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OT: TEFC motor air flow

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  • OT: TEFC motor air flow

    What is the correct direction of air flow across a TEFC motor.? Air drawn in across fins, or blown across fins. Maybe there's both?
    Nev.

  • #2
    I think the only mode I've ever come across is the centrifugal fan in the cover at one end. Irrespective of running direction, these fans draw air in the end into the centre of the fan and blow it out radially against the cover. This cover is shaped to have a curve which directs the airflow along the outside of the motor housing - with or without fins on it. The airflow is therefore blown over much of the motor surface.

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    • #3
      Originally posted by NiftyNev View Post
      What is the correct direction of air flow across a TEFC motor.? Air drawn in across fins, or blown across fins. Maybe there's both?
      Since the fan is integral with the motor, the correct way is the way they built it. Where is this going?

      Sent from my SM-G900V using Tapatalk

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      • #4
        It's a radial fin centrifugal fan,so air will be pulled in through the center of the fan shroud and blown out over the fins.The fans are uni-directional so rotation doesn't matter.
        I just need one more tool,just one!

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        • #5
          What a mass of confusion! The correct air flow is from the fan along the fins to the drive end. Small motors often have bi-directional fans that work with either rotation. Larger motors( especially 2-pole) often have uni-directional fans that are designed for one rotation only. They are also quieter and more efficient.

          RWO

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          • #6
            Thought the direction was as stated. So now I need to check this motor at work and see why it's blowing out the fan shroud. The boss asked me yesterday what was correct and I wanted to make sure first.
            Nev.

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            • #7
              General rule for cooling air is:

              Cooling air is intended to flow over the provided fins, or surface. Therefore, flow should be in he direction that causes this.

              If air blows OUTof the fan shroud, ir will flow over the motor fins/outside surface. But if it is pulled INTO the fan shroud, nothing is causing it to flow over the fins/surface at the far end of the motor. Therefore, it should blow out of the shroud.

              IF on the other hand, the shroud extended over the length of the fins, THEN it would not matter as to direction, since the air would be forced to flow over he cooling fins either way.

              In a "don't care" situation like that, other considerations determine correct flow. If, for instance, flow one direction would flood a compartment full of electronic circuit boards with hot air from the motor, it is reasonable to assume flow is the OTHER direction. Or if the air mover is a "muffin fan", it is reasonable to assume the fan should not be "cooked" by the hot air, so flow may be into the fan, and out elsewhere (unless there is other evidence).
              CNC machines only go through the motions.

              Ideas expressed may be mine, or from anyone else in the universe.
              Not responsible for clerical errors. Or those made by lay people either.
              Number formats and units may be chosen at random depending on what day it is.
              I reserve the right to use a number system with any integer base without prior notice.
              Generalizations are understood to be "often" true, but not true in every case.

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              • #8
                Had a close look at that today. Fan shroud is half missing because of corrosion. So, air being sucked into the centrifugal fan is escaping, rather than being forced over the motor.
                Nev.

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