Arlo has another build ;) 06 BWS 50 (zuma) Hybrid! IT RUNS!

Arlo1

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Ok so yes I know I have to many builds but..... Well my GF wants her scooter faster so... I priced out big bore kits and up-gear kits ect and that would be ok but I know I can help convert her to electric if its reliable and user friendly enough.
What I found is I have a spare outer clutch bell from the back clutch and I found a brake hub off some china atv we were chucking out. Then I found a 3 phase stator from the pile of stators at work the plan is to rewind it and cut off the extra metal thats not needed.
The plan is for electric assist :)

My questions are...
#1 How many magets do I want to glue in the rotor?
#2 What batterys would be best (perferably something that doesnt require a bms... What was it zero bike uses? I think luke said they self ballance
#3 How many amps can a 6 fet controler produce? (stung out but reliably)
#4 What would the max hp I can expect from this motor? I bet ~10hp because it can rev hi because its on a gear reduced section of the drivetrain so ~75kv will be what I wind to I just need to figure out the gear ratio we will use.

The main goal is a higher top speed but I know this scooter will have a LOT of potential and the only thing that wont be a breeze for me is mounting the stator because I have to machine the clutch cover to fit this inside and weld or bolt on a new section!
 

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Some more pics
Oh and the magnets are N42 I have to mesure them again.
 

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I think the magnet polls have to be a multiple of two but thats all I remember. And the stator teath have to be a multiple of 3....
 
Does anyone know the max E-rpm of the crystalyte controllers we use?
I need to select a number of magnet polls that keeps the controllers with in the electric rpm it can handle.
I will look at work today but I think the up gear kit is 15-50 so 3.33 gear ratio so the electric motor will spin 3.33 times for a wheel rpm and the wheel Dia is 19.5 inches so the wheel will spin 1035 rpm at 62 mph (100km/h) A kinda goal cruise speed.
And that means the electric motor will spin 3446 rpm. So I think a hi magnet count is not going to be a problem.
But if someone can tell me what max e-rpm our controllers are that would be great, I will be using a 12 fet and preferably with variable regen.
 
Thanks marko.
And damit
I think I need to build a new magnet ring :cry: mine is to short.....
 
Hey arlo itanliano
is that glue for magnets is something tested before with mags?
infineon was 5 or 6k rpm max ( dont know what e-rpm means)
 
whatever said:
Hey arlo itanliano
is that glue for magnets is something tested before with mags?
infineon was 5 or 6k rpm max ( dont know what e-rpm means)
5 or 6 k is the rpm of the motor but the E-rpm is what matters and E-rpm is based on the magnet polls meaning the controler has to switch fets on for every magnet poll that comes by that phase!
 
ERPM is just RPM * Magnet Pole Pairs.

So with a with a 20 pole motor at 6000 RPM
ERPM = 6000*10 = 60 000.

To turn it into a number that means something to the real world, divide it by 60 to get Motor Electrical Frequency in Hz
60,000 ERPM = 1kHz

If you have an electrical frequency of 1kHz, and you want to have any chance of controlling it, you will need PWM of around 12kHz, and a current control loop running at least at 600Hz, 1kHz would probably be better. You want to have at least 10 cycles of PWM per motor electrical cycle, and you want at least 1 current control loop cycle per 2 motor electrical cycles. The more current control loop cycles per electrical cycle the better your control is going to be. I am not a motor controller designer, so I could be wrong on that current control loop rule of thumb rate.

-ryan
 
I just took another scooter apart Im big boring and found the tranny is ~ 14.7:1 stock and with an upgear kit it will be 11:1-12.22:1 so the electric motor rpm will be a lot higher! More Around 1035*12.22 = 12647 :shock: I might have to concider a different option! Like my small collossus!
 
At 120 000 E-rpm my motor is good for 15000 rpm with 16 magnet polls so that would work but Im a little concerned with a peice of metal spining that fast!
 
