Stir plate build: need help

I have this old fan that was used to cool aquarium lights years ago. It works when I direct wire it but if I use a power supply type plug it does not. What am I missing. I tried two different plugs.

 

is it an A/C, or D/C fan?

Most of the power supplies from cell phone chargers etc, are 5-6V, and more than likely will not work with an A/C type fan, you will need to wire it ti a dimmer type switch.

 

I am fairly certain it's an AC fan. So I bought a toggle switch and a rheostat. Can I make this work with a standard power cord plug?

 

if it is a 120v fan, then it would be best to use a dimmer switch if it is a 12v fan then your rheostat will work with a 5-12v power source.

It all depends on what you have exactly.

 

If it's a 12v DC fan and you hook it up to 110v AC, it will soon be a dead 12V DC fan motor. It should indicate somewhere on it what the voltage requirements are. If not, hook it up to a 12v source FIRST and see if it will spin. Use your car battery if need be.

 

Its a 120v AC Fan and the dimmer worked just fine. Now I just need a more powerful magnet. Radio Shack magnets are not strong enough

 

!f you have an old hard drive lying around, the magnets in them are very strong.

 

I am starting my build this weekend (or maybe tomorrow, if I get to stay home from work due to the impending snow here). I actually skipped the hard drive magnet route and picked up some nice strong magnets online.

Specifically, I am going with the Magcraft NSN0582. They have a pull force of 16 lb. each, and are small enough to easily mount. I am going to mount two of them in a "puck" arrangement, and mount the puck with Velcro so that I can reposition or change it out, if needed.

The idea for mounting is from Catt22 in respsonse to my question about how to mount them in this thread.

 

I use 3M 77 Spray adhesive to attach the "puck" to the face of the fan. The adhesive sets relatively slowly and this allows you to move the "puck" to get it properly centered, yet it has enough strength to hold it in place. Once I am satisfied with the centering, I put three our four drops of Super Glue down the center hole to secure the disc more permanently. You can still separate the disc from the fan motor if necessary. The Velcro will probably work, but I think you may find it difficult to get the disc well centered and it's important to get this right.

 

Thank you for the tip, again. I always fear mechanical failure and want to make sure I can remove the puck if the fan dies, based on how many times I've had to replace them in a PC. I do have my puck "done", by the way - thanks to you! Just no center hole as of yet. We had some 3" round 1/8" birch circles from some craft project gone by that I laminated and drilled out. Laminated two sets of two, to provide 1/4" on each, drilled out the holes for the magnets on one after making a quick template for it, then laminated the two halves together.I have center marked, and just need to throw it in the drill press then.

 

5 minute epoxy is also a great solution. ives you about 5 minutes to center it up.

 

The problem I have with using epoxy is that it can be very tough to take it apart if necessary later on for any reason.

 

True, but I highly doubt, at least in my case, that I will ever need to replace my fan. If I do, it will be high time to upgrade my stirplate to one with better control, and maybe some heat.

However, you are right, epoxy is permanent.

 

I used a hot glue gun to attach the puck to the fan. It doesn't give you as much time to position, but it's easy enough to redo if you have to.

 

+1 on hot glue.

 

True enough. I just built mine last week and all ready had to replace the fan. Found out the hard way that case fans have either sleeve or ball bearings. The sleeve bearings are only made to be mounted horizontally and puked on me almost immediately. I ripped through my pile of old CPUs until I found a fan that had ball bearings (Run the model number through Google to find it's specs) and it has held up to initial testing. FYI, the epoxy is pretty easy to break loose from the fan. However, I did have to take my "puck" to the wire wheel before adhering it to the new fan.