Inverter parameter setting steps
1 acceleration or deceleration time
Acceleration time is the time required to rise from 0 to the maximum frequency, and the deceleration time refers to the time required to fall from the maximum frequency to 0. Usually, the frequency setting signal is used to determine the acceleration and deceleration time. The increase in frequency setting is required to prevent overcurrent, limit the falling rate to prevent overvoltage when the overcurrent is accelerated. Acceleration time setting requirements: The acceleration current is limited to the inverter overcurrent capacity, and the frequency converter trip is not caused by excessive displacement. Deceleration time settings are: Preventing the smooth circuit voltage from being too large, do not make the regeneration overflows to make the inverter trip. The acceleration and deceleration time can be calculated according to the load, but in the debugging, it is often taken to set a longer acceleration time according to the load and experience. By starting, the electric motor is observed to have no overcurrent, overvoltage alarm; then gradually increase the speed reduction setting time Shorten, in operation, the alarm is not the principle, repeat the operation several times, it can determine the optimal acceleration time.
2 torque increase
It is also called torque compensation, and it is a method of increasing the low frequency range f / V to compensate for the low-speed torque due to motor stator winding resistors. When set to automatic, the voltage at the time of acceleration can be automatically increased to compensate for the starting torque, so that the motor accelerates smoothly. If manual compensation is used, the preferred curve can be selected by experiments based on load characteristics, especially loaded starting characteristics. For variable torque load, if the output voltage is too high at low speed, the phenomenon of waste of electricity occurs, and even the motor is large when the motor is loaded, and the speed does not go.
3 Electronic heat overload protection
This function is set to protect the motor overheat, which is the temperature rise of the motor in the inverter according to the operating current value and frequency, thereby overheating protection. This function only applies to "one drag one", and when "one drag", it should be installed on each motor.
4 frequency limit
That is, the upper and lower limit amplitude of the inverter output frequency. Frequency limitation is to prevent malfunction or external frequency setting signal source failure, and cause the frequency of the output or too low to prevent damage to the device. Set it according to the actual situation in the application. This feature can also be used for speed limit. If there is a belt conveyor, since the conveying material is not much, in order to reduce the wear of the machine and the belt, the inverter can be driven, and the frequency converter upper limit frequency is set to a certain frequency value. This allows the belt conveyor to operate on a fixed, low operating speed.
Impact of grid quality on frequency converter
In the case of shock load such as electric welding machine, electric arc furnace, rolling machine, the voltage often has a flash; in a workshop, there are multiple inverters and other capacitive rectification loads, the harmonics generated are very good for the quality of the grid. Severe pollution, there is also a considerable damage to the equipment itself, and it is not possible to operate normally, and the damage of the equipment input loop is caused.
1) It is recommended to increase the power factor and quality of the power grid power factor and the quality of the power grid power factor and the quality of the power grid power factor and the quality of the power grid power.
2) The workshop of the inverter is more concentrated, it is recommended to use centralized rectification and direct current busbar power supply. The advantage is that the harmonics are small, energy saving, especially suitable for frequent starting, braking, and motor running in both electro-operating and power generation.
3) Inverter input side plus passive LC filter, reduce input harmonics, improve power factor, high reliability, good effect.
4) Adding an active PFC device on the input side, the effect is best, but the cost is higher.
Changchun Hongbao is an export-oriented enterprise specializing in research, development, production, sales and technical services in power field products.
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