Zappy's high power forced induction Magic Pie !

[neptronix]

Originated from this thread, but posting to a separate thread to prevent hijacking..

http://endless-sphere.com/forums/viewtopic.php?f=2&t=38200&hilit=magic+pie



















Quite badassical if you ask me, i love how air is sucked in @ the windings and blown out.. Zappy says this provided a great improvement in power handling & now i'm inspired..

Hey Toolman2, i'd like to see what you've done

[amberwolf]

Interesting--at least now we can see that someone has indeed done a fan cooled MP.

If I were to do something similar, I would use larger fans, the very largest that would fit between axle and stator ring, as that will give significantly more airflow for energy usage and noise, and I would use a few much larger holes instead of the multitude of smaller ones on the left cover, because the smaller a hole is, the more turbulence around it and the less air that can easily flow thru it.

Would be interesting to see what difference this would make to temperatures inside his hub.

[liveforphysics]

I love his simple conversion to allow large phase wires to fit. I really love this forum and its amazing members.

Great work Zappy!

[zappy]

Thanks very much neptronix for posting up these pics!

I think a similar version of the thin bearing hub sleeve adaptor may be very useful for other brand hub motors as well. Most standard phase wires are small, untinned with very thin insulation to fit in this very busy area which get very easily damaged from changing wheel/tyres, rear disk brakes and rear suspension travel pivots etc. The standard hall wires are also squashed hard up against the hot high current AC phase wires in the standard axel slot. This bearing sleeve gives a bit of space so you can run 8 guage silicon phase wire, shielded hall wires ,fan wires, and temp probe pickups. Make sure the sleeve is a press fit on the axel and or use a grub screw to stop it from spinning and cutting off your wires. It is easy to make and the bearing cost only a few bucks on ebay. The fans are mounted on a piece of 1mm aluminium and tapped(M3) into the hub spokes. toolman2 and i discussed using 6 or 8 fans but we didn't know how long these would last in this hot, VERY rough, sometimes under water enviroment but they seem to be holding up ok. I totally agree bigger fans move heaps more air but fan thickness is tight and it was just a starting point. My first magical pie i drilled 1/2' holes in and i dropped a disk bolt down the hole which stuck to the magnets and i had to pull it apart so lots of small holes with a similar cross section to fan cross section was seen as a practical compromise to help keep bolts and the bigger rocks out. With all the holes in the side covers the pie cooling plate with 4 fans weighing only 135g ive probably lost weight all up. I think having holes right at the edge of the pie plate near the copper maximises centrifugal air flow outwards and water can not collect. Toolman2 is the brainstrust with the wye/delta conversion and has info about the dyno and torque and temprature torture tests carried out. toolman2 has been running magical pies for years and runs a clone to this with more volts and an 18fet controller. Any questions please ask

Zappy

[Pure]

That's an awesome thing you've done. I wonder though, if you have any pics of it on the bike from the wire bearing side? Just would like to see how you routed all that around the drop out.

[o00scorpion00o]

Excellent stuff

[MitchJi]

Hi,

My first magical pie i drilled 1/2' holes in and i dropped a disk bolt down the hole which stuck to the magnets and i had to pull it apart so lots of small holes with a similar cross section to fan cross section was seen as a practical compromise to help keep bolts and the bigger rocks out.
Zappy

Why not larger holes, covered with screen or mesh?

[auraslip]

In the other thread you say the motor is around 13kv when in delta configuration with a phase resistance of .065ohms.

That sounds pretty awesome. In swblutos simulator with a 90v battery pack, this motor looks like it'll do 0-60 in about 12 seconds. While dumping almost a kw of heat into the motor

How hot does it get in normal operation? What are some heating figures?

[John in CR]

Great work Zappy! I'm trying something new with a similar large diameter motor that has a 50mm stator, which I hope to reassemble tomorrow. The difference is one sided exhaust on this one. My thought process is to get more air flow through the air gap, so I intake on one side and exhaust at the very perimeter on the other. I've got blades on both covers near the winding to create more turbulence at the windings and stator iron, and to ensure a high pressure region at the perimeter on the intake side to force air through the air gap to exhaust.

Personally, I don't think fans are needed, especially with a large diameter motor along with a small wheel for more rpm. Since you have a temp sensor can you put it to the test and make the same sufficiently long runs with and without the fans on? Your flow restriction across will hurt the fan off results somewhat, but I doubt too much except at very low speeds. Please put me to task when you get a chance. On mine I've got cavernous space, so plenty of room in the spokes, though I'd use centrifugal fans like used for servers if I ever get enough controller to get this motor hot with my natural ventilation approach.

Thru mud and water deep enough to get in the motor??? I hope it proves durable for you. Were you able to butt your exhaust vents against the magnet ring lip, so anything getting in there will flow right back out? Judging by the dirt it looks like you're having lots of fun with it.

John

[amberwolf]

Why not larger holes, covered with screen or mesh?

Adding the screen or mesh does the same thing as having lots of smaller holes--significantly decreases airflow by increasing turbulence caused by interaction with the edge surfaces.

