Re-wind of a turnigy 80/100 (Now-tutorial w/Video)

Thanks for that link Spin,
You have re-discovered my favorite reference site. That used to be linked through the "go brushless" website & was my first exposure for motor desgn & building...thought it was lost forever...I been searching for it.

Hi,

do you think it would be possible to rewind a 130kv for 230kv ?

actually i have 6kW solid rock out of a 180kv,
i would like to use the 11 000 rpm maximum rating of the skirt bearing as a top speed limit with 48V nominal.

thanks,
Phil

The answer is yes, but...from my experience you will be deep into iron loss on the stator at those RPMs. I've logged a dramatic spike in motor temprature starting @ 9k RPMs...even unloaded.

Toolman2 has also verified the reasonable RPM limits in one of the motor comparison threads.

The 180 Kv seems ideal for a 48V limit.
Prolly not a good idea to run the bearings at their max limits either.

thanks ... what spike and iron loss % level are we talking about, do you have date curves please ?
11000rpm max not sustained is ok, i'm using SKF bearings not low cost original ones.
Actually under high stress motor is just warm (hand touch without problem) so i think temperature can goes up a bit, cooling is efficient enough.

what would be the wiring you would advise please to obtain lets say 220kv and 6 to 7kW peak few seconds ?
Phil

vehiculeselectriques said:

thanks ... what spike and iron loss % level are we talking about, do you have date curves please ?
11000rpm max not sustained is ok, i'm using SKF bearings not low cost original ones.
Actually under high stress motor is just warm (hand touch without problem) so i think temperature can goes up a bit, cooling is efficient enough.

what would be the wiring you would advise please to obtain lets say 220kv and 6 to 7kW peak few seconds ?
Phil

Click to expand...

What Todd is trying to tell you is you will be wasting your time spinning it past 9000 rpm. At 9000 rpm the eddy currents in the stator laminations are so hi it makes the motor hot just spinning 9000 rpm unloaded. Eddy losses go up at the square of the rpm so at 11000 rpm you have 49% more heat than 9000 rpm so basically just simply spinning it 11000 rpm unloaded will likely fry the windings in short time and use a very high amount of power!

I can't find the graph for the 80-100 motors toolman plotted.....but this is a close example:
http://endless-sphere.com/forums/viewtopic.php?f=30&t=43306&start=25#p667236

As Arlo1 says, these motors generate induction heat exponentialy at rpms above 7k....I wind, volt & gear my performance set ups into the sweet spot around 7-8k rpms.

30 seconds at 13k gets them stupid hot under no load...with the magnets getting "permanent damage" hot.

Hi

thanks a lot for your advise ... though
i'm racing so going near or beyond melting things point is acceptable trade for having higher performances :wink:
there is C8085 250kv and this one 220kV goes up to 55V, 12000rpm ! so what is it's secret, the fan ? i have such fan also even better it's Thud advanced design !
how to reduce eddy currents for going upper 9000rpm reasonable limit ?

so my question about the best wiring for 220kV remain :wink:

Phil

Ok phil,
I have to ask...What are you using for a speed controller?

An 80-100 wound with 5 turns 3-in-hand 15-awg wire, terminated delta will give you 212-Kv.
Wound with 4 turns, 3-in-hand, 14-awg, delta...will put you at 265-Kv..

Those suggestions are about the best I can wind onto the 80-100 stators.
If you're serious about max power, forget the 80-85. It is only 70% of the bigger motor... + more copper loss with the increased % of end turns. Bigger wins the HP race every time.

If your going to load these things down in a racing scenario I would design a slipper clutch into your drive line, so you may adjust the absolute maximum load the motor can draw. Even if its an outboard motor...your going to need a monster controller to feed these lil' monsters.

Have fun & good luck.
& please do keep us updated on your progress.
I luv's me some racing

Edit:
Reading thru a couple of your posts, looks like your running a XieChang (ecrazy man) controller. You are going to be having some throttle cutting issues with a hot wound motor listed above.

You may have to mod the current sensing circuit to get the function your looking for. Depending on the board version...you are going to need to change the value of the R43 (if the qf1 transistor it populated) or the R44 if otherwise...I used to add a resistor across the c20 capacitor, but newer boards have not had that section of board populated.
There are schematics here:
http://endless-sphere.com/forums/viewtopic.php?f=2&t=16910&start=25#p252810
Are you comfortable with electronics?
I only know enough to be dangerous...& then look really stupid :lol:

thanks a lot for your help Thud
i'm already racing with a 180kV SKF mounted and EB212 upgraded controller ...
48V and 137A max on the watt's up
i have enough acceleration but need more speed !
I have a couple 130KV to rewind and will try your 212kv solution, should be a good compromise reading Arlo1 and your advises carefuly.

may i ask if there is a wiring solution for 210-220kv WYE termination which would still permitt 7kW ?
WYE should give best efficiency right ?
3 turns WYE should be near equal to 5 turns Delta, am i right ?

Phil

has probably been asked and answered but i cannot find any info anywhere, how is the KV pr wire turn for the 8085 motor?
As im almost finished with my DM50 i going to join all of you an make an E-bike instead of moped, i want something with more range for same battery and MORE SPEED!!!! , the mopeds i have made is to conform to 30'ish KM/h

8085---
9t delta = 140kv ,8t delta = 180kv , 7t delta=212kv,
9t wye = 79kv , 8t wye = 101kv , 7t wye = 120kv


Edit: no cutting out ( or over heating probems ) with a 12fet tested upto 160A (@48v) battery current as long as the timing is spot on..

