FS Frame + Cromotor + Lipo

[sacko]

A great read, thanks for posting.

Could I ask where you got the bag from?

[gensem]

A great read, thanks for posting.

Could I ask where you got the bag from?

http://www.falconev.com/

[John in CR]

Is that paint or just black epoxy? I'm sure you know it, but you have to get down to metal and metal for bonding with surfaces made rough for the epoxy for it to mechanically have something to hold onto?

[gensem]

Is that paint or just black epoxy? I'm sure you know it, but you have to get down to metal and metal for bonding with surfaces made rough for the epoxy for it to mechanically have something to hold onto?

Its just epoxy John... no paint at all. It was all clean but not very rough. I think I ll use my greyborg frame to make as a reliable plataform.
Btw I have already removed the cromotor covers to do the intake on the left and outtake on the right perimiter, but now blades for the time being. I ll also close the holes in the stator so the air ll be forced to thru the magnet/lamination gap.

[John in CR]

Is that paint or just black epoxy? I'm sure you know it, but you have to get down to metal and metal for bonding with surfaces made rough for the epoxy for it to mechanically have something to hold onto?

Its just epoxy John... no paint at all. It was all clean but not very rough. I think I ll use my greyborg frame to make as a reliable plataform.
Btw I have already removed the cromotor covers to do the intake on the left and outtake on the right perimiter, but now blades for the time being. I ll also close the holes in the stator so the air ll be forced to thru the magnet/lamination gap.

I figured you prepared it pretty well. That was mostly for the sake of others reading, which typically lengthens most of my posts.

Don't close stator spokes all the way. That would starve the other side for air. I thought about closing mine some, but didn't. My thinking is the 2 sides are divided by the stator to a couple of inches from the perimeter. Then as centrifugal force increases the pressure on the intake side it has nowhere to escape but thru the magnetic gap to flow out.

Note that the warmest part of the outer shell is always the intake side near the perimeter....never hot, but warmer, so maybe I should block most of the flow space between the stator spokes, which is huge space on Hubmonster. Maybe estimate the cross sectional area of the magnetic gap and leave less than that open in the spokes since flow resistance is surely greater through the gap.

Blades are very easy, and I believe important. I'd at least do them on the harder to remove wire side, so you don't have to open it again. Tin snips, aluminum sheet, epoxy and a bolt. They can only help, and can't hurt. I don't think they increase flow, since the air spins at wheel speed no matter what. I do believe they greatly increase the effectiveness by essentially creating thousands of puffs of cooling air per minute directly at the stator. Without them the flow will obviously take the path of least resistance. ie along the covers, not the stator.

If you goal is to test both ways, I don't want to discourage that. I don't like opening my motors multiple times, especially with big new phase wires often making removal of the wire side impossible without rewinding.

John

[gensem]

I think i prepared it fairly well, but I wont deny I could do it better if I did it again. Even tho is was a hard hit, i think the aluminium would have bent if the epoxy was able to hold it together.

I ll make a draw (in mspaint, hehe) of what im probably going to the motor. I aim to run the cromotor with peaks close to 20k using a fan cooled 4110 24fet controller , so I cannot miss and make the hub ventilation half as good, it has to be very good.

edit: I was actually thinking of a way to create pressure in the intake side, so all the air flow in the gap (closed stator), but im not sure the air would have enough pressure. I was trying to find some sort of simulator but i was not able yet.

[nechaus]

What about using some hose clamps where you can..
just something extra just incase it fails..


I got some spare carbon fiber, if you want a bit i can send you some and you could use it to wrap around you joints...

[gensem]

What about using some hose clamps where you can..
just something extra just incase it fails..


I got some spare carbon fiber, if you want a bit i can send you some and you could use it to wrap around you joints...

Thanks for the offer nechaus, but I already got the greyborg warp frame out of the shelf and i ll start building a zippy bike with it. I still plan to do some more stuff with the fastrax glued frame but I really need a reliable bike to use in my daily commute.

Still need to find a way to flow alot of air in a thin gap....

