First, the inverter no-load power test
1 Ground the inverter ground terminal.
2 Connect the inverter’s power input terminal to the power supply through the earth leakage protection switch.
3 Check the inverter display window factory display is normal, if not correct, should be reset, or request returned.
4 familiar with the operation keys of the inverter. The general inverter has 6 keys, such as RUN, STOP, PROG, DATAPENTER, UP, ▲, DOWN etc., different inverter operation The definitions of keys are basically the same, and some function keys such as MONITORPDISPLAY, RESET, JOG, SHIFT are also available.
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Second, the inverter with motor running without load
1. Set the motor power, the number of poles, to consider the inverter operating current.
2. Set the inverter’s maximum output frequency, base frequency, set torque characteristics. General frequency converter is equipped with multiple VPf curves for users to choose, the user should choose the appropriate VPf curve according to the nature of the load. For fan and pump loads, set the torque converter operating torque code to variable torque and torque down. In order to improve the low-speed performance when the inverter is started, the torque output by the motor can meet the requirement of starting the production load and adjust the starting torque. In the induction motor speed control system, the torque control is more complicated. In the low frequency band, the influence of resistance and leakage reactance can not be neglected. If VPf is kept constant, the flux will decrease and the output torque of the motor will be reduced. To this end, in the low-frequency voltage to be properly compensated to improve the torque. General inverter are manually set by the user to compensate.
3. Set the inverter to its own keyboard operation mode, press the run key, stop key to observe whether the motor can start and stop normally.
4. Familiar with the protection code of inverter running fault, observe the factory setting of thermal protection relay, observe the setting value of overload protection and can be modified if necessary. The inverter user can set the inverter’s electronic thermal relay function according to the instruction manual of the inverter. When the inverter output current exceeds its allowable current, the inverter over-current protection will cut off the inverter output. Therefore, the maximum limit of inverter thermal relay does not exceed the maximum allowable output current of the inverter.
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Third, with load test run
1. Manually operate the inverter running stop key to observe the process of stopping the motor and the inverter’s display window to see if there is an abnormal phenomenon.
2. If overcurrent protection occurs during stop of the motor when starting P, accelerate P 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 startup and braking is set by the user. If the motor inertia or motor load change, according to the pre-set rate of change when the speed increase or deceleration, there may be insufficient acceleration torque, resulting in stalling the motor, that is, the motor speed and inverter output frequency is not coordinated, resulting in Current or over voltage. Therefore, it is necessary to properly set the acceleration and deceleration time according to the motor’s moment of inertia and load, so that the frequency change rate of the inverter can be coordinated with the rate of change of the motor speed.
Check whether this setting is reasonable or not, according to the experience of the first choice of acceleration and deceleration time to set, if there is over-current during the start-up process, may be appropriate to extend the acceleration time; if the overcurrent during braking, Appropriate to extend the deceleration time. On the other hand, Canada, deceleration time should not be set too long, too long will affect the production efficiency, especially frequent Kai, braking.
3. If the frequency converter is still protected for a limited time, change the operating curve at which startup P stops, changing from straight to S, U, S, U-shaped. When motor load inertia is large, a longer start-stop time should be used and the type of operating curve set according to its load characteristics.
4. If there is still a running fault in the inverter, try increasing the protection value for the maximum current, but you can not cancel the protection. Leave a margin of at least 10% -20%.
5. If the inverter is still operating fault occurs, should be replaced by a higher level of power inverter
6. If the inverter drives the motor less than the preset speed during start-up, there may be two situations:
(1) Electromechanical resonance occurs in the system and the sound from the motor can be judged.
By setting the frequency hopping value, you can avoid the resonance point. General inverter can set three jump points. When the inverter controlled by VPf drives an asynchronous motor, the current and speed of the motor will oscillate in some frequency segments, and the system will not run in severe cases. Even if overcurrent protection occurs during acceleration, the motor can not start normally. When the motor is lightly loaded Or moment of inertia is more serious. Common frequency inverters are equipped with the function of frequency hopping. Users can set the cross-hopping and cross-hopping widths on the VPf curve according to the frequency of oscillation of the system. When the motor accelerates, you can automatically skip these frequency segments to ensure the system can work normally.
(2) The torque output capacity of the motor is not enough. The factory parameters of different brands of inverters are set differently. Under the same conditions, the load capacity may be different due to different control methods of the inverter, resulting in different loading capacities of the motors; or Due to the different output efficiency of the system, resulting in load capacity will vary. In this case, you can increase the value of torque boost. If it can not reach, you can use manual torque boost function, do not set too large, the motor temperature increase at this time. If still not, should use the new control methods, such as Hitachi inverter VPf ratio of a constant method, start less than the requirements, the sensorless space vector control instead, it has a greater torque output capability. For fan and pump loads, reduce the torque curve.
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Fourth, the inverter and PC debugging
Inverter connected to the host computer for system debugging After the basic setting of the manual is 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 change the operation mode of the inverter to terminal control . According to the needs of the host computer system, set the range of the receiving frequency signal terminals of the inverter to 0 ~ 5V or 0 ~ 10V, and the response speed of the inverter to the analog frequency signal sampling. If you need another monitor header, select the monitor output of the analog output and adjust the range of the monitor output terminal.
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