To see this effect, if you have a screen door and a windy day that would blow thru the house, open all the doors/windows at the other side of the house. Then open the main door at the opposite side of the house, leaving the screen closed. Note the airflow, and then open the screen. The airflow should increase dramatically, especially in the center of the doorway.

To see the equivalent of using the same surface area of large hole to smaller ones, you could calculate how much area is covered by the screen mesh itself, and then use a solid sheet of something to block that much area of the open doorway.

[nechaus]

Oh man i hope you post some more pics and videos

Please if you have the time, record a smoke test on the side of the motors when the fans are on.
id be interested to see if this is worth while.

Iv been thinking of either fan or oil cooling for sometime now.
Getting a bunch of hubs soon to try both cooling methods

[auraslip]

I have some questions about running the pie in delta mode.

Usually this decreases torque right? How does this work with the pie?

Do you leave it in delta all the time, or have relays to switch it?

[toolman2]

Oh man i hope you post some more pics and videos

Please if you have the time, record a smoke test on the side of the motors when the fans are on.
id be interested to see if this is worth while.

Iv been thinking of either fan or oil cooling for sometime now.
Getting a bunch of hubs soon to try both cooling methods

yes a smoke test sounds great, ill have get phillistine to help with this one..
in recent news, zappy seems to have run into a bit of trouble, he ran the controller up to 8kw in, was doing i sic mono at decent speed, then remembered he had
removed the rear brake, now on crutches.
anyway ill let you tell the story when your feeling up to it zappy, and dont forget my favorite bit, the kids finding daddy passed out from pain and pantless on the tiles afterwards.

[Pure]

Sounds like a scene out of Jackass. lol

Get well soon Zappy!

[neptronix]

That does not sound pretty. Best of wishes with the recovery, zappy. I hope we hear from you again.

[neptronix]

Hey Zappy.. I'm thinking about running double the fans you run.. 40mm x 10 times 8.. a bit more CFM.. maybe not necessary, but why not, lol.

But one question.. did you have to worry about the temp ratings of the fans?

[zappy]

The fans have been perfectly reliable so far. This same magic pie winding has thousands of km's of very rough riding and sustained dyno runs holding constant 150 degree C testing and at 8kw in, and has seen 210 degree for a few over exuberant seconds(very wrong). I think it would be a big improvment to add more fans but a huge increase in flow would be to use bigger diameter fans. Hub motors make the most heat when max cotroller phase current amplification is taking place! ie: zero to low speed while at the same time have the least ability to get rid of the heat. Cruising at high speed the motor is 80% efficient and passive air flow with drilled side plates is usally enough. I encourage people to try this fan mod and or improve it. It is cheap and effective where hub motors need it most, at low speed and quickly bringing the temps down before the next assault and cool down heat soak of magnets. Toolman2 and i have measured a 45% increase in power output at 100% duty cycle with this fairly lame effort for only 10w of power!

Zappy

[liveforphysics]

Zappy! We need to hear more about this! I want some carnage pics!

in recent news, zappy seems to have run into a bit of trouble, he ran the controller up to 8kw in, was doing i sic mono at decent speed, then remembered he had
removed the rear brake, now on crutches.
anyway ill let you tell the story when your feeling up to it zappy, and dont forget my favorite bit, the kids finding daddy passed out from pain and pantless on the tiles afterwards.

[zappy]

Yes i did faint naked on the stone bathroom floor banging my face up and exposing my teenage daugter to much nutage. PM sent

Zappy

[Pure]

hahaha that's hilarious zappy. The teenage daughter part not the you hurting yourself part.

I'm all too familiar with getting hurt on an e-bike. I start PT this week for my destroyed shoulder/arm.

Get well soon brother.

[voicecoils]

yes a smoke test sounds great, ill have get phillistine to help with this one..

ahahahahaha

p.s. sorry to hear you stacked it Zappy

[Brentis]

Yes i did faint naked on the stone bathroom floor banging my face up and exposing my teenage daugter to much nutage. PM sent

Zappy

Sorry to hear of your injury.
Consider yourself lucky though, your injuries will heal long before the nut trauma your teenage daughter has faced.
Some girls just never recover.

Get well soon, the both of ya'.

[zappy]

neptronix these fans might fit??

4 of these IP55 80mm 12V DC Ball Bearing Fans [YX2523] 20mm thick.
maybe a bit of a squeeze.

Zappy

[neptronix]

neptronix these fans might fit??

4 of these IP55 80mm 12V DC Ball Bearing Fans [YX2523] 20mm thick.
maybe a bit of a squeeze.

Zappy

Good question. I just got my bike up and running ( yeah!!! ) I am going to start doing some hill runs once i get my 24" front wheel set up, record the max temps, drill holes, run up the same hills, add fans, do the hill run again etc. I want to do this scientifically.

I want to run 8 fans in series so i think 80mm is outta the question. Also, keeping them away from the 100-150deg. copper might be smart too

[neptronix]

Looks like the biggest fan you can fit is 45mm, or 50mm if you can grind off some edges.
The tallest fan you can run is 15mm.

So 8 x 50mm x 15mm fans would be maxing this sucker out.

I am going with 8 40mm x 10mm fans tho.