hillzofvalp
100 kW
Update: I am implementing water cooling channels in my cromotor, with the possibility of an oil bath as well to supplement the water cooling. Scroll all the way down and skip past the video of milling the stator on CNC machine.
HoV's Exploration of Water Cooling w/ Oil Bath (Cromotor)
- Thread starter hillzofvalp
- Start date
hillzofvalp
100 kW
or I could make something similar to what HAL9000 made but never got around to trying... (or sharing). Below is about .85 lbs. Maybe one for each side. This shows a continuous 6.604mmx26mm cross section (.26" using .25" endmill).In practice it would be more like 18-20mm deep with top and bottom modeled. The inner M4 holes would clear the 6 holes in the stator, so the whole assembly could be sandwiched in or removed fairly easily.
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HAL900v2.0:
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HAL900v2.0:
hillzofvalp
100 kW
I made some measurements of the axle channel and then made it a tad smaller to be conservative. Lots of room to work with when taking to 30mm from 25mm ID. I would probably fit more copper in with custom bundle made of high strand count deans or something similar. THen again, are overly huge phases really necessary when you're water cooled?
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TylerDurden
100 GW
Bit of a loaded question: "overly huge". That aside, large phase wires will heat less, carry more power to the coils.hillzofvalp said:
hillzofvalp
100 kW
I get you.. I just think it's amazing to see people with 6AWG phases running in their motors. maybe 8AWG would be something to shoot for. On my motorcycle, they will only be 3 feet or so long...
I guess the thermal path from the phase wires to the windings is not the best for them to be cooled as a result of liquid cooling the stator base, so huge phases will be considered, but I would have to do a lot of modifications to accommodate 6 gauge
edit: my sketch above has two main issues. I'll let you guess the silliest one yourself.. but the other, more important concept, is that the flow really needs to just pass along the edge... got a little carried away.
I guess the thermal path from the phase wires to the windings is not the best for them to be cooled as a result of liquid cooling the stator base, so huge phases will be considered, but I would have to do a lot of modifications to accommodate 6 gauge
edit: my sketch above has two main issues. I'll let you guess the silliest one yourself.. but the other, more important concept, is that the flow really needs to just pass along the edge... got a little carried away.
hillzofvalp
100 kW
Couldn't the above cooling channel sketch actually be good if it back tracks to the axle every 30 degrees? It would work to distribute the heat more efficiently rather than just through a straight path along the perimeter (like HAL9000's).
hillzofvalp
100 kW
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hillzofvalp
100 kW
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I began to mill the cover for a larger 55mm bearing today.. I was hesitant to do the full cut until I have the bearing on hand
. But now there is no going back.
I probed multiple points on the flange and found that the part was fixtures about .016 degrees from perfectly orthogonal to machine at worst.. which isn't bad!
I began to mill the cover for a larger 55mm bearing today.. I was hesitant to do the full cut until I have the bearing on hand
. But now there is no going back.I probed multiple points on the flange and found that the part was fixtures about .016 degrees from perfectly orthogonal to machine at worst.. which isn't bad!
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hillzofvalp
100 kW
Also, I am looking into making a spacer/bushing to go from 25mm to 30mm ID bearing, but I'm wondering if any of you think it's okay to buy a SAE 660 (alloy 932) bronze sleeve bearing and modify it for my application. It's only $5-10.. but would it really be strong enough?
http://www.metals4u.co.uk/SAE-660-Bronze.asp
http://www.mcmaster.com/#catalog/118/1128/=j1da52
OIL COOLING
what If I made an oil bath and then pumped the oil out of motor to intercooler? Why-- that's a great idea!
http://www.metals4u.co.uk/SAE-660-Bronze.asp
http://www.mcmaster.com/#catalog/118/1128/=j1da52
OIL COOLING
what If I made an oil bath and then pumped the oil out of motor to intercooler? Why-- that's a great idea!
hillzofvalp
100 kW
I think one channel is best, like HAL9000 did. The one below has a continuous cross section, but 3x larger than before.
