Zappy's high power forced induction Magic Pie !

[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.

[zappy]

I used 4 jaycar electronics 50mm X 10mm fans. Part No. XC-5055 and yes i ground the corners off the very petite fan housing on the linisher. 8 would be even better! How are u going with your temp probe? It is interesting to monitor the winding temps. What are the max phase amps u are using? temps seen?

Zappy

[neptronix]

I used 4 jaycar electronics 50mm X 10mm fans. Part No. XC-5055 and yes i ground the corners off the very petite fan housing on the linisher. 8 would be even better! How are u going with your temp probe? It is interesting to monitor the winding temps. What are the max phase amps u are using? temps seen?

Zappy

The temp probe is real cool and i'm so glad i wised up to the whole idea. See my build thread in my sig for recent testing info.
Summary: i ran 3000-3500w constant for a few miles and it only got up to 120c without cooling holes or fans.

Going to take the same hill, same voltage tomorrow with cooling holes in a similar config as yours tomorrow. I'm curious if there is an improvement just from the holes alone.

Am running 60 battery, approx. 160 phase amps on an 18FET with 4115's. Can't get the controller warm....

[John in CR]

Neptronix, get radial blowers if you can. The flow of little computer fans is drastically reduced by restrictions nearby turbulence on either side, and radial fans are less affected. Take one and put your hand near it while running to get an idea. Plus the output of a blower is 90° to the intake, so you can blow it directly at the stator creating a more turbulent flow at it's surface, which greatly increases the convective heat transfer coefficient.

[neptronix]

Neptronix, get radial blowers if you can. The flow of little computer fans is drastically reduced by restrictions nearby turbulence on either side, and radial fans are less affected. Take one and put your hand near it while running to get an idea. Plus the output of a blower is 90° to the intake, so you can blow it directly at the stator creating a more turbulent flow at it's surface, which greatly increases the convective heat transfer coefficient.

Aahh.. thanks for the suggestion, but i just ordered the fans a bit ago.
They should run about 40-45CFM on my battery voltage when hooked in series.

Air should theoretically come in from the top of the freewheel side, and blow out near the center of the disc brake side, and there will be those little block off plates ( as in zappy's design ) to direct the air flow outwards.

[toolman2]

Neptronix, get radial blowers if you can. The flow of little computer fans is drastically reduced by restrictions nearby turbulence on either side, and radial fans are less affected. Take one and put your hand near it while running to get an idea. Plus the output of a blower is 90° to the intake, so you can blow it directly at the stator creating a more turbulent flow at it's surface, which greatly increases the convective heat transfer coefficient.

Aahh.. thanks for the suggestion, but i just ordered the fans a bit ago.
They should run about 40-45CFM on my battery voltage when hooked in series.

Air should theoretically come in from the top of the freewheel side, and blow out near the center of the disc brake side, and there will be those little block off plates ( as in zappy's design ) to direct the air flow outwards.

you dont want the air to exit at the middle, rather than fighting the natural flow to the outside diameter -best to help it along in that direction..
infact at 80kph it does seem like the fans are not helping much as the hub is its own air pump. -i can test this on a ride now i spose.
but the advantage appears to be 30-40% more torque (and power) ability at low speed where you need it the most, also we have all the data from dyno testing that we are happy to share, with and without holes and fans so save yourself that effort if you just want to get drilling.

ah yes john the limitation here for us is the intake side of the fans i think, they dont like anything coming within 10 or 20mm without buggereing the flow (you get that high revving no flow thing like a clogged vac) and the side plate is kinda in this space, so yep if you could find tiny centrifugal fans or something..
and its been 5 months of harsh use and the std fans are all ok with the high internal temps etc.

[neptronix]

I am actually looking to average about 40kph, since this will be a continuous 7% hill climb for about 11 miles.
So the pie has to handle 2500-3000 watts non-stop
On a 20" wheel, i will be running a lower RPM as well.

I was going to locate the fans right in between the edge of the cover and the disc brake mounting holes like zappy did.

If so, do you think the fans are going to benefit me, and... i do think that seeing the dyno information would be interesting if you can post it up here.

[John in CR]

Assuming a total load of 300lbs, 2kw at the wheel will get you 28mph and 3kw will get you 35mph. 35mph is plenty fast for good flow without fans, though I'd encourage a number of blades in each cover as close to the stator as you can get. I think it's an important factor in how well our ventilated motors are cooling....similar speed in a 20", bigger load so higher power, smaller diameter motor, and no heat problems.

Here's what I mean by blades (bolted and epoxied so they can't come off or loose and ruin the motor)
An example with a 9C

9C vented covers with blades.JPG (47.82 KiB) Viewed 187 times

More recently with Hubmonster (same diameter as a magpie)

SuperV with Hubmonster inside covers.JPG (46.58 KiB) Viewed 187 times

Unless I missed a change, Zappy has his 4 fans at the spokes of the stator with that aluminum sheet to seal the rest of the space off, so they help suck air into the swiss cheesed side cover. It's similar to what Arlo1 did, and I appreciate the benefit at lower speeds. Zappy is offroading, and Arlo does repetitive launches. I do think blowers, common for servers, would be far better. Mount the same way and point the output directly at the stator. You could also mount some with input and output on the same side of the motor to for a more turbulent flow on that side of the stator too.
This is what I mean by a blower, which would much more likely reach rated cfm in our use for motors.

Blower fan pic.JPG (8.16 KiB) Viewed 187 times

Unless I lose a bunch of weight and start off-roading, then I don't foresee ever needing to go active to ventilate my motors. If I did run into motor heating, the change I would make is larger intake holes near the center and a V shaped ducting outside the motor to funnel more air toward the intake. That would create a high pressure region there, which would definitely help intake flow.

John

[nechaus]

awesome!