Furnace blower into garage shop fan?

Discussion in 'Home Repair' started by Oren, Mar 16, 2012.

  1. Oren

    Oren Guest

    I'm converting a HVAC furnace blower fan (c1997 model) into a garage
    shop fan. Salvage from my house. There are no markings, labels, etc.,
    on the motor for information. I know nothing about the motor other
    than four speeds.

    Pic sample: (like this)


    The black wire is high speed, the blue wire is low-high speed. The
    red and orange wires are high-low or low speed (have not yet connected

    The high speed (black) gets hot as does the extension cord plugs and
    the metal cowling. Putting bigger gauge cords on I still get heat on
    the cord, 12 gauge (25'). Same with the blue wire, but not as hot
    (metal cowling cool) or as much heat on the cord.

    My next try is the high-low speed, same 12 gauge extension cord (25').
    Then try the other speed, low, on the same cord.

    The motor has a start capacitor; the motor runs fine. Heat on the
    cord is what I want to eliminate.

    Any thought on using the high speed without the heat problem?

    If I have to, I can settle for the lowest speed, but prefer the higher
    speed (desert hot garage).

    Ideas and help appreciated.
    Oren, Mar 16, 2012
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  2. Oren

    RBM Guest

    What is the amperage and voltage of the blower?
    RBM, Mar 16, 2012
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  3. Oren

    Oren Guest

    Voltage is 110 AC. No idea on the amps of the motor. No marking or
    indication of amps.
    Oren, Mar 17, 2012
  4. Oren

    DanG Guest

    Oren, a furnace fan is normally in a closed structure and the air flow
    is restricted by opening sizes. RBM asked you about amp draw as this is
    what you need to NOT exceed or you will toast your motor soon. I've
    made quite a few of these for different people/reasons. You'll be
    really close if you close off one side of the fan with a piece of peg
    board, the other side can remain full open. The amp draw will be really



    Keep the whole world singing . . .
    Dan G
    remove the seven
    DanG, Mar 17, 2012
  5. Oren

    gregz Guest

    Restriction should lessen amps.

    gregz, Mar 17, 2012
  6. Oren

    Oren Guest

    Would I use peg board on the opposite side of the motor mounts as in
    the photo above? I can fashion something like that. I've yet to
    reduce the speed using the red / orange wires which is low-high /
    low, respectively.
    Oren, Mar 17, 2012
  7. Oren

    krw Guest

    Um, maybe measure it? ;-)
    krw, Mar 17, 2012
  8. Oren

    Oren Guest

    Using this idea to restrict the air flow into the blower, could I get
    / go back to the high-speed (black wire) that I prefer?

    Eventually this fan will be on a small dolly that I can wheel around
    and use in various situations. Hopefully, have an on / off switch.

    Also I would use hardware cloth to keep my fingers safe :-\
    Oren, Mar 17, 2012
  9. Oren

    Oren Guest

    Gosh dang it, now I need another tool. I'm dangerous when it comes to
    electrical work. My policy is keep one hand in my pocket (G).
    Oren, Mar 17, 2012
  10. Oren

    krw Guest

    Got $12?

    Good policy, but if you were a real klutz you'd keep two hands in pockets.
    krw, Mar 17, 2012
  11. Oren

    Oren Guest

    I'm kicking myself now. I had a perfectly good clamp meter that sit
    for years (decades), that I only used once. Sold it in a yard sale and
    now regret doing so. Off to clip my HF 20% coupons. Thanks.

    I do regret selling the meter I had. Can't borrow one from neighbors.
    Oren, Mar 17, 2012
  12. Oren

    Paul Drahn Guest

    What you have is a standard furnace blower. I have the identical
    fan/motor on my heat pump. I also found an identical blower a few years
    ago in the metal bin at the local transfer station and snagged it to use
    as a cooling fan for my business.

    The capacitor is not a starting capacitor. It is in series with one
    winding of the motor and is there all the time. The motor actually has 5
    windings. Select one of the other 4 for speed control.

    The heat problem is because the bearings are dirty and resist the fan
    from running at the selected speed. Take it apart and clean it all. Then
    either check the capacitor, or just replace it. They are common and
    available on Ebay.

    When clean and lubricated and with a good capacitor, the fan will run
    forever without getting hot.

    For the plant cooling fan, I covered the sides of the squirrel cage
    openings with plastic mesh material to keep fingers and trash out of the
    fan. I also built a steel stand with a pair of wheel to make moving it
    around much easier.

    I also found a rotary switch I could modify to allow selection of either
    off or any of the 4 speeds. People almost never run it at high speed.
    Blows TOO much air!

    Good luck

    Paul Drahn, Mar 17, 2012
  13. Correct, the current will drop because the motor is doing less work. ^_^

    The Daring Dufas, Mar 17, 2012
  14. If you put it on wheels, make sure they have locks on them or make some
    little wheel chocks. ^_^

    The Daring Dufas, Mar 17, 2012
  15. Oren

    DanG Guest

    Oren, with the peg board on one side, you sure can use the high speed or
    any speed for that matter. The reason the cord was getting hot had to
    do with excessive amp draw when the motor was allowed to run
    unrestricted. The peg board is easier to mount on the side that does
    NOT have the motor hanging on it. YOu will probably want to handle of
    some type on the top as they are top heavy. It is really easy to mount
    a handy box on the outside corner of the fan (pay attention to not
    getting a screw in the fan cage). You can mount a multi speed switch or
    simply a light switch for simple off and on. Be aware this is not a UL
    approved assembly. Common sense and reasonable care on assembly will
    give you a usable tool.

    Measuring the amp draw of the unrestricted motor will not give you
    useful information if you do not have the design amp draw for the motor.



    Keep the whole world singing . . .
    Dan G
    remove the seven
    DanG, Mar 17, 2012
  16. Oren

    JIMMIE Guest

    May be why its not used in a HVAC unit anymore

    JIMMIE, Mar 17, 2012
  17. Oren

    JIMMIE Guest

    I used to use oe of those I mounted it in a plywood bood thaat held 4 big air filters. I would run it when I was doing something that made a lot of dust. Really helped to keep the shop clean.

    JIMMIE, Mar 17, 2012
  18. Oren

    Han Guest

    I'm still using one of those. I bought a squirrel cage fan off Ebay(when
    I got it, it was suitable for a raccoon), and built a box around it. I
    use 2 sets of doubled-up 18x25"filters on it. Very nice, and quiet too.
    Han, Mar 17, 2012
  19. Oren

    trader4 Guest

    I'm down with the above. If 25ft of 12 gauge is getting
    hot, something isn't right. Assuming of course this is a
    typical home furnace blower. They only typically run a
    15 amp circuit to the furnace, which means 14 gauge
    should be plenty.
    trader4, Mar 17, 2012
  20. Oren

    krw Guest

    Do the coupons work on sale items? Got any? I'm trekking down to Montgomery
    to buy a tile saw tomorrow. The two models I'm interested in are already on
    sale, but another 20% would pay for the gas. ;-)
    Well, if you'd bring it back... ;-)
    krw, Mar 17, 2012
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