Sunwoele VFD (Variable-frequency Drive) common faults and solutions

(1) Fault P.OFF

????The Sunwoele VFD (Variable-frequency Drive) power-on display P.OFF will display 0 after a delay of 1~2s, indicating that the VFD (Variable-frequency Drive) is in the standby state. In the application, if the VFD (Variable-frequency Drive) keeps displaying P.OFF without jumping to 0 after power-on, the main reasons are that the input voltage is too low, the input power supply is out of phase, and the VFD (Variable-frequency Drive) voltage detection circuit is faulty. , When processing, first measure the three-phase input voltage of the power supply. The normal voltage of the R, S, and T terminals is three-phase 380V. If the input voltage is lower than 320V or the input power supply is out of phase, the external power supply failure should be ruled out. If the input power is normal, it can be judged that the VFD (Variable-frequency Drive) internal voltage detection circuit or phase loss protection is faulty. For Sunwoele G1/P1 series 90kW and above VFD (Variable-frequency Drive) models, the main cause of the fault is internal phase loss The detection circuit is abnormal. The phase loss detection circuit is composed of two single-phase 380V/18.5V transformers and a rectifier circuit. Most of the faults are caused by detection of transformer faults. During processing, it is possible to measure whether the output voltage of the transformer is normal.

(2) Fault ER08

????The ER08 fault code of Sunwoele VFD (Variable-frequency Drive) indicates that the VFD (Variable-frequency Drive) is in an undervoltage fault state. The main reasons are that the input power is too low or lack of phase, the internal voltage detection circuit of VFD (Variable-frequency Drive) is abnormal, and the main circuit of VFD (Variable-frequency Drive) is abnormal. The general VFD (Variable-frequency Drive) voltage input range is 320V~460V. In practical applications, when the VFD (Variable-frequency Drive) is fully loaded, under-voltage protection may occur when the input voltage is lower than 340V. At this time, the power grid should be increased. The input voltage or VFD (Variable-frequency Drive) should be used with derating; if the input voltage is normal and the VFD (Variable-frequency Drive) has an ER08 fault during operation, it can be judged as an internal fault of the VFD (Variable-frequency Drive), which may be the main The KS contactor in the circuit jumps off, so that the current-limiting resistor is connected in series to the main circuit when the VFD (Variable-frequency Drive) is running. At this time, if the VFD (Variable-frequency Drive) is running with load, ER08 fault will occur. At this time, it can be Exclude whether the contactor is damaged or the contactor control circuit is abnormal; if the main circuit of the VFD (Variable-frequency Drive) is normal, the cause of the ER08 alarm is mostly the fault of the voltage detection circuit. Generally, the voltage detection circuit of the VFD (Variable-frequency Drive) is A set of output of the switching power supply is sent to the CPU processor after sampling and comparison circuits. When the set value is exceeded, the CPU outputs a fault blocking signal according to the comparison signal, blocks the IGBT, and displays the fault code at the same time.

(3) Fault ER02/ER05

????The fault code ER02/ER05 indicates that the VFD (Variable-frequency Drive) has an overcurrent or overvoltage fault during deceleration. The main reason is that the deceleration time is too short and the load feedback energy is too large to be released in time. If the motor drives a load with large inertia, when the VFD (Variable-frequency Drive) frequency (that is, the synchronous speed of the motor) drops, the actual speed of the motor may be greater than the synchronous speed. At this time, the motor is in the state of generating power, and this part of the energy will pass through the VFD (Variable-frequency Drive) inverter circuit returns to the DC circuit, so that the VFD (Variable-frequency Drive) has overvoltage or overcurrent protection. During on-site processing, the deceleration time of VFD (Variable-frequency Drive) can be extended without affecting the production process. If the load inertia is large and it is required to stop within a certain period of time, an external brake resistor and brake must be installed. Unit, Sunwoele HSF600 series VFD (Variable-frequency Drive) models below 22kW have a built-in braking unit, only need to add an external braking resistor, and the resistance can be selected according to the standard in the product description. Type requires additional braking unit and braking resistor.

????ER02/ER05 faults generally only appear during the VFD (Variable-frequency Drive) deceleration and shutdown process. If the VFD (Variable-frequency Drive) has this fault in other operating states, it may be inside the VFD (Variable-frequency Drive) It is caused by the abnormality of the switching power supply part, such as the voltage detection circuit or current detection circuit.

(4) Fault ER17

????Code ER17 means current detection failure. General VFD (Variable-frequency Drive) current detection generally uses a current sensor to detect and display the VFD (Variable-frequency Drive) operating current by detecting the two-phase output current of VFD (Variable-frequency Drive) And the protection function, the output current outputs a linear voltage signal through the current sensor, which is sent to the CPU processor through the amplification and comparison circuit. The CPU processor judges whether the VFD (Variable-frequency Drive) is in an over-current state according to different signals. If the output current exceeds the protection value , then the fault blocking protection circuit will act and block the IGBT pulse signal to realize the protection function.

????The main reason for the ER17 failure of Sunwoele VFD (Variable-frequency Drive) is the failure of the current sensor or the abnormality of the current detection amplification comparison circuit. The former can be solved by replacing the sensor, and the latter is mostly related to the current detection IC circuit or IC chip. Replace the related IC or repair the related power supply.

(5) Fault ER15

????The code ER15 indicates that the IPM and IGBT of the inverter module are faulty. The main reason is that the output is short-circuited to ground, the cable from the VFD (Variable-frequency Drive) to the motor is too long (more than 50m), and the inverter module or its protection circuit is faulty. When handling on-site, remove the motor wire first, measure the VFD (Variable-frequency Drive) inverter module, observe whether there is a short circuit in the output, and check whether the motor is short-circuited to the ground and whether the motor wire exceeds the allowable range. If the above is normal, it may be VFD (Variable-frequency Drive) internal IGBT module drive or protection circuit is abnormal. Generally, the IGBT overcurrent protection operates by detecting the tube voltage drop when the IGBT is turned on, as shown in Figure 3.

????When the IGBT is normally turned on, its saturation voltage drop is very low. When the IGBT is over-current, the tube voltage drop VCE will increase with the increase of the short-circuit current. When it increases to a certain value, the detection diode DB

????The reverse conduction, at this time the reverse current signal is sent to the CPU processor through the IGBT drive protection circuit, and the CPU blocks the IGBT output to achieve protection. If the detection diode DB is damaged, the Sunwoele VFD (Variable-frequency Drive) will have an ER15 fault, and the detection diode can be replaced during on-site processing to eliminate the fault.

(6) Fault ER11

????The ER11 failure of Sunwoele VFD (Variable-frequency Drive) means that the VFD (Variable-frequency Drive) is overheated. The possible reasons are: air duct blockage, high ambient temperature, damaged cooling fan and abnormal temperature detection circuit. When handling on-site, first judge whether the temperature of the VFD (Variable-frequency Drive) is too high. If the temperature is too high, you can first troubleshoot according to the above reasons; if the temperature of the VFD (Variable-frequency Drive) is normal. The reason is that the temperature detection circuit is faulty. The seven-unit inverter module used by Sunwoele models below 22kW has a temperature element integrated inside. If this part of the circuit in the module fails, an ER11 alarm will also occur. On the other hand, the same failure will occur when the temperature detection and calculation circuit is abnormal.

Conclusion

????With the continuous expansion of the application scope of VFD (Variable-frequency Drive), users are becoming more and more familiar with VFD (Variable-frequency Drive), and the problems in the use of VFD (Variable-frequency Drive) are roughly similar. (Variable-frequency Drive) The possible faults and general treatment methods in use, I hope it will be helpful to users, and at the same time, it can be used as a reference for people in the industry.