Page 6 of 6 FirstFirst ... 456
Results 101 to 105 of 105
  1. #101
    Join Date
    Jul 2012
    Location
    Bertie County,NC
    Posts
    870

    Default Re: For those who build your own, which table saw?

    Quote Originally Posted by Acebird View Post
    Mechanical power is torque times speed. Electrical power is current times voltage. So to simplify you can think of current being the torque factor and voltage being the speed factor.
    For a DC (direct current) motor amps relates directly to torque almost exactly. It is practically a straight line curve. An AC motor doesn't follow exactly because there is frequency involved but it does follow in the portion of the curve around the stated RPM of the motor. It is only when you pull the motor down (out of phase) that bad things happen. Variable speed AC drives (inverters) work by changing the phase and voltage. In so doing the HP varies with the speed. For the most part any AC motor can be variable speed by using an inverter (AC drive).
    ok?

  2. #102
    Join Date
    Nov 2011
    Location
    Rader, Greene County, Tennessee, USA
    Posts
    6,191

    Default Re: For those who build your own, which table saw?

    > Variable speed AC drives (inverters) work by changing the phase and voltage.


    Variable speed in an induction motor is accomplished by varying frequency, not phase.

    And in a variable frequency drive (VFD) induction motor, an inverter is indeed part of the process, but an inverter simply converts DC to AC. If the supply power is AC to start with, then there is also a rectifier to convert the AC to DC, and a controller to set the appropriate frequency for the AC output of the inverter at the frequency needed for the speed desired.

    In VFD drives the inverter needs to be designed to output AC power at a variable frequency called for by the control circuitry, which will vary as the desired speed of the motor varies.

    In ordinary inverters such as those that you might use with 12 volt car batteries the AC output frequency is fixed at 60 hz to match residential line power.

    It does seem unlikely that any Beesource members will encounter a tablesaw with a variable speed induction motor!
    Last edited by Rader Sidetrack; 01-25-2014 at 09:19 AM.
    Graham
    USDA Zone 7A Elevation 1400 ft

  3. #103
    Join Date
    Sep 2011
    Location
    Reno, NV
    Posts
    3,012

    Default Re: For those who build your own, which table saw?

    My make it myself factor may have altered drastically. I met a guy yesterday that has over 20 years either running or owning his own sugar pine mills. I started talking to him about getting in contact with some of them in regard to purchasing end mills. he asked me how long. when I told him the longest piece in a hive is 20 inches. he sort of rolled his eyes and smiled. then he said he can get truck loads of that stuff. random widths though. Btu if it drops the cost of the lumber as much as I think it can. Commercially made boxes may never be on my list again.
    Stand for what you believe, even if you stand alone.

  4. #104
    Join Date
    Sep 2007
    Location
    Hudson, WI USA
    Posts
    2,205

    Default Re: For those who build your own, which table saw?

    Daniel, as I recall, that is exactly how Michael Palmer gets his lumber.

  5. #105
    Join Date
    Mar 2011
    Location
    Utica, NY
    Posts
    9,546

    Default Re: For those who build your own, which table saw?

    Quote Originally Posted by Rader Sidetrack View Post
    > [COLOR=#333333]
    Variable speed in an induction motor is accomplished by varying frequency, not phase.
    You are correct, I used the wrong term.
    Brian Cardinal
    Zone 5a, Practicing non-intervention beekeeping

Page 6 of 6 FirstFirst ... 456

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Ads