What do you guys think of having a fluid cooling ring on each side of motor like keyne's and hals, but then also doing an oil bath and making something to splash the oil onto the ring. I picture little off-shoots from the ring that dip down into the oil bath.
I figure implementing an oil-only solution in which the oil is sucked out and cooled externally would be a pain in the ass... and pump might not like air eevry now and then.
updatE: okay so here's the deal.. It would either be one 20mm ish deep pocket with a cover or two halves (one halve pictured). The advantage to the latter is that I can machine half the hole to be tapped for the fitting, then assemble it, then tap it by hand. Wouldn't worry so much about cover clearance. It would also allow a direct route out of the motor. The other method might have less chance to leak.. maybe quicker to mill too.
What do you guys think of having a fluid cooling ring on each side of motor like keyne's and hals, but then also doing an oil bath and making something to splash the oil onto the ring. I picture little off-shoots from the ring that dip down into the oil bath.
I figure implementing an oil-only solution in which the oil is sucked out and cooled externally would be a pain in the ass... and pump might not like air eevry now and then.
updatE: okay so here's the deal.. It would either be one 20mm ish deep pocket with a cover or two halves (one halve pictured). The advantage to the latter is that I can machine half the hole to be tapped for the fitting, then assemble it, then tap it by hand. Wouldn't worry so much about cover clearance. It would also allow a direct route out of the motor. The other method might have less chance to leak.. maybe quicker to mill too.
Attachments
hillzofvalp
100 kW
I might run a prototype ring this week. I decided to first use my old 9C for practicing the CNC milling of the stator. It also might be a similar or exact diameter to the cromotor.. so hopefully that will be useful for modeling purposes.
One of my big questions about the milling process is concerning clearance of the copper bundle on one side of the motor. I figure there is a safe way of compressing the bundle radially.. I only need to move it about 3 mm so the endmill doesn't nick it. Anyone have any advice here on compressing the bundle in outward radial direction? It is currently wrapped with string and has a little bit of fiberglass sleeving on some of it. (seen in pics)
From HAL's pics, it looks like he took off as much as .05" which seems like a lot.. but it would decrease the thermal barrier. I wonder what mechanical implications exist, and, if it is significantly advantageous to take off more steel, what workarounds can be made to any introduced mechanical problems.
One of my big questions about the milling process is concerning clearance of the copper bundle on one side of the motor. I figure there is a safe way of compressing the bundle radially.. I only need to move it about 3 mm so the endmill doesn't nick it. Anyone have any advice here on compressing the bundle in outward radial direction? It is currently wrapped with string and has a little bit of fiberglass sleeving on some of it. (seen in pics)
From HAL's pics, it looks like he took off as much as .05" which seems like a lot.. but it would decrease the thermal barrier. I wonder what mechanical implications exist, and, if it is significantly advantageous to take off more steel, what workarounds can be made to any introduced mechanical problems.
hillzofvalp
100 kW
I milled the cromotor stator today! 6907 bearing from mcmaster came in and ended up being Japanese... Probably good. This is a 35mm x 55mm x10mm bearing which I chose over the 35mm x 55 x 11. The original bearing was 25 x 52 x 15 and was rated for someting over 3000 lbs... But was Chinese. The replacement is rated for around 2500 lbs. should do the job.
The hope is that I can fit in 3/8" OD hoses instead of 1/4". Need to update model.
So I milled the stator today.. But I was In a hurry and didn't get the best surface finish (tool was way too long and stator wasnt rigid enough. The ring edges are concentric so pressing them in will be easy... Any recommendations for polishing the steel on stator before applying thermal paste?
I keep Smiling over how big the Contact patch is ...about .2745 m^2! About 80-86% of stator width. I'll upload some pics and video of the milling tonight
The hope is that I can fit in 3/8" OD hoses instead of 1/4". Need to update model.
