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The novice can solve the frequency converter common fault diagnosis and processing.(9)
- Jun 01, 2018 -

1.10 common faults and treatment methods of Cornwall inverter

1.10.1 fault P.O FF

The Po FF is displayed on the convo converter and 0 is displayed after 1 yao 2 s delay, indicating that the converter is in standby mode.In the application, if the frequency converter shows P.OFF without jumping 0 after power on, the main reasons are the low input voltage, the missing phase of the input power supply and the circuit fault of voltage detection of the frequency converter.Should be measured when processing power three-phase input voltages, R, S, T terminal voltage of 380 V three-phase normally, if the input voltage is lower than 320 V or input power lack, should exclude external power failure.If the input power is normal, it can be judged to be the internal voltage detection circuit of the frequency converter or the fault of missing phase protection.For the 90 kW and above frequency converters of the kW G1/P1 series, the fault is mainly caused by the abnormal circuit of internal phase missing detection.The fault detection circuit consists of two single-phase 380v / 18.5v transformers and rectifier circuits. The fault causes are mostly transformer fault detection.

1.10.2 fault ER08

The ER08 fault code of the convo converter indicates that the converter is under voltage fault.The main reasons include low input power supply or missing phase, abnormal voltage detection circuit inside frequency converter, abnormal main circuit of frequency converter.The voltage input range of universal inverter is 320~460 V.

In practical applications, when the inverter is running at full load, undervoltage protection may occur when the input voltage is lower than 340 V. At this point, the input voltage of the power grid or the inverter should be increased.If the input voltage is normal and ER08 fault occurs in the frequency converter during operation, it can be judged as the internal fault of the converter.If the main circuit of the frequency converter is normal, the main reason for ER08 alarm is the failure of the voltage detection circuit.General inverter voltage detection circuit for a group of output switching power supply, after sampling, comparison circuit to the CPU processor, when more than the set value, the CPU according to the comparison of signal output fault block signal, blockade IGBT, at the same time shows fault code.

ER02 / ER05 1.10.3 malfunction

The fault code ER02/ER05 indicates that the frequency converter has an over-current or over-voltage fault during deceleration, mainly because the deceleration time is too short and the load feedback energy is too large to be released in time.If a motor to drive the large inertia load, when the inverter frequency (i.e., the synchronous speed of the motor) falls, the actual speed may be greater than the synchronous speed of the motor, when the motor is in power position, this part of the energy will be through the inverter circuit to return to the dc circuit of frequency converter, so that the inverter over-voltage or over-current protection.On-site processing in the case of does not affect the production process can be prolonged deceleration of the inverter, if the load inertia is larger, and requirements in a certain period of time when stop, should add external braking resistor and brake unit, Cornwall G2 / P2 series models built under 22 kW inverter braking unit, simply add external braking resistor, resistance matching could be selected according to the product description standard;For models with power over 22 kW, additional brake units and brake resistors are required.

ER02 / ER05 fault in the inverter only commonly arise in the process of slowing down, if the inverter in the problem with one of the other running condition, may be inverter switching power supply part of the internal, such as voltage or current detection circuit detecting circuit is abnormal.

1.10.4 fault ER17

Code ER17 indicates current detection failure.Generally, current sensors are used in current detection of universal inverter. As shown in figure 5, detection, display and protection of operating current of inverter can be realized by detecting the two-phase output current of inverter.Output electricity flows through the current sensor (figure of H1, H2) linear voltage output signal, amplifying comparison circuit to the CPU processor, the CPU processor according to different signal to determine whether a frequency converter in the over current state, if the output current more than protection value, the fault block protection circuit action, blockade IGBT pulse signal, realize the protection function.

Convo ER17 failures, the main reason for the current sensor failure or abnormal current amplification comparison circuit, the former can be solve by changing the sensor, which is mostly related to abnormal current IC circuit, or IC chips working power supply, can be replaced by IC or maintenance of related power solution.

1.10.5 fault ER15

Code ER15 indicates the IPM and IGBT fault of the inverter module, mainly due to the output to ground short circuit, the cable length from the inverter to the motor (over 50 m), the inverter module or its protection circuit fault.The scene processing down motor wiring first, measuring frequency inverter module, observe whether there is a short circuit, the output at the same time check whether the motor is of short circuit and motor wiring whether to exceed the permitted range, such as the above all normal, could drive for internal IGBT inverter module or abnormal protection circuit.In general, IGBT overcurrent protection is through the detection of IGBT conduction through the action of pressure drop.