Very rough 80-85 winding Kv

6 turn = 250-Kv delta
8 turn = 170-Kv delta

Keep in mind the 80-85 is a relatively small motor, & speed kills range.
Not sure what your expectations are...but for me, its a tiny motor

This motor will develop its maximum power density spinning at 9k rpms. Any rewinding/re-terminating will need to be voltage adjusted to keep in that RPM range.

If you're looking for a suggestion. Try a 2-in-hand, 14g, 7-turn & terminate wye...the Kv will be 120 ish.
Give it halls & Feed it 72volts...keep the power levels in the 5-Kw range have some fun.

Edit: I see gwhy gave you some good info.

Thanks for the fast response , i was actually looking to UP the KV to around 400-500KV but i don't know if this will kill performance, of course i could leave it at 250 an run 40-50V to 8000+ RPM under load, which is the best route in your XP?, 22.2V and AMPS!!!! or 40-50V and amps.

Realistically, this motor will only run 5-Kw with a little headroom for burst acceleration.
If I ever get time to build a proper dyno, we could know the saturation point...where more power in is just wasted energy.

With limited controller options, it is just easier to handle voltage over amperage.

5000W @ 72V is 69-amps
@ 48V its 104A
@24V you will be pushing +200 amps

For that your looking at huge wire, connectors. Just paralleling batteries to deliver that rate for any meaningfull time is daunting (to me anyway) to handle high amperage correctly.

Then there is the controller issue....not many out there that will deliver 200-amps for more than a few seconds burst.
Re-winding for super high Kv will drop your inductance & make the motor very "stiff" for the poor FET's in any controller.
Dont confuse phase amp levels with power delvery.

If your serious about making horsepower...get ready to spend some $$$.
Mostly because any mistake at higher amperage levels are exponentialy more damaging to componetry.

Like any junkie, these PM motors crave amps...& will be happy to suck down every one they can find...you need to be "daddy buzz-kill" & only give it enough power to keep it & its partner (controller) this side of thermal overdose.

You can chart your own path....but for me, its volts over amps when pushing the performance envelope...

Thud said:

.but for me, its volts over amps when pushing the performance envelope...

Click to expand...

Todd its a even number or square. like the 2 strokes found a even bore to stroke number would work its the same with amps to volts. This it my work/research/gut feeling! Take it with a grain of salt.

well am also leaning more to the 50V setup instead and keeping the motor stock at 250KV, im actually looking at using less the 5KW for this build, and yes winding the motor with VERY few winds and VERY thick wire will be quite a stress on ESC, to start with im just buying the motor and using the things i have in stock, have several LiPo's and i have my battery i used for the Ciao and using for the DM50.

as stated i really want to go light weight and fast, also im adding a limiter to limit throttle to make the bike go 20-30 Kph to make it look like im just cycling

Will post a thread when i start in a weeks time.

Thanks again guys, sometimes you get into a bit of doubt and it is good to get more opinions and especially from some of you that have really done some work into these motors, my ciao was "stock" 200KV and my DM50 is the first outrunner where it has been rewound (68KV), and it is GOOD, i might only have around 2500W for acceleration but it goes nicely and on long trips it is COOL as ICE, less then 40c on the last "long" run.

A few years ago Thun made me a c80-100 motor with a 55 kv winding with hall sensors. I still didn't use it, but now I will for a new project.

Do you think I can run the motor sensorless with a greentime 24 fet sensorless controller ?

Would a hall sensor controller be better ?

Thanks

Bazaki said:

Do you think I can run the motor sensorless with a greentime 24 fet sensorless controller ?

Click to expand...

yes

Bazaki said:

Would a hall sensor controller be better ?

Click to expand...

In a EV, a lot better!

Direct drive under water with boat prop at surfboard. So no stalling or heavy load at low rpm.

in that case its ok, apart from slow accelerator response when the motor is stopped

Bazaki said:

Direct drive under water with boat prop at surfboard. So no stalling or heavy load at low rpm.

Click to expand...

I have thought about that as well. Another idéa I have (which won't work on a surfing board) is to mount the motor on a planning hull, above the water at planning speeds, with a surface piercing prop. Then the rotor won't cause any resistance, and the motor should still get enough cooling from water spray. A small catamaran with dual motors would be nice.

Good idea, but a surface prop will probably make very much noise, with a lot of water spray and woud look like a gasoline driven motor. I can't use that.

Hi all,

When I dissamble my motor I don't how to dissamble the skirt bearing and the skirt bearing housing. Like below, how is this possible ?

Thanks

[/quote]

Bazaki said:

Hi all,

When I dissamble my motor I don't how to dissamble the skirt bearing and the skirt bearing housing. Like below, how is this possible ?

Thanks

Click to expand...

[/quote]
I do not know what you mean, but:
1)Unscrew 4 alen bolts on the stator cap (where cables come out), remove cap
2)Remove spring ring (do not know exact term) holding the axle in place, do not loose brass ring under the cap.
3)unscrew little alen bolts on the rotor can to outer skirt bearing fixture, remove fixture with skirt bearing.
4)Remove stator out of the can and axle (magnets will try to hold it in place, I usually slide/pull stator down the axle holding on something fixed with bolts where cap was fixed)
If you want to remove anodized layer like on the picture, remove 2 axle bearings first (you can see those on the picture). Inner skirt bearing fixture is part of the stator, beeng pressed in to lamination stack.

I dissambled the motor many times, but It seems to be impossible to remove the skirt bearing and housing like at the picture, I will try your number 4, I did not remove the shaft bearing.

I have to get to the point where the windings are soldered to the phase wires, I need to waterproof the whole stator. I plasti dipped it many times but I can't get it waterproof behind the skirt bearing housing.

Any idea's how to waterproof this ? Epoxy is a bit risky because it permanent, and plasti dip is a bit weak.