Results 1 to 3 of 3

Thread: Exhaust Motor

  1. #1

    Smile Exhaust Motor

    Was asked me to connect a blower fan (not un-like a rather medium sized blower wheel from a 5 Ton A/C air-handler. I suspect that is exactly what it is!!? It is being utilized to exhaust air to the outside for a bed-room, installed about 8 feet high in a small open loft of sorts. The previous owner has removed the control switch for some reason. The motor has a black, a red, and a white wire ( 12 awg). I did confirm the operation of the motor. White to black =13 amps. White to Red= 9 amps. Can I safely hook up this motor via a new switch? I don't have access to visibly see the nomenclature plate for the motor. There is no duct system, the fan just expells the air directly to the outside.(out-side wall cut-out) If this is indeed just a A/C blower motor/wheel that the previous owner installed, might there be the possibility of a run-away motor speed effect of any sort. (being without any duct system, hence no static pressure. thanx in advance.
    Last edited by sidecutter; April 29th, 2015 at 02:45 PM. Reason: spelling

  2. #2
    Join Date
    Dec 2003
    Location
    Kent, WA
    Posts
    8,482

    Default

    Speed is most likely fixed if an induction motor is driving it, but it seems this motor has some speed taps so not sure what type it is. If it is moving air, there will be static head pressure just from the housing. It should draw less amps than "normal" if the head pressure is lower than designed.

    There are a host of possible issues if you are installing this for pay. If a DIY thing, its his own fault if there's a problem...

    Issues:
    This is a lot of air to be dumping outside. Is that the desired effect (e.g. like a whole house fan)?

    Is there a guard on the intake (don't want any fingers getting chopped off)? How about a filter (may not be needed though)?

    Is there motor overload protection (or is it thermally protected)? The circuit breaker for the branch circuit most likely won't be sized right unless the motor is thermally protected in which case that is the overload device.

    Did you put this on a dedicated circuit (and is it 120V or 240V)?

    Is there anything on the motor such as HP rating? The original motor nameplate info would be good, but with a different (no) duct system the numbers will be different anyway.

    A switch will be fine if marked "AC Only", but I'd go with a 20A switch or one rated in HP if you can find the motor HP. If its a 240V motor, be sure to use a double pole switch and switch both hots.
    Mark
    Kent, WA

  3. #3

    Smile

    Quote Originally Posted by suemarkp View Post
    Speed is most likely fixed if an induction motor is driving it, but it seems this motor has some speed taps so not sure what type it is. If it is moving air, there will be static head pressure just from the housing. It should draw less amps than "normal" if the head pressure is lower than designed.

    There are a host of possible issues if you are installing this for pay. If a DIY thing, its his own fault if there's a problem...

    Issues:
    This is a lot of air to be dumping outside. Is that the desired effect (e.g. like a whole house fan)?
    Yes, the new owner called it a whole house fan. It is however located in the Master Bed-room so will not do much for the whole house really.
    Is there a guard on the intake (don't want any fingers getting chopped off)? How about a filter (may not be needed though)?

    Is there motor overload protection (or is it thermally protected)? The circuit breaker for the branch circuit most likely won't be sized right unless the motor is thermally protected in which case that is the overload device.
    Yes, I am quite certain the motor has an internal over-load.
    Did you put this on a dedicated circuit (and is it 120V or 240V)?
    I will check next time I am there to see what else, if anything is on this certain. Thanx for reminding me of this.
    Is there anything on the motor such as HP rating? The original motor nameplate info would be good, but with a different (no) duct system the numbers will be different anyway.
    Nomenclature plate is, I believe hidden behind the motor bracket. (alas)
    A switch will be fine if marked "AC Only", but I'd go with a 20A switch or one rated in HP if you can find the motor HP. If its a 240V motor, be sure to use a double pole switch and switch both hots.
    Thanx SuePmark for your always generous time.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

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