Author Topic: Hub motor from scratch?  (Read 431 times)

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Offline electromateria

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Hub motor from scratch?
« on: July 14, 2021, 04:45:55 am »
Is there any good DIY that really explains how to do the windings? Ideally without overdoing it with the technical jargon, I need something very basic but thorough.

I'm not trying to build a professional grade hub motor, just something that (at least kind of) works.


« Last Edit: July 14, 2021, 04:58:39 am by electromateria »
 

Offline strawberry

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Offline electromateria

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Re: Hub motor from scratch?
« Reply #2 on: July 14, 2021, 06:21:21 am »
^Tyvm! Can you help me understand a few things please?

How does wire thickness affect the output?

How does coil count affect the output?

How does the number of phases affect the output?
« Last Edit: July 14, 2021, 06:24:57 am by electromateria »
 

Offline strawberry

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Re: Hub motor from scratch?
« Reply #3 on: July 14, 2021, 08:36:12 am »
efficiency and output power (copper and/or steel mass vs applied load) eddy currents.. ohms law..

winding can be made 240V 1A or 24V 10A

speed vs torque
https://things-in-motion.blogspot.com/2019/01/selecting-best-pole-and-slot.html
 

Online Gyro

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Re: Hub motor from scratch?
« Reply #4 on: July 14, 2021, 08:38:55 am »
The hub motor that strawberry shows is a brushless design which requires an external ESC to provide the necessary drive (electronic commutation). It is quite an engineering challenge to build (all laminated core) unless you are re-winding an existing one.

Looking at the brushed DC motor that you have in your other thread (you seem to have a lot of those now - it's getting difficult for people to understand them all in context!) I would assume that it contains an epicyclic gearbox to achieve the necessary speed reduction and torque transformation from motor to outer wheel. Again, a bit of a challenge.


Edit: I didn't realise you could get BLDC motor stators on Ali. Thinking about it, I suppose they're just spares for LG washing machines etc.
« Last Edit: July 14, 2021, 10:19:47 am by Gyro »
Regards, Chris

"Victor Meldrew, the Crimson Avenger!"
 

Offline strawberry

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Re: Hub motor from scratch?
« Reply #5 on: July 14, 2021, 04:53:32 pm »
Edit: I didn't realise you could get BLDC motor stators on Ali. Thinking about it, I suppose they're just spares for LG washing machines etc.
can ask factory what they have in stock and if they could sell sample
sadly there is not much in India like this

higher chance to restore BLDC than brushed motor ,due to brush and commutator wear and then you have gears(if you have workshop then it is possible to restore/replace commutator)

to test for degraded insulation need high voltage megohmmeter or insulation tester and inductance or milliohm meter to test shorts in phase windings
 

Offline Old Printer

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Re: Hub motor from scratch?
« Reply #6 on: July 14, 2021, 05:42:18 pm »
Look up a model airplane forum like rcgroups and lookup the motor section. They are very into building and rewinding brush-less motors. There will be a lot of info on modifying wire gauge, # of turns and different pattern winds. Also a lot of battery and electronic speed control diy projects.
 
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Offline electromateria

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Re: Hub motor from scratch?
« Reply #7 on: July 16, 2021, 04:11:55 am »
The hub motor that strawberry shows is a brushless design which requires an external ESC to provide the necessary drive (electronic commutation). It is quite an engineering challenge to build (all laminated core) unless you are re-winding an existing one.

Looking at the brushed DC motor that you have in your other thread (you seem to have a lot of those now - it's getting difficult for people to understand them all in context!) I would assume that it contains an epicyclic gearbox to achieve the necessary speed reduction and torque transformation from motor to outer wheel. Again, a bit of a challenge.

I want to build my own stator from highly accessible and cheap parts (bolts, brake rotor, etc).

If I build a mid size motor and use extremely overpowered, extra-large magnets what would happen? I have around 10x 1"x0.25" circular neodymium magnets - if I buy 10 more would that be enough to build a crazy powerful motor?

Direct drive hub motors are the old style and don't have the planetary gearbox, it's less torque but still very functional. Was watching this video last night, some boring parts but over all very solid:




.




I have a 3d printer (been procrastinating fixing it for around 2 months now)... nlyon plastic gears should work for building a planetary. I already have the CAD files for lots of planetary gearsets. Just want to keep things super simple though, so direct drive.
 

Online Zero999

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Re: Hub motor from scratch?
« Reply #8 on: July 16, 2021, 09:57:05 am »
This is more of a mechanical, than electronics problem.

It's extremely difficult to do. How are you going to secure the magnets, so they don't stick to the stator?

A very tight clearance between the coils and the magnets is required to achieve good efficiency.

Nylon is fine for cogs which aren't subject to much torque, but no good for high torque applications. Quite often nylon is used for the gears nearest to the motor and steel, at the load side.
 


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