To know how to set the parameters of a frequency converter, we must first understand what a frequency converter is and what to do with it.Frequency converter is used to adjust the asynchronous motor speed of a power supply device, according to the rotational speed n = 60 F/p (1 - s) this formula, the inverter is the essence of output frequency adjustable voltage source, by changing the power frequency to change the motor speed, and the frequency change at the same time, in order to avoid magnetic flux saturation cause motor overheating, also follow change voltage, also is to maintain a constant V/F ratio, so the inverter parameter Settings, is around this core.
Motor related parameters
Frequency converter is for the motor service, frequency converter and motor to be used, that is, the rated voltage and rated power of the two are very close.In the process of motor running, it is necessary to set some relevant protection parameters to avoid excessive current and heat burning.Rated voltage: although basically the motor voltage controlled by inverter in China is three-phase 380 volts, it is not excluded that some imported equipment is special. When changing the inverter, we should pay attention to it. For example, the voltage coming in from Japan may be three-phase 220 volts.
Rated current: the motor nameplate has this parameter, the corresponding input is good.Overload protection: this is actually the parameter to control the maximum power of the moment, usually 110%, can be increased to 150%, depending on the actual situation.Overcurrent protection: this is the maximum instantaneous output current, such as 150%. If you are worried about motor problems, you can set it to 100%.Upper limit frequency: 50HZ is generally used in China, but overfrequency is needed in some occasions, such as the spindle of some machine tools, which may be 75HZ earlier. It should be selected according to the working condition, but it should not be too high, otherwise the motor bearing cannot bear.Starting frequency: the frequency converter is usually unable to output very low frequency to drive the motor, which is usually higher than 0.5HZ when starting.
Power supply parameters
Torque improvement: automatic and manual modes are available. If the automatic mode is not effective, manual mode can be selected. In essence, V/F ratio is set.Torque enhancement: considering that the torque of the motor is insufficient at low speed, the voltage value needs to be increased in some occasions. This is the so-called torque enhancement, but it should not be increased too much, otherwise it may be unstable.Acceleration and deceleration time: theoretically, the shorter the acceleration and deceleration time of frequency converter is, the greater the fluctuation of motor current and voltage will be. However, in many cases, the shorter the acceleration and deceleration time of motor is, so it needs to be set according to the load.Control mode: general load use V/F mode is good, if it is vector control, you can choose non-inductive vector or inductive vector, depending on the control accuracy to set, if the selection of vector control, also need to do parameter adaptive adjustment.
Man-machine control parameters
The frequency converter should be controlled and operated by people, such as starting it, stopping it, making it run fast, slowing it down and so on.Start source: this includes the start and stop function, if through I/O control, you can choose the corresponding I/O port, most frequency converters are fixed a certain I/O, also can set the panel, some even communication mode to control.Frequency source: the same as the starting source, but the frequency source is often in the form of analog quantity, voltage and current form, there are some occasions through multiple I/O to achieve multi-segment speed control, also have communication mode to complete.Display class: on the panel can switch display current, voltage, frequency or speed and other parameters, depending on the need.