Combustion Fan Malfunction

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The Doktor
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Tue Jul 17, 2007 12:00 pm

Gah, I build my combustion with the standard 80mm computer fan. After only a handful of shots working beautifully, the fan just stopped working. When I hit the switch controlling the fan, it actually just locks up. It spins free when theres no juice to it, but when I turn it on, the blades just get stiff and dont want to turn. When you try to spin the blades with the juice on, it feels like theres a magnetic force stopping the blades from spinning in either direction.

The battery IS connected to the right wires and everything should be working. The problem comes into play where I really dont feel like cutting my combustion chamber to replace the entire fan.

Any suggestions? Has anyone ever had this happen to them?
Spedy
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Tue Jul 17, 2007 12:14 pm

Thats quite interesting...... Probably a short-circuit inside the fan. A replacement is needed. You could fire it a bunch of times in quick order and pull the fan out before it cools and gets hard again. If you have a suitable heat source, you could soften the fan's frame until you can pull it out. Thats all I got.
The Doktor
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Tue Jul 17, 2007 12:29 pm

Ya, getting the old fan out isnt any problem... Its the whole getting a new fan in thats going to be the problem... I shoulda taken a good look at the fan before I put it in... Is there any chance I can pull off the blades and/or the motor and leave the frame inside the chamber so I can put a new blade and motor assembly back into the original frame? I havent dealt with computer fans too much.
Spedy
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Tue Jul 17, 2007 12:39 pm

That probably depends on the fan. You may/may not be able to. Good luck with the cannon. :)
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potatoflinger
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Tue Jul 17, 2007 1:15 pm

If it is a short circuit, you could take the fan and motor off and leave the frame, then buy a new fan (the same type) and take the motor and fan off of the new one and install it in the old frame, but if it isn't a short circuit, you will probably have to buy a whole new fan and frame.
locksmith
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Tue Jul 17, 2007 3:05 pm

dremel tool and cut it out
Thrilla
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Thu Jul 19, 2007 12:08 am

The electronic driver is broken.

How brushless fan works without spark is because of its driver.
Image

The blade piece has a ring of magnet inside, it doesn't do the turning. So replacing the blade will not work.


The bottom part, shown in pic above, has many bits to the driver, each bit power on in a set sequence, thus pushing the blade electro-magnetically.


How many volts did you feed the fan? Over 13v will usually harm the circuitry inside.
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