So I milled the stator today.. But I was In a hurry and didn't get the best surface finish (tool was way too long and stator wasnt rigid enough. The ring edges are concentric so pressing them in will be easy... Any recommendations for polishing the steel on stator before applying thermal paste?
I keep Smiling over how big the Contact patch is ...about .2745 m^2! About 80-86% of stator width. I'll upload some pics and video of the milling tonight
hillzofvalp
100 kW
I'm upping a video right now.. Every time I make a video in iMovie I usually over do it.. but it's fun, so...
[youtube]m_GofIWB1Hs[/youtube]
By the way, I was reading around about opinions on water cooling the stator and its effectiveness and wanted to offer my current stance. Yes, steel in stator has poor thermal path to windings. One would argue air cooling would be the same effect or better. However, I think that with a high enough flow rate and efficient enough radiator, the motor will tend to be lower in temperature. It may not be able to handle spikes like air might because of its good surface area and getting s traight to heat source, but the cooling rings will pre-chill the motor when it is operating under the continuous rating of the motor (say <3kW). air is limited by weather.. where water cooling is less dependent because water has such high specific heat. To demonstrate, take a motor which has cooled to 25C. Start blasting it with air from all directions. Then take another motor with water cooling and turn up the flow. The result? Water cooled motor brings temperature down to say 20C. It has the benefit of a greater buffer. Air cooling would stay very close to the same temperature unless it was very humid outside.
If it does not perform well with high flow, lots of steel-aluminum contact, or a good radiator, I will attempt to splash oil in oil bath upon the ring (probably by incorporating a little copper dipstick that is submerged in motor lowers).
Keyne was able to achieve I believe a .5-1.5C/sec cooling rate on his 6kW 9C and never broke about 130C which is amazing. I ran my 9C at 3.5kW and it was smoking after ever run (obviously different conditions in 29" wheel).
[youtube]m_GofIWB1Hs[/youtube]
By the way, I was reading around about opinions on water cooling the stator and its effectiveness and wanted to offer my current stance. Yes, steel in stator has poor thermal path to windings. One would argue air cooling would be the same effect or better. However, I think that with a high enough flow rate and efficient enough radiator, the motor will tend to be lower in temperature. It may not be able to handle spikes like air might because of its good surface area and getting s traight to heat source, but the cooling rings will pre-chill the motor when it is operating under the continuous rating of the motor (say <3kW). air is limited by weather.. where water cooling is less dependent because water has such high specific heat. To demonstrate, take a motor which has cooled to 25C. Start blasting it with air from all directions. Then take another motor with water cooling and turn up the flow. The result? Water cooled motor brings temperature down to say 20C. It has the benefit of a greater buffer. Air cooling would stay very close to the same temperature unless it was very humid outside.
If it does not perform well with high flow, lots of steel-aluminum contact, or a good radiator, I will attempt to splash oil in oil bath upon the ring (probably by incorporating a little copper dipstick that is submerged in motor lowers).
Keyne was able to achieve I believe a .5-1.5C/sec cooling rate on his 6kW 9C and never broke about 130C which is amazing. I ran my 9C at 3.5kW and it was smoking after ever run (obviously different conditions in 29" wheel).
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hillzofvalp
100 kW
For the two halves design to work well it would need to have more CNC programs to run than a simpler design like HALs. I have decided to go to the 24mm insert route with a lid that has pad on it that mates with the channel profile to give a nice seal and support the 2mm outer wall.
I like the old two-halve design because of a convenient hose exit but also because it allowed the stator walls to act as a seal.
prototype... might make something like this this week. inlet/outlet now are coming out of the page.. hopefully 90 degree barb is low profile enough to not hit cover... Insert lid will be about 1.5-2.5mm below the height of the copper windings.
And.. YES, THAT is a GOLD plated nickel I found in circulation.. the bank tellers here said they never saw one before...
I like the old two-halve design because of a convenient hose exit but also because it allowed the stator walls to act as a seal.
prototype... might make something like this this week. inlet/outlet now are coming out of the page.. hopefully 90 degree barb is low profile enough to not hit cover... Insert lid will be about 1.5-2.5mm below the height of the copper windings.
