NGC Home Wiring

[screamday]

I have a home wiring question for the collective. I have a whole house fan, similar to the one in the picture below, that was installed new in a recent addition.....about two years ago. I'm curious about the wiring configuration shown in the diagram. The fan is a two speed unit with two switches. The fan I have will not start correctly on the low setting. If I turn the fan on and the speed switch is set to low, the fan will struggle to turn. If the speed switch is set to high when I turn on the power the fan will get up to speed immediately and I can then switch to low.....which works.

I was wondering if someone can explain, in "You idiot, it works like this" terms, how this switch configurations works to adjust the speed. The reason I ask, is one, why  the fan won't turn on in low speed and two, I believe the motor has sh&* the bed in the last couple of days. It started making a lot of noise and the other night it shut down by itself.....not completely shut down, but shut down as if I was trying to start it at the low speed. So I turned it off and haven't used it since.

I have not checked to see if it is wired correctly.....accor ding to the diagram. I will probably take the motor out and see if I can have it tested by a local shop.

Thanks!!

[oldbike54]

 W/O getting into specifics , it is simply a matter of lower amperage on the low speed setting .

 Did the fan turn on set on low before the problem arose ?

 Dusty

[Testarossa]

Most electric motors pull a brief amperage spike at start-up and your low setting isn't pushing enough current to overcome that spike. Dunno about the noise.  Is it an electrical hum or a mechanical ticking/clanking?  If the latter, suspect a bad bearing. Also check condition of brushes if any.

[RinkRat II]

   A couple of possibilities, Motor could be bad. If there is a capacitor on the motor it may be bad. Looks like a battery and helps the motor on startup. Motor shop can check both.  I would check the breaker, switches,  and wiring first, are you getting a full 110 volts from the breaker?
 Wiring diagram you show is fine, switch on left just connects and disconnects power to the two speed switch on the right, motor should start in either hi or low position. Disconnect hi/lo switch and check continuity through hi and low connections.   Keep us posted......

    Paul B

[ITSec]

A good test is to turn it on on low, then use a stick (no, NOT your hand!) to turn the blades and see if it starts going on its own. If this can get it going (just as starting on high and then dropping back t low), the motor is having trouble overcoming failing bushings or a similar condition. Some people use a supplemental or boosted capacitor of some kind to boost the starting voltage and get the thing going, but that's a temporary fix to a permanent failure. As Paul noted, there may be an existing capacitor on motors designed for this (frequently used on AC heat exchangers for example) and that's another possible point of failure if it exists.

If this test can get it going, your motor (or capacitor if it exists) is on its way to total failure and needs a repair/replace.

[oldbike54]

 If there is a capacitor in the system that is where I would start . Do be careful with it , some will store energy for several hours .

 Dusty

[screamday]

Did the fan turn on set on low before the problem arose ?

 Dusty

No....it has always had a problem starting on the low setting.

Is it an electrical hum or a mechanical ticking/clanking?  If the latter, suspect a bad bearing. Also check condition of brushes if any.

Tinking/clanking.....bearing or brushes was my first thought. The bearings at the blade shaft seem to be ok, but I will have to take it apart to be sure.

   A couple of possibilities, Motor could be bad. If there is a capacitor on the motor it may be bad. Looks like a battery and helps the motor on startup. Motor shop can check both.  I would check the breaker, switches,  and wiring first, are you getting a full 110 volts from the breaker?:

There could be a capacitor in the little black box on the side of the motor. Checking the voltage should be easy, I'll check that first.

Thanks guys.....this is a good start.

[rodekyll]

Just a thought -- I have heater fans that use "high" as the first switch position, and then you continue turning the switch for lower speeds.  these have no starter capacitors, so they begin with full power to get he fan spinning.  Could it be that "high" is the normal first position for your fan?

[screamday]

Just a thought -- I have heater fans that use "high" as the first switch position, and then you continue turning the switch for lower speeds.  these have no starter capacitors, so they begin with full power to get he fan spinning.  Could it be that "high" is the normal first position for your fan?

Maybe.....but then why the High/Low switch? I just ass-u-me-d that meant it would start on either setting. I know what your saying....I had a shop fan that you started at the high position and kept turning to get to the low position.....one switch/dial.

[Wayne Orwig]

I would suspect:
A weak capacitor
or
Bad motor bearing
or
Bad fan bearing
or
bad (tight) belt
or
a few turns shorted in the motor (toasted)

[screamday]

Still haven't got this figured out. I took the motor to a shop to have it tested and the motor worked fine on the bench....high and low speeds. My next line of focus is the high/low switch. I want to replace it but can't find anything similar at the usual local brick and mortar stores.....includin g electrical supply stores. So, my question.....is the high/low switch just a common 3-way switch or is there more to it? Even the guy at the electrical supply store didn't know....which I found odd. I can buy a 3-way switch anywhere. 

[RinkRat II]

 As long as your motor connections look like this


how do i upload images to the forum

 You can get a two speed switch a home depot or lowes that looks like this


 Direct replacement and should be straightforward. May have to look in their cooler aisle to find it .

   Paul B

[screamday]

  You can get a two speed switch a home depot or lowes that looks like this


 Direct replacement and should be straightforward. May have to look in their cooler aisle to find it .

   Paul B

Ya, I tried Home Boy and everyone I talked to at the store went to a blank stare. One guy sent me to the electric supply store.....where I got more blank stares. If you feel it's not the same as a 3-way light switch, I guess I'll just order one online. Trying to salvage some of the great weather we're having.

[RinkRat II]

 Internally it's a single pole double throw switch, I'm surprised of the difficulty to get one.  Any Air Conditioning supply houses nearby?
 
     Paul B

[screamday]

Actually.....that switch from HD is not a direct replacement. The one I have does not have the OFF position in the middle of the switch. That function is handled by a separate switch.

[RinkRat II]

 I guess to answer your original question, yes it is a three way switch. You could swap the red and black leads on that switch to see if it is indeed faulty or if it still has trouble starting on low. Keep us posted.

 Paul B

[normzone]

No real assistance in this post, but EVERY box fan I've ever bought has mention in the instruction set to start it on high and then adjust it.

I suspect that is because of the technical advice above regarding spikes and loading requirements and .... other technical stuff.