bridge. Is it intact? The larger the difference between the measured forward and reverse characteristics is, the better; if the positive and negative directions are zero, it means that the detected one phase has been broken through; if the positive and negative directions are infinite, it means that the detected phase has been broken. The rectifier bridge module must be replaced as long as one phase is damaged.
Routine maintenanceThe operator must be familiar with the basic working principle and functional characteristics of the inverter and have basic knowledge of electrician operation. Before routine maintenance of the inverter, it must be ensured that the total power supply of the equipment is completely cut off; and after the inverter lamp is completely extinguished for 5-30 minutes (according to the power of the inverter). Paper reference network. Should pay attention to check the grid voltage, improve the surrounding environment of the inverter, motor and circuit, regularly remove the dust inside the inverter, and minimize the failure rate of the inverter by strengthening equipment management.
cooling fan
The power module of the frequency converter is the most heat-generating device, and the heat generated by its continuous operation must be discharged in time. The life of the general fan is about 20kH-40kH. According to the continuous operation of the inverter, it is necessary to replace the fan once in 3-5 years to avoid malfunction caused by poor heat dissipation.
Filter capacitor
Intermediate circuit filter capacitor: also known as electrolytic capacitor, its main function is to smooth the DC voltage, absorb the low frequency harmonics in DC, the heat generated by its continuous operation plus the heat generated by the inverter itself will accelerate the drying of the electrolyte, directly affecting The size of its capacity.
Under normal circumstances, the capacitor has a service life of 5 years. It is recommended to check the capacitance capacity once a year regularly. Generally, the capacity should be replaced by more than 20%. At the same time of maintenance, the inverter should be carefully checked, and the power should be sent periodically. The motor should work at a low frequency of 2 Hz for about 10 minutes to ensure that the inverter works normally.
ConclusionThe high-tech content of the inverter is a combination of strong and weak current, but it can cause damage to the inverter if it is used improperly or accidentally. In order to make the normal operation of the inverter less faulty, the technical level of the maintenance personnel is extremely high, and it is also necessary for the maintenance technician to fully understand the on-site environment, equipment, and process.
ZGAR Vape Pods 1.0
ZGAR electronic cigarette uses high-tech R&D, food grade disposable pods and high-quality raw material. A new design of gradient our disposable vape is impressive.We equip with breathing lights in the vape pen and pods.
Our team has very high requirements for product quality, taste allocation and packaging design. Designers only use Hong Kong designers, e-cigarette liquid only imports from the United States, materials are food grade, and assembly factory wants medical grade without ground workshop.
We offer best price, high quality Pod System Vape,Pods Systems Touch Screen,Empty Pod System, Pod Vape System,Disposable Pod device,Vape Pods to all over the world.
Pods,Vape Pods,Pod Systems,Atomizer, E-cigarette, Empty Pod Vape Manufacturer and Supplier in China
ZGAR INTERNATIONAL TRADING CO., LTD. , https://www.zgarpods.com