Fusable links always make me wonder why they failed. Make sure that the fan spins freely.

 

Fusable links always make me wonder why they failed. Make sure that the fan spins freely.

Yeah, bearings (bushings actually) get dirty and the fan begins encountering resistance to rotation. As the motor slows the coils heat up. Because the fan is not able to convert electrical energy into mechanical energy and then into wind energy, that loss of conversion into (ultimately) wind means it has to be converted into heat. Energy can not be created or destroyed; it can only be converted into different forms of energy. And it's the excess heat that leads to the demise of the fusible link.

It's my opinion that the fusible link is likely responsible for a huge reduction in the number of fires caused by stalled fans that cease to convert energy into wind and instead convert it into excessive heat. Without the fusible link many fans would be considered fire hazards for just such reason as bearings binding up.

 

I doubt this is as significant a contributor as what was just so well explained by Tony, but I think that very same wind helps to cool the unit. I noticed that in at least my model the plates holding the shaft (forgive my lack of terminology. I'm new at this.) were staggered, such that by spinning, they would promote the movement of air through them. Somebody let me know if I'm wrong.

 

@Wildlife Engineer 1) Welcome to AAC. 2) Yes, you're right, air movement through the fan also promotes stripping heat away from the motor.

It's a fact that a stalled motor will heat up excessively. A motor that spins with no load on it will get warm but will not heat up to the point where it might start a fire. Fans DO keep their motors cool. So slowing down a fan and the heating of the motor is worsened by the lack of airflow through the vents. That and the buildup of dust, which can also be a huge contributor to excessive motor heating, and possible blowing of the fusible link.

 

Thank you! My first semester professor told me that the quickest way to burn out a motor was to give it just enough current not to spin. Now it makes sense why!

 

I’ve rescued many a fan from the side of the road. I think I’ve only ever bought one fan.

Dried bearings are the #1 culprit. While not an electrical solution, this process has revived many a fan.

With no power anywhere near the fan, I flood the bearings with alcohol. I manually spin the shaft, until the flooding of the bearings runs clear. Then I let it dry and lubricate with motor oil. Apply with a thin metal shaft. A finish nail works well. Dip the nail into a small cup of oil. Like a 4 oz bathroom cup. With the fan on its side, drip oil into the bearing with the nail, spin and repeat. Then turn the fan over and oil the other bearing.

 

Even better than automotive motor oil may be the straight weight #30 oil, less likely to damage the windings if it gets on them. And the older automatic transmission oils have less tendency to soften plastic bearings. I have one old box fan that I have re-lubricated several times. It fits in the one window very well, and I need to take care of it because I doubt that I would ever find another just like it. The more recent box fans have far more rounded corners, not nearly as good in a window.

 

older automatic transmission oil

That's my favorite way of cleaning bushings that have dried and caked up. I used to use WD-40 but that doesn't have lasting properties as a bushing lubricant.

I, too, miss the older box fans; they DO fit better than the newer ones. Years ago I had a reversible three speed box fan. That's something you never see anymore. Living in Utah, most common form of cooling a house is a swamp cooler (evaporative cooler). With traditional AC you close up the house and recirculate the air over and over cooling it as you go. This tends to dry out the already dry air, but some people prefer AC over a swamper. I like the swamper because it adds humidity to the air, and, unlike traditional AC, you actually OPEN windows so that the swamper can push cold air into the house. You regulate the temperature in each room by how much you open the windows. However, open it too much and all you're doing is directing the cool air outside and the rest of the house doesn't get nearly as much cooling.

This is originally a very old thread. Perhaps @Wildlife Engineer, the person who revived this thread may want to post a new thread of their own so we can address his need directly.

 

That's my favorite way of cleaning bushings that have dried and caked up. I used to use WD-40 but that doesn't have lasting properties as a bushing lubricant.

I, too, miss the older box fans; they DO fit better than the newer ones. Years ago I had a reversible three speed box fan. That's something you never see anymore. Living in Utah, most common form of cooling a house is a swamp cooler (evaporative cooler). With traditional AC you close up the house and recirculate the air over and over cooling it as you go. This tends to dry out the already dry air, but some people prefer AC over a swamper. I like the swamper because it adds humidity to the air, and, unlike traditional AC, you actually OPEN windows so that the swamper can push cold air into the house. You regulate the temperature in each room by how much you open the windows. However, open it too much and all you're doing is directing the cool air outside and the rest of the house doesn't get nearly as much cooling.

This is originally a very old thread. Perhaps @Wildlife Engineer, the person who revived this thread may want to post a new thread of their own so we can address his need directly.

When I lived near New Orleans dryness was not a problem, in fact it was unknown, mostly. There were days with condensing humidity, which must be experienced to be understood. Fans were handy most of the time, but hot wet air is not very refreshing. Now in southeasern Michigan, the climate is way different.

 

New Orleans dryness was not a problem

Wasn't a problem in Huston either.

One summer evening the temperature dropped down to 70 degrees F. Thought it would be a good time to open the windows and let some fresh air into the room. That was like opening a hatch on a submerged submarine. Within minutes I had all those windows closed and the AC back on. Summertime electricity bills were anywhere from $1500 to $3000 a month. Fortunately that didn't last long, typically three months out of the year.

Living in Utah is a stark difference from living in airborne water. Summer time temperatures in Houston rarely got above 95 whereas in Utah, summers can reach 110 on rare occasions. Also spent some time in Wisconsin where winter temps (as seen recently) can be painfully cold while in Utah today is described as the coldest day this year; 15 degrees F. (I know - poor me)

In dry climates fans can be quite effective. I have several. An oscillating fan on a stand, a vornado sits on a desk or the floor, box fans, personal fans, computer fans (mostly for smoke evacuation during soldering operations). Fans that came out of microwaves - I have a really cool fan with a squirrel cage in my cabinet. Still don't know what I'm going to do with it but it really moves air for its size. (no figures on CFM or wattage)

I really think if @Wildlife Engineer needs help with something he should open a new thread directly related to his question / problem - IF he has any.

 

I just saw your photos and have the exact switch situation. I am new to this website and am 76 years old, so please be patient. How do you tie the power cord into a 4 position switch? If you have a photo or diagram, I would appreciate it. Thank you.

Lynwood

 

Welcome @Lynwood to AAC.

Typical wiring of such a switch is that you have a neutral line that is tied directly to the common lead of the motor. The other three lines are for the three speeds of the motor. The rotary switch you have will nave one line for the incoming power from the power cord. The other three lines from the motor should go into the remaining three openings. A four position switch consists of position 1 (OFF), position 2 (LOW), position 3 (Medium), and position 4 (HIGH) {assuming it's wired correctly.}

Just remember that the two wires from the power cord PROBABLY should not be put into the switch. However, there are some sorts of switches that do allow for the pass-through of the neutral line. You don't NEED to pass the neutral through the switch. You can connect the two wires (Neutral and Common) by twisting them together then installing the appropriate size wire nut. Then tape the nut in place to prevent it from loosening and falling off, thus exposing potential power to short to the case.

We can't tell you for sure exactly how to wire your switch since none of us have a clear picture of the switch you have. The person who started this thread showed pictures of two different types of switches. So I honestly am uncertain of which switch you actually have. You CAN take a picture and post it. Then we can better answer your question.

One last thing: Coming in on someone else's thread is considered "Hijacking" and is discouraged. You CAN start your own thread and reference this one so others can get a clearer picture of what you're asking. It's advised you open your own thread.

Again, welcome to AAC. Age doesn't matter. Neither does level of knowledge or experience matter. This website is open to ALL who may have a question or perhaps an answer to someone else's question. AAC encourages all to ask their question, even if they think it's a dumb question. A dumb question answered can prevent someone from losing their life or serious injury.

 

One thing that is VERY IMPORTANT is to be certain that you dod not have a switch that connects more than one output at a time, such as light switches, usually one, the other, and both, followed by off. That will destroy any motor in a short time. It is worth checking to be certain that only one is on at a time.
Beware that there are also 3-speed fan setups that include a capacitor. They seem to be a bit different. On quite a few fans, if the failure is not stuck bearings, it may be that the cord has failed from the fan swinging back and forth. That is a common way some folks use them. And the cord flexes until all of the strands break and then the fan is disposed of, when only the cord needs to be repaired. You find that problem with an ohm meter and flexing the cord in that area.

 

@lyndwood See these diagrams.

http://www.ceiling-fans-n-more.com/ceiling-fan-wiring-diagrams-schematics.php

 

It is quite possible that bringing both lines through the switch is done to avoid making an external splice, which needs a crimp-on insulated terminal and an extra crimping operation. And now a question, which is how do you know that the switch has failed? I have not come across failed switches that were not mechanically broken, the failure is almost always elsewhere.
AND, the push-in connections work best if you solder-coat the wires prior to inserting them into the switch. But be certain to not have any solder bumps or blobs, because they will interfere with the correct insertion.