Fuji inverter repair

Basic methods and steps for debugging the frequency converter:
1. No-load power-on test of the frequency converter
Connect the grounding terminal of the frequency converter to the ground.
Connect the power input terminal of the frequency converter to the power supply through the leakage protection switch.
3 Check whether the factory display on the display window of the inverter is normal. If it is incorrect, it should be reset, otherwise it will be required to be returned.
Be familiar with the operating keys of the inverter. General inverters have keys such as run, stop, programming (R), data confirmation (), increase (, ▲), decrease (,), etc. The definitions of the operation keys of different inverters are basically the same. In addition, some inverters have function keys such as monitoring (), reset (R), jog, and shift.
2. The inverter runs with motor under no load
.
.When setting the power and number of poles of the motor, the operating current of the inverter must be comprehensively considered.
.Set the maximum output frequency, base frequency and torque characteristics of the inverter. General frequency converters are equipped with multiple curves for users to choose. Users should choose the appropriate curve according to the nature of the load when using it. If it is a fan or pump load, the torque operation code of the frequency converter must be set to variable torque and reduced torque operation characteristics. In order to improve the low-speed performance of the inverter when starting, so that the torque output by the motor can meet the requirements for starting production loads, the starting torque must be adjusted. In the asynchronous motor frequency conversion speed regulation system, the control of torque is more complicated. In the low frequency band, since the influence of resistance and leakage reactance cannot be ignored, if it remains constant, the magnetic flux will decrease, thereby reducing the output torque of the motor. For this reason, the voltage must be appropriately compensated in the low frequency band to increase the torque. Generally, frequency converters are manually set and compensated by users.
3. Set the inverter to its own keyboard operation mode, press the run key and stop key, and observe whether the motor can start and stop normally.
. Be familiar with the protection code when the inverter fails during operation, observe the factory value of the thermal protection relay, observe the setting value of the overload protection, and modify it if necessary. The user of the frequency converter can set the electronic thermal relay function of the frequency converter according to the instruction manual of the frequency converter. When the output current of the frequency converter exceeds its allowable current, the over-current protection of the frequency converter will cut off the output of the frequency converter. Therefore, the maximum threshold value of the electronic thermal relay of the frequency converter does not exceed the maximum allowable output current of the frequency converter.
3. Trial operation with load
Manually operate the run stop button on the inverter panel, observe the motor running stop process and the display window of the inverter to see if there are any abnormalities.
.If the inverter has an overcurrent protection action during the process of starting and stopping the motor, the acceleration and deceleration time should be reset. The acceleration of the motor during acceleration and deceleration depends on the acceleration torque, while the frequency change rate of the inverter during starting and braking is set by the user. If the motor inertia or the motor load changes, when accelerating or decelerating according to the preset frequency change rate, the acceleration torque may be insufficient, causing the motor to stall, that is, the motor speed is not coordinated with the inverter output frequency, resulting in excessive speed. current or overvoltage. Therefore, it is necessary to set the acceleration and deceleration time reasonably according to the motor's moment of inertia and load, so that the frequency change rate of the inverter can be coordinated with the motor speed change rate.
The way to check whether this setting is reasonable is to first select the acceleration and deceleration time based on experience. If overcurrent occurs during the starting process, the acceleration time can be appropriately extended. If overcurrent occurs during the braking process, flow, extend the deceleration time appropriately. On the other hand, the acceleration and deceleration time should not be set too long, as too long time will affect production efficiency, especially when starting and braking are frequent.
3. If the frequency converter is still protected within a limited time, the start and stop operating curve should be changed from a straight line to a shape, shape line or shape, inverse shape line. When the motor load inertia is large, longer start and stop times should be used, and the operating curve type should be set according to its load characteristics.
.If the inverter still has operating faults, try to increase the maximum current protection value, but cannot cancel the protection. There should be a protection margin of at least ~.
. If the inverter operation failure still occurs, the inverter should be replaced with a larger power level
. If the motor driven by the inverter cannot reach the preset speed during the starting process, there may be two situations:
If electromechanical resonance occurs in the system, it can be judged from the sound of the motor running.
The resonance point can be avoided by setting the frequency jump value. Generally, the frequency converter can set the three-level jump point. When the controlled inverter drives an asynchronous motor, in certain frequency ranges, the motor's current and speed will oscillate. In severe cases, the system cannot operate. Even over-current protection occurs during acceleration and the motor cannot start normally. When the motor is under light load or It is more serious when the moment of inertia is small. Ordinary frequency converters are equipped with a frequency jump function. The user can set the jump point and jump width on the curve according to the frequency point where the system oscillates. When the motor accelerates, it can automatically skip these frequency bands to ensure that the system can operate normally.
The torque output capability of the motor is not enough. Different brands of inverters have different factory parameter settings. Under the same conditions, the load capacity of the motor is different. The load capacity of the motor may also be different due to different control methods of the inverter. Due to different output efficiencies of the system, the loading capacity will vary. For this situation, the value of torque boost can be increased. If it cannot be reached, you can use the manual torque boost function. Do not set it too high. The temperature rise of the motor will increase at this time. If it still doesn't work, a new control method should be used. For example, Hitachi inverter uses a constant ratio method. When the startup cannot meet the requirements, the speed sensorless space vector control method is used, which has greater torque output capability. For fan and pump loads, the torque reduction curve value should be reduced.
4. Connect the inverter to the host computer for system debugging. After the manual basic settings are completed, if there is a host computer in the system, connect the control line of the inverter directly to the control line of the host computer, and connect the control line of the inverter to the host computer. The operating mode is changed to terminal control. According to the needs of the host computer system, set the range of the inverter's receiving frequency signal terminal, and the response speed of the inverter to the analog frequency signal sampling. If another monitoring meter is needed, the monitoring value of the analog output should be selected, and the range of the inverter output monitoring value terminal should be adjusted.