[John in CR]

I ll make a draw (in mspaint, hehe) of what im probably going to the motor. I aim to run the cromotor with peaks close to 20k using a fan cooled 4110 24fet controller , so I cannot miss and make the hub ventilation half as good, it has to be very good.

edit: I was actually thinking of a way to create pressure in the intake side, so all the air flow in the gap (closed stator), but im not sure the air would have enough pressure. I was trying to find some sort of simulator but i was not able yet.

If the stator is closed then the other side of the stator doesn't get fresh air flow. With single side exhaust you're guaranteed some flow through the gap as long as you get the exhaust holes out at the same radius as the gap. At lesser radius the flow would surely be less and more complex in nature. Centrifugal force guarantees pressure. It's not big pressure, nor is it tremendous flow, but with the stator transferring heat to much cooler air it transfers much more heat.

The thing that drives me crazy about the all too common exhaust holes well away from the perimeter is how do they expect the hottest highest pressure air to flow out? I'm sure it mixes somewhat, but it's not a guaranteed inherent part of the gas circuit. You have a good handle on it, so I'm sure you'll get really good results, and it will reject heat drastically better than stock.

FWIW, hubmonster gets no warmer running at 30kw peak than it did at 16kw. If anything it's cooler, because the really high power flows for a shorter duration, and windings don't heat up instantly.

Something I haven't tried but my more recent research indicates could significantly increase flow is some type of air dam or cowling outside of the intake to both increase pressure in that region outside of the motor and to make it flow more freely into the intake holes. Without it we're trying to get air flowing by the holes turn to go in. I forget who brought that idea up in one of the threads but I researched it and it should increase flow pretty substantially. If I ever start having heat problems with a ventilated motor, I'll try that first, because making something to give it a try wouldn't even require taking the motor off, much less open it up. I bring it up in case you end up pushing your motor well into saturation, and need more cooling than I do, that there's still something quite easy to try.

I still think flow volume is just part of the equation, and what you do with the flow inside the motor is equally important.
I look forward to seeing what twists you add to the approach.

John

[hillzofvalp]

was just showing the eletrics of the bike to a friend and Im gessing i shorted the throttle wire or maybe broke the resistor.
The bicycle tried to fly and made a nice dive over its nose, breaking the epoxy and making me rethink about the epoxy holding so much weight right above the front wheel.

I'm willing to bet you have a current throttle through the ca. If you break the throttle input green wire going to ca the ca is not smart enough to detect failure of the wire and will gofull current. I told Justin about this in the v3 forum but people don't seem to see the need.

[gensem]

Yes, I was using current throttle... but i dont know if it was just the wire or if the resistor played its part. I ll not use resistors or pots in my throttle anymore.
Either way if a broken wire ll just make the go full throttle, CA really need some sort of security on that. I mean anything over 5kw is really dangerous in berserk mode.

[hillzofvalp]

I know. There should be logic for that and this logic is very easy to employ.

[Emoto]

Hi Gensem
Ive got a cromotor on its way, and will be putting it in a specialized big hit dh frame, should be strong enough.
Here is a interesting motor, notice the cooling holes location, and the ratio

[gensem]

Thats a very diferent hub design...
Cromotor should work very nice on your frame, my only problem with the alu frame i was using is that cant stop raising the power.
I just started my greyborg build and im following John's ventilation thread.
Plan on putting 10hp to the ground and to do that I think I will need about 15kw on the battery side(according to ebikes.ca simulator).

[Emoto]

The thing about that motor the cooling, along the lines john is talking about, its the first ive seen commercially.
Ive been reading you thread for a while good to see the testing/ evolution, so decided the Dh frames are a strong option
Im havent decided on forks double vs single clamp, single clamps will give a lighter build of course
I read you thinking of going single clamps yeah?

[hillzofvalp]

I am probably going to do something like this to my covers before I begin watercooling.. Because watercooling is going to require some serious down time.

I will probably just do one side because I don't have a gear puller right now. Which is the recommended puller again? Someone posted it to me but lost track

[gensem]

The thing about that motor the cooling, along the lines john is talking about, its the first ive seen commercially.
Ive been reading you thread for a while good to see the testing/ evolution, so decided the Dh frames are a strong option
Im havent decided on forks double vs single clamp, single clamps will give a lighter build of course
I read you thinking of going single clamps yeah?

