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Thread: VFD and speeds

  1. #1

    Default VFD and speeds

    O,K,
    went and got all my wireing,switches,ect,ect,
    (ready to blow myself acrost the room holding a melted screwdriver again,,,,)

    How arey you guys figuring your speeds at the bit,???

    do you use the VFD digital readout??

    For example--
    if the VFD is showing (number)
    bit speed equals--?

    VFD X pully setup ?
    VFD - pully setup ?

    EI,

  2. #2
    Join Date
    Apr 2001
    Location
    Maine
    Posts
    7,010

    Default

    With my VFD, it can be set to display either Hz, RPM, or something else I don't recall offhand. The RPM value can be jiggered with a correction factor to make it correspond to one's particular machine.

    For a while I had it displaying Hz, and I had a chart taped to the milling machine to relate Hz + pulley step to RPM. Then I realized that with the VFD I keep the belt on one pulley step virtually all the time, so I reset the VFD to display the RPM corresponding to that pulley step. The only time I use a different pulley step is when I want a really low RPM, and for those times I don't worry about the reading, I just set the speed to what seems right. (Which is basically what I do most of the time, anyway).
    ----------
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  3. #3
    Join Date
    Feb 2007
    Posts
    379

    Default

    I went the Hz readout & laminated chart route as even with a VFD I find it useful to use the six gears on my mill's head. 10, 20, 50 and 100 Hz seems all that's really necessary, it's easy to fill in the gaps with mental arithmetic,
    Regards,
    Nick

  4. #4
    Join Date
    Oct 2002
    Location
    Bremerton Washington
    Posts
    5,792

    Default

    My VFD's display only frequency. I do a little head math (lessee 45 Hz is 3/4 of 60 Hz so 3/4 of 213 RPM is...) get the RPM. A table or a graph on the wall helps. I usually go by chip color anyway.

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