Author Topic: Thermal Fuse for oscillating fan (Read 14506 times)

BayouBoy · « **on:** July 14, 2018, 11:37:56 pm »

Hi,
I'm new at this fan troubleshooting and wondering if I can help help with a couple of issues. Fan stop working, but blade turns freely manually. Some quick research points to either a thermal fuse or capacitor. I wanted to be sure the attached is in fact the thermal fuse. Is there a way to verify if it needs changing before ordering the part? Also, would I need to find one with the exact printing as on the photo? Any help would be appreciated. Not sure of the fan brand name.. It's a pedestal type.

innkeeper · « **Reply #1 on:** July 15, 2018, 02:34:16 am »

thats a non resettable thermal fuse by aupo, aupo is still in business, and the current model is the a4-f if I am not mistaken
pretty easy to find, even on eBay and other outlets, and are really cheap.

basically, the 2a is the current handling capacity, so certainly don't put in a 1a version, and the 130c is the temperature at which it cuts off and id sticks to that temperature.

if you wanted to get fancy you could use a thermal switch, so once it cools down it would close again and you would not have to take it back apart to replace it.

i happen to have a bag of 130C thermal switches in my parts bin, good for up to 8A at 250V . Id be happy to throw one in an envelope and send it to you if it would be of help.
hard to tell if it would fit

BayouBoy · « **Reply #2 on:** July 15, 2018, 02:42:12 am »

Thanks so much for the info...very helpful, especially for a newbie! In terms of the one you have fitting... the current one I sent a photo of is less than 1/4" square. Not sure what size yours is... the one in there seems to be a pretty tight fit. Let me know your thoughts.. if you think there's a chance of it fitting, that would be very much appreciated if you could send one. Thanks again.l

innkeeper · « **Reply #3 on:** July 15, 2018, 02:52:47 am »

these are longer, I measure them at 1/4" wide by 9/16" long and 1/16th" thick
will it fit

part of the fun of fixing stuff is figuring that stuff out

amyk · « **Reply #4 on:** July 15, 2018, 04:21:28 pm »

Check continuity both of the fuse and the windings.

If the latter are open, you are not going to have an easy time repairing.

BayouBoy · « **Reply #5 on:** July 15, 2018, 04:29:34 pm »

Hi,

I think yours may work.. it's thinner than mine and the thickness may be more of an issue than the length.

innkeeper · « **Reply #6 on:** July 15, 2018, 09:17:18 pm »

send me a private message with your address and i'll put it in the mail tomorrow

james_s · « **Reply #7 on:** July 16, 2018, 01:26:17 am »

I bet you can make it work, it doesn't have to be an exact fit, just make sure it's in good contact with the windings.

For testing purposes you can *temporarily* bypass the thermal fuse to see if the fan runs. It's possible and perhaps even likely that the capacitor failed causing the motor to not spin and that caused the windings to overheat. It's also possible a foreign object jammed it or the thermal fuse may have failed due to a power surge, mechanical damage or vibration.

innkeeper · « **Reply #8 on:** July 16, 2018, 03:52:41 am »

i'll double down on what james_s said as the purpose of a thermal fuse or switch in a motor is to protect it from burning up. so make sure the thermal switches case will conduct the winding heat like the old one would have so it will open if it gets hot.

As James said, you could bypass the fuse to test the motor, and likely its what id do myself to make sure the motor is otherwise functioning. But please don't run it that way permanently as its disabling a safety feature. That feature is there to keep worse things from happening, like potentially a fire or a meltdown.

considering the fuse already went once, you have to ask yourself why it went in the first place, could there be something causing it to overheat that will happen again. If you happened to have an explainable reason, the fan was jammed, then you are probably in good shape.

I also realized none of us actually answered your initial question, how do you know the thermal fuse needs replacing. its a simple resistance reading across the fuse, if its open, its bad, of its low/0 ohms it's good, and don't do that check with it plugged in. also if you bypass it, like James was talking about, the motor would work. that's also a way to confirm its bad.

james_s · « **Reply #9 on:** July 16, 2018, 03:48:39 pm »

I have had thermal fuses fail a couple times without experiencing overheating, and regular fuses fail sometimes without being overloaded. Vibrations, a being knocked over and whacking on the floor, or just normal thermal cycles can cause them to fail the same way solder joints occasionally fail.

BayouBoy · « **Reply #10 on:** July 16, 2018, 05:03:49 pm »

Thanks for the input.. We recently moved so maybe banging around in the moving truck... Not sure about installing the new fuse.. Can I use crimpers to attach new fuse? And do I need to use some type of goop over the new install? There seems to have been some type of laquer covering the winding and old fuse that dried hard.. Since I'm new at this, not sure how important all these details are, but want to do it correctly.

innkeeper · « **Reply #11 on:** July 18, 2018, 08:52:44 pm »

put them in the mailbox today.

