Author Topic: How to unfix this fan from the shaft of this DC motor?  (Read 2428 times)

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Offline saalucTopic starter

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Re: How to unfix this fan from the shaft of this DC motor?
« Reply #25 on: December 15, 2024, 10:29:07 am »
better to bend them out with pliers so you can bend them back for reassembly


Apply a bit of "dremeling" on every crimps.

better to bend them out with pliers so you can bend them back for reassembly

It may work on this small motor, with larger ones from impact wrenches or cordless drills I prefer dremeling because it is to hard to bend them.


I bent all of them out, but when I pull the metal cap, it does not come out, it does not move up even a bit. It seems that something else is preventing it from coming out. what is the solution?
Update: I levered the metal cap from beneath, and it could be pulled out.
One of the brushes has been broken in half and has lost contact with the collector.
« Last Edit: December 16, 2024, 12:50:58 pm by saaluc »
 

Offline timeandfrequency

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Re: How to unfix this fan from the shaft of this DC motor?
« Reply #26 on: December 15, 2024, 02:48:37 pm »
[...], can the fan be refixed strongly on the new DC motor's shaft? Or I will need a new fan too?
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 ?
 

Offline Poroit

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Re: How to unfix this fan from the shaft of this DC motor?
« Reply #27 on: December 16, 2024, 06:41:11 am »
I bent all of them out, but when I pull the metal cap, it does not come out, it does not move up even a bit. It seems that something else is preventing it from coming out. what is the solution?
[/quote]

Do I read this correctly?

You have bent out the clips on the bottom of the motor?(attached)

The fan is still attached to the motor shaft at the other end, so you wont be able to pull the guts of the motor out easily if at all.

You will still need to remove the fan to access the motor mounting screws that timeandfrequency pointed out.
 

Offline saalucTopic starter

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Re: How to unfix this fan from the shaft of this DC motor?
« Reply #28 on: December 16, 2024, 12:57:50 pm »
I bent all of them out, but when I pull the metal cap, it does not come out, it does not move up even a bit. It seems that something else is preventing it from coming out. what is the solution?

Do I read this correctly?

You have bent out the clips on the bottom of the motor?(attached)

The fan is still attached to the motor shaft at the other end, so you wont be able to pull the guts of the motor out easily if at all.

You will still need to remove the fan to access the motor mounting screws that timeandfrequency pointed out.
[/quote]

I did not want to pull out the "guts" of the motor, but I wanted to remove only the "cap". As I updated the previous post, I have now removed it. One of the brushes is broken and has no contact with the collector.
 
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Offline saalucTopic starter

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Re: How to unfix this fan from the shaft of this DC motor?
« Reply #29 on: December 18, 2024, 04:35:56 pm »
[...], can the fan be refixed strongly on the new DC motor's shaft? Or I will need a new fan too?
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 ?

The fan assembly is for a haidryer. There is no new one to buy.
 

Offline Gyro

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Re: How to unfix this fan from the shaft of this DC motor?
« Reply #30 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:
« Last Edit: December 18, 2024, 08:32:13 pm by Gyro »
Best Regards, Chris
 
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Offline saalucTopic starter

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Re: How to unfix this fan from the shaft of this DC motor?
« Reply #31 on: December 19, 2024, 11:25:17 am »
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:


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.
2465449-0

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
 

Online CatalinaWOW

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Re: How to unfix this fan from the shaft of this DC motor?
« Reply #32 on: December 19, 2024, 11:50:45 am »
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.
 

Offline timeandfrequency

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Re: How to unfix this fan from the shaft of this DC motor?
« Reply #33 on: December 19, 2024, 07:25:57 pm »
Might your method break some parts?
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.


[...], can the fan be refixed strongly on the new DC motor's shaft? Or I will need a new fan too?
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 ?

The fan assembly is for a haidryer. There is no new one to buy.
Well, the price of a new hair dryer is around 20 bucks. Not sure if it's worth to mend it.
« Last Edit: December 20, 2024, 08:19:52 pm by timeandfrequency »
 
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Offline Gyro

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Re: How to unfix this fan from the shaft of this DC motor?
« Reply #34 on: December 19, 2024, 08:10:53 pm »
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

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.
« Last Edit: December 19, 2024, 08:13:18 pm by Gyro »
Best Regards, Chris
 
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Offline saalucTopic starter

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Re: How to unfix this fan from the shaft of this DC motor?
« Reply #35 on: December 25, 2024, 12:48:07 pm »
Might your method break some parts?
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.


[...], can the fan be refixed strongly on the new DC motor's shaft? Or I will need a new fan too?
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 ?

The fan assembly is for a haidryer. There is no new one to buy.
Well, the price of a new hair dryer is around 20 bucks. Not sure if it's worth to mend it.

Thank you very much indeed for your detailed tutorial.
 


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