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Is 4x2.5 mm Cable Sufficient for an 11 kW Motor?

kiecio 54081 35
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Treść została przetłumaczona polish » english Zobacz oryginalną wersję tematu
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  • #31 5402367
    JK60
    Level 14  
    Daj wrote:

    And I don`t agree with the suggestion JK60 replacing the fuse behind the meter with a slow-blowing C25 fuse because there is such a thing as gradation of protections and why do you need two C25s one after the other and you never know which one will work first.

    Redundant with B25 characteristics for an 11kW motor?
    And what is the selectivity now - before the C25 counter, after B25?
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  • #32 5407966
    kiecio
    Level 11  
    Today I finally started this engine under full load (two circular saws in wood) and it turned out that it has absolutely no power, it stops on thin rolls of material (wood) and, what is important, it does not eject the fuses, it only stops when under load :/ will it be Is it the fault of the cable which, as I wrote earlier, is 20m 4x1.5mm and 30m 4x2.5mm?
    And one more question for my friend @Daj, are you sure a 25A switch is enough because today in the store a guy argued with me that 40A is the minimum? ?
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  • #33 5408046
    marian_em
    Level 25  
    Start by measuring the voltage at the terminals while the engine is under load. Then measure the voltage at the beginning of the first cable (or preferably at the first protection in the switchgear) and you will know how much is lost along the way.
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  • #34 5417606
    00marian00
    Level 11  
    Hi,

    as for the low power, it may be caused by the fact that when you connect this motor in a star, you have 1/3 of the power, the next reason is the low supply voltage. Torque on the motor: M = flux x current, flux depends on voltage, so with star connection and reduced voltage, the motor power will be approximately 1/4 of the power. Also, only a triangle connection gives a reasonable solution, the power will not be maximum anyway. And I would also choose 4x4 wires.
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  • #35 5417638
    Daj
    Level 14  
    As I wrote earlier, I was wrong when I said that you can use the "2 times" boot, I corrected my previous post.

    This motor is not suitable for Y/Δ starting because it must operate in Y with a phase-to-phase voltage of 400 V, so switching it to Δ will cause it to burn out because the motors were designed for a voltage of 290 V.

    And its lack of power is caused by voltage drop on too thin wires
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Topic summary

The discussion centers around the suitability of a 4x2.5 mm cable for powering an 11 kW motor. Responses indicate that while a 4x2.5 mm cable may suffice for short distances (up to 50 meters), a larger cross-section, such as 4x4 mm or 5x6 mm, is recommended to accommodate starting currents and ensure safe operation. The necessity of a fifth wire for grounding (PE) is debated, with some asserting that only three phase wires and a ground are needed. Concerns about voltage drop and the motor's operational characteristics when connected in star or delta configurations are also highlighted. The importance of proper cable sizing based on distance, load, and installation conditions is emphasized, with suggestions for using protective devices and ensuring adequate current ratings.
Summary generated by the language model.
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