Consultation on selecting a 22kw inverter for a 22kw motor
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This post was last edited by Xiāoyáo Ténglóng on 2016-9-2 at 17:39. Hello, all electrical engineers! I’ve run into a problem recently and would like to ask for advice. For a 5-liter reaction kettle, a stirring motor of 22 kW was selected due to the high viscosity of the medium. Now, an inverter needs to be installed for speed control and soft start; Fujitsu inverters must be used for this purpose. I would like to ask whether a 22kw motor requires a 22kw frequency converter What to do if the inverter triggers protection due to the medium being too viscous? I found the RN22G1S-4C model of inverter when looking for a suitable option; I’m not sure if it will work Is it necessary to opt for a 30kw inverter? Also, can such a large frequency converter be placed directly in an explosion-proof enclosure on site? Will it affect heat dissipation? I’ve seen explosion-proof boxes used to house frequency converters, but I’m not sure whether frequency converters of this size can be placed in such boxes I would be extremely grateful if experts could give me some advice!
For applications with high starting loads, it is recommended to use a constant-torque frequency converter; choosing a model with slightly higher capacity is also an option. It is not appropriate to place the frequency converter in an explosion-proof box, as such boxes are completely sealed, while the frequency converter needs ventilation for heat dissipation.
It is recommended to place it in a non-explosion-proof area. If it must be installed in an explosion-proof box, it’s possible to increase the size of the variable-frequency cooling fins; however, other modifications are required, which is a bit troublesome. If you are not deterred by the high price, choosing a larger model of inverter comes with many advantages.
Dear sea friend, I suggest that you first consult a technical book on frequency converters as a reference. I recommend a good book to you: \"Variable Frequency Drives: Engineering Applications, Electromagnetic Compatibility, Fault Diagnosis\", edited by Zhou Zhimin, Zhou Jihai, and Ji Aihua, published in December 2005. Additionally, it should be briefly explained that when selecting an inverter, the following requirements should generally be met: 1. The voltage level must match that of the drive motor ； 2. The rated current is approximately 1.1 to 1.5 times the rated current of the drive motor ； 3. Select the control mode of the inverter based on the mechanical characteristics of the driven equipment. In particular, for this type of mixer load, it is necessary to select a higher power level based on the actual conditions (sometimes even an increase of two gears is required) ； Attention must also be paid to the distance between the inverter and the motor of the on-site mixer; if this distance exceeds 100 meters, measures should be taken during the design phase to mitigate the effects of the coupling capacitance to ground. It is advisable to select an inverter with a capacity that is one or two levels higher, and installing an output reactor at the inverter’s output end is the preferred solution. In short, choosing an inverter isn’t something that can be decided in just a few words; it requires a solid technical foundation, otherwise it will definitely lead to mistakes. It’s recommended to find some books to study this topic!
In fact, you just need to determine whether the 22KW mixing motor is capable of handling the mixing task; if it is, then there’s no need to upgrade the frequency converter. If you think you might switch to a larger motor in the future, you could choose to upgrade the frequency converter to a higher capacity model. Also, there is no need to install the frequency converter on-site; a flameproof speed control box at the site will suffice, which saves costs and makes maintenance easier