And.. YES, THAT is a GOLD plated nickel I found in circulation.. the bank tellers here said they never saw one before...
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hillzofvalp
100 kW
Ta da... hope it's centered enough! hopefully making 25-35mm spacer this week.. if it is off enough to notice then I now have my excuse to make a custom cover!
Now that I know the exact stator measurement I will put the motor back together and test to see if everything is okay mechanically by riding it... I will also get base data on motor temperatures (with now arctic alumina- applied thermistors) before I install aluminum inserts. In the mean time I can ride my bike again!
I might go ahead and install 8AWG actually. the .375" hose does not seem feasible even with the original phase wires.. .31" may work.. But doesn't it not matter so much as long as I get a powerful pump?
Now that I know the exact stator measurement I will put the motor back together and test to see if everything is okay mechanically by riding it... I will also get base data on motor temperatures (with now arctic alumina- applied thermistors) before I install aluminum inserts. In the mean time I can ride my bike again!
I might go ahead and install 8AWG actually. the .375" hose does not seem feasible even with the original phase wires.. .31" may work.. But doesn't it not matter so much as long as I get a powerful pump?
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hillzofvalp
100 kW
Made the bushing today... Finishing touches tomorrow. I Hopefully will have the motor reassembled by the weekend. With the stator milled, I have a measurement of the stator within .0002" I'd say, so I can proceed with the machining of the cooling rings (4 halves). In the mean time I can collect some data on the non cooled motor and obtain all the components for the cooling system.
so many views on my pictures and not much feedback.. you guys are creeping me out
so many views on my pictures and not much feedback.. you guys are creeping me out
voicecoils
1 MW
you need to put 'cromotor' in the thread title! that will draw some hits.
looks like you're well on your way to a great project.
have you been having problems with the cromotor overheating or what is the inspiration for all the extra work?
looks like you're well on your way to a great project.
have you been having problems with the cromotor overheating or what is the inspiration for all the extra work?
bigmoose
1 MW
If you make your axle with the capability to circulate, before you go to all the time, expense and weight of adding the water channels; I would sure like to see you just circulate the Dextron. I'll bet you will achieve all the cooling and performance you desire with a single fluid coolant.
hillzofvalp
100 kW
I want to put this on a 150lb motorcycle and haul ass...needs to stay under 90C for consistency. Possibly putting 15-20kW through this sucker.
I don't know.. Circulating water in Chanel's (with ethylene glycol mix) would be the first thing to try. It isn't hard to dry it out and circulate oil. I don't think I have the capabilities to design a trouble-free oil reservoir within the motor and not suck up air and get consistent flow. I rather leave the messy oil inside the motor and have it transfer to aluminum coloring channels..
And as far as a 100% flooded oil motor goes.. it doesn't seem like it would be effective without custom covers that are optimized for the surface area requirements and fluid mechanics of the specific oil. I'm running this motor at very high power and do not think Oil OR Air alone would be safe trying to work with the stock covers and design. Making new covers is a whole different project I guess... not something I have time to perfect (getting perfect dimensions, figuring out clearances, etc.)
I don't know.. Circulating water in Chanel's (with ethylene glycol mix) would be the first thing to try. It isn't hard to dry it out and circulate oil. I don't think I have the capabilities to design a trouble-free oil reservoir within the motor and not suck up air and get consistent flow. I rather leave the messy oil inside the motor and have it transfer to aluminum coloring channels..
And as far as a 100% flooded oil motor goes.. it doesn't seem like it would be effective without custom covers that are optimized for the surface area requirements and fluid mechanics of the specific oil. I'm running this motor at very high power and do not think Oil OR Air alone would be safe trying to work with the stock covers and design. Making new covers is a whole different project I guess... not something I have time to perfect (getting perfect dimensions, figuring out clearances, etc.)
hillzofvalp
100 kW
I got the spacer complete today. Pics in a little bit. One little adjustment to the the location of the set screw and it will close completely... But looking good. the set screw just keeps the ring from rotating about the shaft and strangling the harness. It doesn't exert much pressure.. just a little loctite and a light fit into the dimple I made with a drill.
