Dummies guide to...

[HeliIntervention]

Originally Posted by ZuvieleTeile

Franky, I would forget it . . .
Too much hassle and you would need at least two magnifying glasses in series . . .

After buying 3 of them I had shelled out a $100. I decided hook or by crook I'm rewiring one. After several attempts and testing each phase I managed to rewire 2 stators it took sometime taking breaks between phases. The broken ones I saved for parts.

Thanks for your contribution to this thread. It has helped me understand how these things work. Now when I want to upgrade my 450 I'll have some idea what to do.

Sent from Mars. Using Mars Rover.

[Todd Moriarty]

The best bit of advice I have been given was from ZT, and this was it:

http://i.caendle.de/dev/test2/

[HeliIntervention]

Originally Posted by l4rg0

The best bit of advice I have been given was from ZT, and this was it:

http://i.caendle.de/dev/test2/

Is there a english version and what is the purpose of this tool?

[Todd Moriarty]

Click EN at the top, and it is in english. It is a calculator for winding patterns. It will output something similar to this:

[LogoFreak]

Originally Posted by l4rg0

The best bit of advice I have been given was from ZT, and this was it:

http://i.caendle.de/dev/test2/

This link really helped me understand the concept, thanks!

Now I have a question. How do you calculate what the new windings limits are? Max amps, max watts, etc...

[LogoFreak]

If I want to keep the same kv after rewinding the motor should I be counting the amount of turns per pole while unwinding the original windings?

[Laurens]

Definatly yes, and keep in mind you have to use the same termination, otherwise you can start calculating the new amount of turns again;-)

[LogoFreak]

Ok, but if I wanted to use a higher gauge wire I won't be able to fit the same amount of turns.

[Laurens]

You will most of the time if you're replacing a multistrand wire.

[ZuvieleTeile]

The start for any rewind calculation is always the amount of space I have on a stator.
Secondly the number of turns I need for my target Kv.
And thirdly, which wire size you can fit into the available space with the amount of turns I have determined.
I bigger helis you have more choices by changing the Kv and Pinion to get to your target head speed.

[LogoFreak]

Originally Posted by Laurens

You will most of the time if you're replacing a multistrand wire.

That makes sense. What about my previous question on calculating the limitations of the the wind? Amp/watt rating.

[LogoFreak]

Originally Posted by ZuvieleTeile

Secondly the number of turns I need for my target Kv.

How do you calculate that?

[ZuvieleTeile]

Originally Posted by LogoFreak

How do you calculate that?

Not a serious question, right?

[LogoFreak]

Originally Posted by ZuvieleTeile

Not a serious question, right?

Am I missing something? As far as I know a specific formula for figuring out how many turns you need for a given kv has been given yet.

[ZuvieleTeile]

Originally Posted by LogoFreak

Am I missing something? As far as I know a specific formula for figuring out how many turns you need for a given kv has been given yet.

There is no formula for a specific number of turns for a specific Kv.
As mentioned above there are two different methods.
Calculation windings for the same motor from a previous known Kv, or doing a test wind.

If there would be a formula then it would have to include stator height, magnet strength, number of poles, bell flux ring thickness, stator sheets cut, relativity of the stator's stem to hammer head etc. etc.
Lots of variables.
If you would like to, you could comb through the HF motor forum, collect all the available data, ask the forum members to submit more data and put it all into a spread sheet, so that we can narrow it down to a "formula" of some kind.
Still, it would not be all inconclusive.

Easiest is always a test wind with thin wire and, in case of a YY termination, just half a motor.

[Todd Moriarty]

I know it seems like we are trying to be difficult, but there really are that many (Plus many more when you take ESC variables into account) variables involved. Like ZT mentioned, your best bet is to go through this forum looking for the specific motor you want to rewind, and see what data you can find. In the case of the 4035 I am working on, I can use the experience of others to build off of, but in the case of the 420H I am rewinding, I had to count the turns as I removed them, and will have to build my own knowledge base off of that.

Again, we really aren't trying to be difficult, it really is that complicated. the winding itself is the easy part!

[LogoFreak]

Originally Posted by l4rg0

I know it seems like we are trying to be difficult, but there really are that many (Plus many more when you take ESC variables into account) variables involved. Like ZT mentioned, your best bet is to go through this forum looking for the specific motor you want to rewind, and see what data you can find. In the case of the 4035 I am working on, I can use the experience of others to build off of, but in the case of the 420H I am rewinding, I had to count the turns as I removed them, and will have to build my own knowledge base off of that.

Again, we really aren't trying to be difficult, it really is that complicated. the winding itself is the easy part!

Fair enough, I just kept thinking that there had to be a very scientific exact way of calculating it. After all motor manufacturers can't be "winging" it. I though maybe there was an "app" out there like CC or the above suggested that gives you winding patterns.

New question. When removing the old winding some of the motors I have are coated in a epoxy resin (I think). How are you guys removing this?

[Todd Moriarty]

Originally Posted by LogoFreak

Fair enough, I just kept thinking that there had to be a very scientific exact way of calculating it. After all motor manufacturers can't be "winging" it. I though maybe there was an "app" out there like CC or the above suggested that gives you winding patterns.

New question. When removing the old winding some of the motors I have are coated in a epoxy resin (I think). How are you guys removing this?

The only really badly epoxied motor I have run across in my limited experience has been my 4035. Luckily, that motor has been extensively covered in this forum, so I just cut and yanked. After removing the wire and paper, it still took me almost an hour to file out the epoxy from the slots.

As far as an app, I am sure most of the major motor makers have modeling software, but something like that would be prohibitively expensive at the hobby level. Luckily we have a fair amount of knowledge accumulated here to draw from.

[HeliFX]

your not designing a motor your rewinding one for better performance and before you say "why don't the manufacture just not do what where doing now"
1. there automated machine winding system can handle the larger O.D. copper
2. Delta is usually wound with one continuous wire length. limited the number of machine load and setup.
3. using thin o.d copper in bundles is just easier to work with.

nothing is more accurate then using a thin wire and running the motor to determine your target Kv. Those are hard facts.
If reverse engineering is too difficult via counting wire turns and using the countless forums here showing how to calculate then do the wire test and check.

Complex formula's can never factor in every conceivable variable. It not 1 + 1 =2
manufacture use CAD base systems which can simulate real-world scenario based on user input. Besides there not re-inventing the wheel they copy each other and tweak the design to there own specs and findings.

Most who have venture into world rewinding have put a certain amount of effort to gather information and decipher it.

Before I started this forum was not even available.
Try translating German to English now that a lot fun

Originally Posted by LogoFreak

Fair enough, I just kept thinking that there had to be a very scientific exact way of calculating it. After all motor manufacturers can't be "winging" it. I though maybe there was an "app" out there like CC or the above suggested that gives you winding patterns.

New question. When removing the old winding some of the motors I have are coated in a epoxy resin (I think). How are you guys removing this?

[Mercuriell]

There's some good advice here - in a high level forum such as this with world experts it's easy to forget the problems with basic concepts - I found ZT's (and others) comments on kV particularly illuminating as I too thought there must be some formula for working it out from the major variables! I thought it worthwhile stickying this so others may avoid the ire of some of our more senior contributors - don't forget the learning part of the Helifreak ethos !!!