Need to pay attention to the use of the inverter - Database & Sql Blog Articles

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1. The ambient temperature has a great influence on the service life of the inverter. When the ambient temperature is 10 °C per liter, the life of the inverter is halved, so the problem of ambient temperature and heat dissipation of the inverter must be solved.
2. Correct wiring and parameter settings. Be sure to read the manual carefully before installing the inverter, master its usage, precautions and wiring; after installation, set the parameters correctly according to the use.
3. Pay attention to the relationship between speed and head. The choice of the motor and its optimal working segment are important issues. If the inverter runs below 5HZ for a long time, the motor heating becomes a serious problem.
4. V/f control belongs to constant torque adjustment. The vector control increases the output torque of the motor in proportion to the square of the voltage, thereby improving the output torque of the motor at low speeds.
5. If the system is operated by the power frequency/frequency conversion mode, the interlock of the power frequency output and the frequency conversion output should be reliable. Moreover, the pump should be stopped, the power frequency/frequency conversion should be stopped, and then the contactor should be operated. Since the contact sticking and the extinguishing of the large-capacity contactor arc take a certain time, the order and time of the above switching should be considered comprehensively.
6. The problem of external control signal failure. Generally, there are several cases: the signal mode is incorrect, the terminal wiring is incorrect, the parameter setting is incorrect, or the external signal itself has a problem.
7. The difference between overcurrent trip and overload trip. Overcurrent is mainly used to protect the inverter, and overload is mainly used to protect the motor. Because the capacity of the inverter sometimes needs to be increased by one or two gears than the capacity of the motor. In this case, the inverter does not have to overcurrent when the motor is overloaded. The overload protection is carried out by the electronic thermal protection function inside the inverter. When the preset electronic thermal protection is used, the “current take-up ratio”, that is, the ratio of the rated current of the motor to the rated current of the inverter should be accurately preset.
8. Interference problems.
(1) Good grounding. The grounding wire of the high-power control system such as the motor must be reliably grounded through the connection bus. The control system is preferably grounded independently with a grounding resistance of less than 1 Ω. The sensor, I/O interface shield is connected to the control ground of the control system.
(2) Add EMI filter, common mode inductor, high frequency magnetic ring, etc. to the input power supply such as the instrument.
(3) Adding EMI filter to the inverter input can effectively suppress the conducted interference of the inverter to the power grid. Adding input AC and DC reactors can improve the power factor and reduce harmonic pollution, and the comprehensive effect is good. When the distance between some motors and the inverter exceeds 100m, it is necessary to add an AC output reactor on the inverter side to solve the leakage of external leakage caused by the leakage current protection caused by the distribution parameters of the output wires to the ground.