Electronics > Repair
How to unfix this fan from the shaft of this DC motor?
Gyro:
I thought the idea, after removing the motor end cap, was to replace it, or just the brushes, to repair the existing motor without removing the fan. Otherwise there was no point in removing it.
Just an example listing (I don't know the motor size but they come in standard sizes)... https://www.ebay.com/itm/285731848223
Edit:
saaluc:
--- Quote from: Gyro on December 18, 2024, 07:18:32 pm ---I thought the idea, after removing the motor end cap, was to replace it, or just the brushes, to repair the existing motor without removing the fan. Otherwise there was no point in removing it.
Just an example listing (I don't know the motor size but they come in standard sizes)... https://www.ebay.com/itm/285731848223
Edit:
--- End quote ---
Dear Chris
Thank you for your insights.
Best Option in terms of cheapness, is repairing the brushes of the existing cap (attached picture). Of course, repairing the broken arm is not easy.
Second best option is replacing the entire cap.
(Size and type of the cap: https://www.aliexpress.us/item/3256805967346108.html?gatewayAdapt=glo2usa4itemAdapt
Size and type of the motor: https://www.alibaba.com/product-detail/Model-390-395-Dc-Motor-Shaft_1600088767935.html)
Yours
saaluc
CatalinaWOW:
An economical, but uncertain path to a cheap repair is to check second hand stores for a serviceable replacement, either the whole hair dryer, or salvage the motor from a similar model
On a job I once did we had a need for a large number of hair dryers and this turned out to be a good source.
timeandfrequency:
--- Quote from: saaluc on December 13, 2024, 04:45:56 am ---Might your method break some parts?
--- End quote ---
I used this method 3 or 4 times a few years ago and if you follow my instructions and those of @drhex who reformulated it in a better english than mine, and also use the tools I suggested, you won't break any part.
A few cracs in the fan blades where the string was placed may appear. Remember that such a fan assembly is clearly constructed in such a way that it cannot be disassembled. So it's not really realistic to expect every piece to remain in perfect condition.
It is wise to use only one unique strong string. You should put only one loop of this string around each fan blade. It is important that the pulling force is the same on each blade : you will see that the string loops will slightly slide around the screwdriver's blade (used as a lever) to provide an uniform pulling force. The more the string is slippery, the better is goes : you may use a bit of liquid soap for that.
The force required is really measured in tens of kg (hundreds of N for purists).
You can help by warming up the motor shaft through the existing hole in the hub of the fan rotor. Use the tip of your soldering iron, but not more than 20 seconds. If the plastic around the shaft completely melts, the fan rotor will be destoyed.
I couldn't find a similar fan in my stash, so I used a more vanilla one.
Here are some photos showing how to use the vice to hold the assembly, and the screwdriver as a lever.
You must use a vice much larger than mine: jaws must be at least 180 mm wide, otherwise there is not enough room to place the fan assembly under the jaws.
Avoid tightening the jaws against the plastic frame: the fan assembly must remain loose under the jaws.
--- Quote from: saaluc on December 18, 2024, 04:35:56 pm ---
--- Quote from: timeandfrequency on December 15, 2024, 02:48:37 pm ---
--- Quote from: saaluc on December 14, 2024, 03:25:56 pm ---[...], can the fan be refixed strongly on the new DC motor's shaft? Or I will need a new fan too?
--- End quote ---
Yes you can refix the existing fan rotor on the new motor's shaft. It's a press fit.
If there's a brass sleeve on the existing shaft, it will need additional work, but it is still possible.
Tell us a bit more about that fan assembly.
Where does it come from ? What it is used for ? How much would it cost to buy a new one ?
--- End quote ---
The fan assembly is for a haidryer. There is no new one to buy.
--- End quote ---
Well, the price of a new hair dryer is around 20 bucks. Not sure if it's worth to mend it.
Gyro:
--- Quote from: saaluc on December 19, 2024, 11:25:17 am ---Dear Chris
Thank you for your insights.
Best Option in terms of cheapness, is repairing the brushes of the existing cap (attached picture). Of course, repairing the broken arm is not easy.
(Attachment Link)
Second best option is replacing the entire cap.
(Size and type of the cap: https://www.aliexpress.us/item/3256805967346108.html?gatewayAdapt=glo2usa4itemAdapt
Size and type of the motor: https://www.alibaba.com/product-detail/Model-390-395-Dc-Motor-Shaft_1600088767935.html)
Yours
saaluc
--- End quote ---
Ouch, those brushes wore down to the point that one was 'grabbed' and dragged round to the opposite side of the commutator (you can see that it was on the verge of happening on the remaining brush), hence the sudden open circuit.
If you decide to go that way, I would chose the entire cap replacement, I don't see a broken arm repair lasting.
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