So with a little more digging and reserch I think the 18 tooth 16 magent poll will be perfact! I just need to be carefull to make sure its safe!
Here is a picture from a link biff give me!
 
So I have the basic idea of what Im going to do but I cant find a peice of cheep steal for making my magnet ring.... This was started to be a quick and cheep project.
Oh well I will win I always do.
 
OK So. I am almost done machiening the magnet bell... I got my new clutch bell today and welded the new peice of pipe to it. And Machined it all.
My Air gap is .021" Or .5mm I will Have .046" or 1.1mm gap between each set of two magnets. (2 will be + followed by gap then 2 -) 16 sets for 32 magnets total with 94% coverage! They are N42 neo mags I ordered a while back and it just turns out biff said n42 is better because they take more heat!
I am making it as light as possible. The magent ring is .076" or 1.93mm Thick I am not sure how thick it should be???? I want it light but Its going to rev ~14000 rpm!

And I am going to ask biff to look if I should cut the ends off the stator lams that are perpendicular to the magents.
 

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Bump for anyone who know if the stator lams should be cut off? Look at the 3rd last picture.
 
Hey Arlo,
If it was me, Id cut them off. If they are in the Magnet path they will be just making heat. Lets see if any one else has an opinion.
T
 
that is assuming the ends are not laminations....if they are laminated they should be fine.
 
Thud said:
Hey Arlo,
If it was me, Id cut them off. If they are in the Magnet path they will be just making heat. Lets see if any one else has an opinion.
T
Thats what i figured.. I think they are a part of the last lamination. I will look when i rewind it.
 
End Laminations.

If you aren't re-winding you can probably cut them off without changing performance significantly. They are handy to have if you are re-winding as they keep the wires from popping while you wind. They might not be highly electrive conductve, If they aren't you can just leave them there. If they are magnetic core (ferromagnetic) they they are actually performing work by directing the flux of the coils to the ends of the magnets, increasing the power of your motor. It is hard to say what value they are actually providing / sacrificing without looking at it.

Rotor Flux ring Thickness

A Neo42 magnet generally has a Br of around 0.95 Tesla, and Iron saturates at 2 Tesla.

Tesla is a unit of Flux Density, and since half your flux travels between magnet poles (1/2 goes to the magnet to the right, 1/2 goes to the magnet to the left) you want about the flux ring thickness to be about 1/4 the width of your magnet pole. (1/2 flux in something that can handle 2x the flux density = 1/4 the cross section)

Since you have 2 magnets making each pole, you want your flux ring to be about 1/2 the width of one of your magnets. I haven't read your thread that carefully, but it looks like your magnets are about 12mm wide, so you want about 6mm of flux ring. One way to tell if you have enough is to put a piece of iron on the outside of the flux ring, it should have almost no attractive force if you are at saturation, and no attractive force if you have more iron than that. A good design should have just a little more iron than saturation.

Also you mentioned that I said that Neo42 has higher temp ratings, and that isn't entirely accurate. High temperature Neo 42 has higher temp ratings than Neo52 or other high MGOe magnets. As you get higher temp ratings, your maximum energy Product (MGOe, i.e 42, 48, or 52 ) decreases, so you simply can't get Neo52 with higher than 80C ratings. You can still get Neo 42 with 80C temp ratings, but you can also get Neo42 with 150C Temp ratings, you have to be sure you get the high temp rating stuff if that is what you want (and I hope it is).

-ryan
 
Thanks Ryan. Very handy to know. I am building a second ring. So I will make it a bit different to help with those issues to build the best motor possible.
 
I almost didn't get it but..... Yup I lucked out and popsicle sticks were just the thickness the last one was a real..... SOB I used a tiny screwdriver to wedge between then two magnets and slide the popsicle stick in!
 

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I was a little worried about making sure I didn't get one magnet in with the polarity wrong so I got out the magnet viewer film and had a look.... I also double checked with another magnet and they look good!
 

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