BayouBoy · « **Reply #12 on:** July 22, 2018, 08:04:03 pm »

Received your envelope yesterday. Just wanted to thank you for your kindness. Tried attaching using a crimp sleeve.. seemed like a solid connection. Fan still doesn't work.. guess it's time to find an electronics repair place. I learned how to take the fan apart and put it back together though

james_s · « **Reply #13 on:** July 22, 2018, 09:40:44 pm »

If any electronics repair places still exist, they're not going to want to look at a fan. Unless it's a valuable antique there's no way that could be cost effective.

You've come this far, dig in a little deeper and figure out why it isn't working. It's a very simple device and there are plenty of people here to answer questions.

BayouBoy · « **Reply #14 on:** July 22, 2018, 10:08:28 pm »

Thank you for your encouragement. I generally stick with a problem til I find a solution...hate not having closure! I will take it apart again and take a photo of what I've done and post it here. I guess I was reluctant to ask for help, being such a novice, from the more knowledgeable experts on this forum. What I suppose I could try next would be to wire nut the 2 wires coming from fan and see if motor works..that will determine if it is in fact the fuse, correct?.. If it confirms it's the fuse, then my connection is probably faulty.

BayouBoy · « **Reply #15 on:** July 22, 2018, 10:22:34 pm »

Here's what I've done thusfar.

james_s · « **Reply #16 on:** July 23, 2018, 01:30:42 am »

That looks reasonable at a glance. Do you have a multimeter? Do you get any continuity between the AC plug prongs? Does the switch work? Does anything at all happen when power is applied? Did you check the thermal switch to make sure it's normally closed and not normally open?

quinones · « **Reply #17 on:** July 23, 2018, 09:02:00 am »

Check continuity both of the fuse and the windings.

If the latter are open, you are not going to have an easy time repairing.

innkeeper · « **Reply #18 on:** July 23, 2018, 04:01:47 pm »

Quote from: BayouBoy on July 22, 2018, 08:04:03 pm

Received your envelope yesterday. Just wanted to thank you for your kindness. Tried attaching using a crimp sleeve.. seemed like a solid connection. Fan still doesn't work.. guess it's time to find an electronics repair place. I learned how to take the fan apart and put it back together though

no problem at all. I am glad someone's getting use out of them. I will likely never use up this bag of them myself.

your crimp job looks ok though I am assuming you stripped off the insulation on the white wires and crimped it on the wire and not on the insulation.

I would do what the others are saying, do a continuity test. you will need an ohm meter for that, or, one of those cheap continuity checkers with the light bulb in it.
sometimes the wire used for the motor has the enamel insulation on it, and if you happened to crimp on that, it won't conduct. that's just a thing to be aware of.
if you don't own a meter, any cheap ohm meter will do for this purpose, even those cheap harbor freight ones you get for free with a coupon with any purchase.

If you don't know how to do a continuity test, let us know, and we will walk you through it. Just don't do it when its plugged in ok

BayouBoy · « **Reply #19 on:** July 23, 2018, 04:25:38 pm »

Thank you.. I have the multi meter in the photo below, but not sure which setting it should be on. If someone could help with this, I can run those tests that were recommended. Thanks to everyone for the help. The display sometimes has a DC / AC choice depending on where the dial below is set

james_s · « **Reply #20 on:** July 23, 2018, 04:28:43 pm »

You want it on the far clockwise setting, where the Omega symbol is, that will measure resistance.

BayouBoy · « **Reply #21 on:** July 23, 2018, 04:36:33 pm »

OK...when I check the plug prongs it reads 0.L. When I check the fuse connections it beeps, then reads 0.0.

james_s · « **Reply #22 on:** July 23, 2018, 04:42:39 pm »

Sounds reasonable so far. O.L. means out of range, ie open circuit. The beep and 0.0 means short circuit (0 Ohms) which in this case is what you want a good fuse to be. Now you need to find where and why the circuit is open.

BayouBoy · « **Reply #23 on:** July 23, 2018, 04:44:28 pm »

OK.. next step?

innkeeper · « **Reply #24 on:** July 23, 2018, 04:48:54 pm »

was the fan switch in the on or off position when you tested the prongs?


EEVblog Main Site	EEVblog on Youtube	EEVblog on Twitter	EEVblog on Facebook	EEVblog on Odysee

Author Topic: Thermal Fuse for oscillating fan (Read 14506 times)

Share me