I started simple and now I really that if you dont overbuilt it ll break (and potentially hurt you) when you keep pushing amps.
Longer swingarms and lower CG are mandatory for big power numbers.
I tought about a single clawn fork to use in my regular fs frame, but now that im using greyborg frame I ll use a DNM dual crown adapted to dual disk brakes (overkill as usual).

[gensem]

I am probably going to do something like this to my covers before I begin watercooling.. Because watercooling is going to require some serious down time.

I will probably just do one side because I don't have a gear puller right now. Which is the recommended puller again? Someone posted it to me but lost track

Any puller that is big enough to hold the covers will be more than enough.
I wouldnt use such big holes coz im scared of road debris in sao paulo. Also it would be better if you could create air flow through the stator gap.

[Emoto]

[quote="gensem"I started simple and now I really that if you dont overbuilt it ll break (and potentially hurt you) when you keep pushing amps.
Longer swingarms and lower CG are mandatory for big power numbers.
I tought about a single clawn fork to use in my regular fs frame, but now that im using greyborg frame I ll use a DNM dual crown adapted to dual disk brakes (overkill as usual).[/quote]

Thats right longer wheel base helps a lot, this helps on my supermoto [modified] dynoed @ 62hp rear wheel, but having the front wheel come up is also mandatory imo.
What is the model of your michelin rear tyre @ 23" od

Hillzofvalp i envy you having access to milling equipment.i use to but not atm
Just a thought i would have smaller holes more evenly distributed

[hillzofvalp]

I was thinking of using some type of mesh to keep particulates out. A little dust doesn't hurt. I would have thought that larger hole is better... And think that it should be reconsidered. Mst people haven't tested large because most people don't have the capabilities to make these modifications

[Emoto]

More holes evenly displaced would radiate heat better at rest , as you know temps can rise then with no movement/ flow of air.
Saying that experimenting is a good thing, so go for it, put a temp probe on her for before and after results, do you know how much a replacement cover is.
Not thinking about the problems with dust and stones, it would be nice to mill it like a mag wheel ow and then get it anodised

[gensem]

24fet controller Hi CFM fan




Biffed traces




Hoping to have something running in a couple weeks (29/07 probably)

[hillzofvalp]

I am genuinely excited for you. Can't wait to see how air cooling helps on the motor and your take on a hole patttern

[gensem]

I forgot to ask...

The controller is fitted with 24 4110 fets and I dont plan to go over 160a main;
Should I mod anything else on the controller?

[John in CR]

I forgot to ask...

The controller is fitted with 24 4110 fets and I dont plan to go over 160a main;
Should I mod anything else on the controller?

When i ventilate controllers, I direct the airflow where it's needed, just like I try to do in a motor, because the path of least resistance typically isn't best, eg Once the board is in the case I use a doubled up piece of shrink under the full width of the board to stop air from flowing under the board. On the component side of the board I mostly block off the mostly open side. I put the intake holes near the FET bar(s). My goal is to force the air flow from the fan toward the FETs as much as practical, since they're what is generating all the heat. It can make a huge difference too. On the Super 36 I got from SteveO, he had really swiss cheesed the intake end cover plate, and air flowed freely, but the air coming out didn't feel very warm even when the case near the FET bar holding bolts what quite hot. I blocked off the intake holes except near the FET bar, and the air coming out got noticeably warmer. Then I did my usual air dams inside and the exhaust air got warmer still, so I know both portions of the approach are beneficial.

You also have to be sure that you have sufficient intake area, especially with radial fans which usually can't put much pressure at all without high power like a ducted fan. The way I make sure is to run the fan with the end all the way open and with the end plate on to be sure the flow volume doesn't change. Feeling it with your and and listening to the fan sound have worked sufficiently for me.

When it's for a bike to be used in the elements, I use short pieces of 3/8" tubing for the intake and angle them down and forward. That way water or debris would have to go uphill to get in the controller, and there's just not enough flow velocity. Another benefit is that I can direct the inside end directly at the fets. It does take more cross-sectional intake area though, since the tubes themselves represent a flow restriction.