Added a thermistor to the milled area of stator near middle. (with arctic alumina). I hope to get a set test route and log how the temps between inner stator steel and copper winding vary. Every second or so.
Added a thermistor to the milled area of stator near middle. (with arctic alumina). I hope to get a set test route and log how the temps between inner stator steel and copper winding vary. Every second or so.
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hillzofvalp
100 kW
Good news is it still works. Motor seems torquier.. idk what's up. maybe slower top end too.. Here's an initiate temperature log test I did today. I think one of the thermistors is bad so I shifted the bad one 10 degrees lower (the stator ID).
I will change the logger so I can get a full 700Wh run in.
I will change the logger so I can get a full 700Wh run in.
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Sancho's Horse
1 kW
Nice. Putting it out there, always brass pair. Can't wait to see performance characteristics.
If it were me shaving that 150 lbs would defineately be on my list. Cheap by comparison.
If it were me shaving that 150 lbs would defineately be on my list. Cheap by comparison.
hillzofvalp
100 kW
I find it bizarre. the last couple minutes above was all down hill at around 25-35mph.. last 30 seconds was regen braking. (1000W) hmm... why the increase in temperature?
Btw, 150 lbs is AFTER weight has been shaven. It's an estimate.. but I don't really have the whole bike together to know. original bike was 190-220lbs... battery pack is 60lbs.. you do the math. I have thought about having two identical 30lb packs I could swap ... but the ability to carry both for long trips.
Btw, 150 lbs is AFTER weight has been shaven. It's an estimate.. but I don't really have the whole bike together to know. original bike was 190-220lbs... battery pack is 60lbs.. you do the math. I have thought about having two identical 30lb packs I could swap ... but the ability to carry both for long trips.
hillzofvalp
100 kW
bigmoose said:
I have so far reduced some weight from the motor. I took off the disk adapter.. Milled the covers.. The stator... Etc. the aluminum inserts, water, hoses, radiator and pump I estimate to be 4-8lbs... 1L water is 2.2lbs... I think I can compensate elsewhere as this isn't a bicycle.
I think this will be a good test. I thinks that ultimately it is more tuneable and more appropriate.. It's not a 50cc engine with tons of surface area, fins, and a proven method of agitating the oil inside. I hope to see.. It's good fun for me to make this modification.
I would like to do water cooling to a stock motor the right way and get before and after data to see what is really happening. I don't think anyone has offered such information on ES...
Edit:
I was curious just how much more the motor will weigh. Here is the weight of the cooling channels plus 50/50 ethylene glycol/water solution in the cooling channels plus 8 feet of hose and its fluid.
99.85 grams ethylene glycol (89.7 cm^3)
89.31 grams Water at 30C (89.7 cm^3)
520 grams Al Channels on each side (192.4 cm^3)
95.57 grams PTFE tubing 5/16x1/4"x8' (43.44 cm^3)
3.22 grams water (3.1275 cm^3)
3.58 grams ethylene glycol (3.1275 cm^3)
811.53 grams, 1.789 lbs. add a little bit for 24 cap head screws.. And fittings.. Subtract a bit for milling stator etc. Radiator and pump I'm estimating are 2-3 lbs total. Say 500 cm^3 in radiator adds another 500 grams.. 1.1 lb. So 4-6 lbs total.
Dextron at 500cm^3 is about 422 grams, .93 lbs. this is a bigger hub.. It may need more than the typical to achieve good thermal transfer. Bigmoose did you mean to circulate the dextron to the radiator? That would be close to the same weight.
Sancho's Horse
1 kW
If you want to get an idea of the weight, using deer hunting scales can give you a pretty good idea, and if you calibrate against an accurate scale, they work pretty well. Cheaptoo, maybe $15-20 usd.
