Triple Rewind of Unite 500W Motor

[safe]

Hoping For Success

I suspect that for AussieJester there was that moment (which we've all experienced) where he looked at the windings and realized:

"Oh no... I really did spiral wind this stupid thing."

...my guess is that he will more patiently go back and do an excellent job this time and rewind the motor again the right way. He will then test it and if it's awesome (which it should be) he will let us know.

The math suggests that he should get AT LEAST two horsepower out of such a motor because I already did that for 500 miles on mine. With his crazy high 100 amp controller and this current hungry rewind the math suggests he should be up over four horsepower with this motor at peak.

So we wait... :daisy:

 

[AussieJester]

I suspect that for AussieJester there was that moment (which we've all experienced) where he looked at the windings and realized:

"Oh no... I really did spiral wind this stupid thing."
:

Quite the contrary i like many before me have given up trying to get through your one track closed mind. I told you twice you were incorrect with your little photochop both times you refused to accept this why bother repeating it a thrid **** took me 3 attmepts to get you to realise i was using AWG20 wire for the rewind...Suffice to say i have since stripped the windings and it happened to come off surprisingliy well and LOW AND BEHOLD you were WRONG....

 

[safe]

No closeup huh?

Hmmmm.... well... hopefully you get it right this next time.

Just remember... start in the SAME groove with each wind.

Here's a tip:

In order to be sure to get the right starting points I used a piece of masking tape on the iron core and on the commutator and marked them with a pencil. That way I didn't have to rely on visual cues to figure it out.

It should go like:

Position One Commutator - Layer One Winding - Position One Core
Position One Commutator - Layer Two Winding - Position One Core

Position Two Commutator - Layer One Winding - Position Two Core
Position Two Commutator - Layer Two Winding - Position Two Core

Position Three Commutator - Layer One Winding - Position Three Core
Position Three Commutator - Layer Two Winding - Position Three Core

etc...

 

[AussieJester]

hopefully you get it right this next time.
.

Hopefully you will start to read others posts and comprehend them too...instead of going on and on and on like a broken record.

EDIT. P.S for the god knows how many time..i dont have a 100amp controller aaaaaaaaaaagh its less painfull beating a head against a wall than trying to communicate with you safe honestly.

 

[safe]

The picture betrays you AussieJester... it clearly showed that the windings were spiral wound.

Maybe with this next one things go better.

Hey it's really no big deal for me... I'm trying to help you... on my end things have worked great. My hope was to "share the wealth" so to speak and help you upgrade your condition.

The math isn't going to change just because things didn't work well in your case.

 

[AussieJester]

Do you ever shut up?

 

[safe]

Moving On...

Issues with AussieJester aside.

I still have to decide on which rewind I'm going to do for this next one.

My current options are:

11x2=22 Kind of under reving if I'm in 24 volt mode which has the better range, but the 48 volt mode is great. This is the one that I managed to break 60 mph with. (on a downhill) This is also the rewind I used in the YouTube video. (it was used for about 500 miles)

10x2=20 A good motor for 24 volts because one less turn means a little more rpms and a little less resistance. This might be a nice middle performance motor, but there's no way to run it at 48 volts, so that's somewhat limiting.

7x3=21 I thought about this one first because it's resistance is really low and at 24 volts I'm maxing out the no load speed (5000 or so) which means that it's a very good choice for a dedicated 24 volt machine. This is also not going to work for 48 volts.

...sometimes I just flip through the three rewind options and can't decide on which one to go with. I still kind of am leaning towards the 7x3=21 just because it's a true "Triple" and it would be the most extreme rewind I've ever done. But as far as maximum power while using 48 volts (on my gearing) the 11x2=22 is still probably the best for that, however, the range is not so good when you use that much power. (and when I remove the NiCads the range is going to drop to just a couple of miles which is just silly)

It would have been better if I ordered some other thickness of wire than 20 AWG. There are just only so many ways that you can do a single thickness. Had I stocked up on some other gauges then I would have more options.

Rewinding is becoming a hobby in itself.

I've been working on my Project #003 bike lately, so until I get at a point where I want to stop on that one these rewinds are on hold.

 

[safe]

Numbers of Winds vs Current Flow

One can ask the question:

"Can't I increase the current flow (with the byproduct of increased no load speed) by simply using a thicker wire... isn't all this multiple wind stuff non-sense?"

Well... yes and no...

Increasing the thickness of the wire reduces the number of turns possible and at some point it becomes harder to get the thicker wire to pack well in the iron core during the winding process. So while in principle it's possible to use really, really thick wire to wind your motor the rate of increase of the current that can flow through the motor increases much faster if you switch to multiple windings.

The "bottom line" is that it's just easier to get to the higher current (lowered resistance) by using multiple winds.

However, the drawback is that more turns and winds to deal with means a longer and slower winding process, so that's negative on the multiple winding side. Also, there are more ways to make mistakes.

Generally speaking a Double or Triple would be as extreme as one might ever want to go. And one needs to remember that you can achieve the same performance improvement with a larger, higher voltage battery.

But in our demonstration case of the 500 Watt Unite motor we face this basic fact... in order to attain the ideal performance out of this motor that is designed to run at 36 volts and about 3000 rpm we would need to increase the voltage to 72 volts and that would give us a no load speed of 6000 rpm which we know from past experience is the upper bound for this type of motor. To get to 72 volts you would need to:

Double the size of the battery. ($$$)

Buy a new 72 volt controller since your stock controller will not work. ($$$)

...but if you instead did a simple Single-to-Double Rewind with the same wire thickness then you get the same (doubled) no load speed and can keep your existing controller because the rewound motor will now just run more efficiently than before. Either way you get a motor that spins up to a higher no load speed, so you have to deal with that no matter what you do.

Anyway... that's the concept... here's a chart that shows how the "Number of Winds" is related to the current flow. More winds get you more current.

 

[duivendyk]

Multiple parallel windings can be useful to achieve a better armature fill factor (larger copper crosssection,lower resistance,lower loss) esp if larger conductor sizes are involved,this will most likely be the case for lower voltage higher power motors,for instance 500W, 12V. So if you want to get the best performance it can sometimes be beneficial,but does involve a lot of rather tedious, painstaking work.

 

[safe]

I think you start with your needs as far as gearing, battery voltage, controller, etc.. and then work backwards from there to get an idea of the rpm/volt value you want based on getting under the maxamum no load speed. From that you know the number of turns you need. Then you consider the maximum thickness that is practical to wind with. (20 AWG is good, but 19 AWG or 18 AWG might still be workable too) You then see if everything is going to fit based on the cross sectional area.

If you are lucky you can get the per wind turn count you desire and be able to squeeze in a Double or even a Triple with a fairly thick wire.

But it's all a very vague process of how to decide...

I'm still fluctuating back and forth on my options. The 7x3=21 option is at present sticking out as my "favorite of the moment". It would be nice to cap this thread off with a true "Triple Wind" thus giving the thread a nice conclusion. :crowngrin: