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Whole house fan motor

Discussion in 'Electronic Basics' started by telengard, May 6, 2013.

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  1. telengard

    telengard Guest

    Just recently purchased a house and it has a whole house fan.
    Unfortunately, the folks who installed the A/C disconnected the
    motorized louvers to get into the crawl space a couple months ago and
    I'm not sure exactly how it was wired. In the crawl space there is a
    black (which had a wire nut on it) and bare wire and a white wire
    which looks like it was curled up to not use it (it is not stripped).
    The motor on the louvers has 2 black wires and a green wire.
    Unfortunately, I could not find any documentation on the motor. We
    have 2 separate switches so the louvers are independently controlled.

    Just wondering what the wires on the motor are. The motor is a Dayton
    Motor Shutter Model 2C904 115V 60Hz.

    Any info greatly appreciated.
  2. telengard

    telengard Guest

    Hi Jamie,

    Thanks for the info, I have been shutting off the breaker when working
    with this. I guess I'm surprised that the white wire would be used, I
    guess the A/C guys may have just twisted it up for safety. That must
    be the missing piece, I had tested both blacks to the one black
    (assuming the white was was wrapped up as it was not used).

    And yes, the motor has some kind of arm attached to it w/ a spring.
  3. Jamie

    Jamie Guest

    the two wires are your 120 volt AC lines from the motor..

    in your case, you can connect the black wires from the motor to
    the white and black wire that is capped off..

    the green wire from the motor is the ground which is connected to the
    bare wire you see..

    since there is a wire nut on the black wire, this tells me it could
    be alive or at some point may come alive...
    I would first kill the circuit that supplies that before attaching the
    last black lead from the motor to that one.

    Also, this appears to be a single direction motor, this tells me that
    the shutter drive must not have a stop on it or it just keeps going
    around and around.. Most likely has an eccentric wheel or a wheel with
    an offset swing arm on it.

  4. Tom Biasi

    Tom Biasi Guest

    When you say the white wire was wrapped, is it wrapped with black tape?
    If so it is probably a hot from the switch.
  5. Guest

    When you say the white wire was wrapped, is it wrapped with black tape?
    Sorry, I should have been more precise. The white wire was not stripped, was not in a wire nut, and was coiled up whereas the other 2 wires were straight (for lack of a better term). In other words, it looked like it wasn'tbeing used, or this was done to prevent a short or something, although I would have thought having the dangling black and bare would be just as bad.
  6. amdx

    amdx Guest

    First I'd like to say, I had a home with a whole house fan, and it was
    great on those summer nights in Michigan. Just crack the windows in the
    room about 4" and turn on the fan. Great breeze comes through.

    There may be a reason it is disconnected ( doesn't work?). I would
    first verify operation of the louver controller. I have enough extension
    cords around that I would just wire a cord to it and plug it in. If it
    opens, unplug it and see if it closes.
    If it works, I would then follow the wiring from the motor and see if
    there is a parallel wiring connection that could be connected to the
    louver controller.
    Here is a link that gave me the little I know about electric louvers.

    Please get your own understanding, before attempting repair.

    (istr, my louvers were opened by the draft that came through)
    From what I read, the louver controller opens with power on and closes
    when power is removed.
    The second link refers to the replacement model that Grainger
    recommends for your unit.,d.eWU
  7. amdx

    amdx Guest

    Where's Phil when somebody really deserves abuse?
  8. Yes a new thread is in order. The middle of the circuit is weird. (at
    least to me.) Your moving hand thing is a sure sign of electrostatic

    George H.
  9. Jamie

    Jamie Guest

    The white wire is the other power wire you need to connect one of the
    black wires on the motor to.

    THe only reason it is not protected via a wire nut is because that
    wire ends up being the low side of the circuit, which should be near
    0 volts. But don't take any chances to think it is just a ground wire,
    just because it does connect to the ground back to subpanel.

  10. Jamie

    Jamie Guest

    Kind of curious how that LED is handling the current when you only have
    a .5 ohm R feeding it? Even if that bias on the base was current
    limited, you'll be suppressing the voltage to the battery no more than
    what the LED forward voltage is plus the 0.650 drop from the base and

    As for the noise you maybe seeing, it's possible you are picking that
    up because of the wires hanging all over the place. You most likely have
    lights with ballast circuits in them, they can generate noise, putting
    your hands over the circuit is just using your body to convey the noise

    bjts are grate for acting as R.F. detectors...

  11. ehsjr

    ehsjr Guest

    I would urge you to follow JT's advice. Build his circuit.

    It is easy to add a pass element to get higher current later on.
    Here's an example diagram to give you an idea how it's done:

    Vin ---+----> ------------------+-----------> Vout
    | e\ /c |
    [3R] --- |
    | | ----- |
    | ----- | |
    | Adj [240R] |
    | | | |
    | +----------+ |
    | | |
    [.22uF] / [.1uF]
    | \ |
    | 5K /<---+ |
    | \ | |
    | / | |
    | | | |
    Gnd ----------+---------+----+-------------+

    Current drawn from the 317 causes a voltage drop across the
    3 ohm resistor. When that voltage drop is below about .6 volts,
    the 2955 conducts no e-c current. When the voltage drop rises
    to about .6 volts the 2955 begins to conduct e-c current. The
    more current drawn by the load, the greater the e-c current.
    The e-c current passes around (not through) the 317 so the 2955
    is called a pass element or pass transistor.

    You can also do it with your 3055, but you need an inverting
    stage to its base. See "High Current Adjustable Regulator"
    diagram in the datasheet for the 317 for an example of using
    an NPN pass element. They use 3 195's in that diagram, but
    you need only the single 3055.

    In reading your various posts it seems clear to me that you are
    expending a lot of effort and have a lot of interest in this, which
    is all to the good. But I also see that you are speeding by some
    points where you could benefit by working to understand them,
    rather than passing them by - which is what prompted me to reply.
    No perhaps about it, it is definitely worthwhile. The earlier
    part of my reply suggests how you can do it with parts on
    hand, then later on add a pass element, or, as you mention,
    substitute a 338.
    Well, you may get it to work, but you won't learn why
    it does, or why the previous attempts didn't. It is
    my impression that you are leap frogging some of the
    basics. Sometimes throwing bigger/better/stronger parts
    at a problem is not in your best interests.

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