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[dean mcneil]

What  oil is spec for internal cooling for electric motors,  and can you use it in the liquid cooling jacket.. Would it be possible to plumb the interior and jacks with one liquid?

[Nuts n Volts]

Just some input from info that I've gathered.  I use an 75-7 motor in my R6 conversion.

-Filling half the interior of the motor with ATF or transformer oil helps greatly with cooling the SPM motor
-To my best knowledge the SPM 75-7 uses 120degC rated mags and the SPM 75-7R uses 150degC rated mags
-The SPM motor RPM is limited by the mags (lifting at higher rpms) and processor speed in the Sevcons
-The IPM motor should be able to spin faster on the same voltage with an upgraded Sevcon (Im sure they're working on this)

Related directly to the topic on hand.  Farfle (user on here and over on ES) created and arduino controlled spray cooling system for the outrunner motor he build.  Seemed to work ok, but the water spray started to get on his rear tire and caused him to crash at a track day.  Care would need to be down to protect the rear tire from getting overspray or excess water dripping on it. I do think it is a good idea, but my motor case hasn't gotten hot enough for this to work effectively.

edit: 75-7 can have 130degC mags, would have to be 120degC based on standard mags available. 

[dean mcneil]

I could cool the jacket first.  Then. Spray the interior and have it drain in a sump  to be circulated by the cooling pump.  Dry sump system?

[dean mcneil]

Could you use ec6 or fluid xp? they are nonconductive , and could be circulated thru jackets and motor internal?

[dean mcneil]

You could pump from motor, dry sump, then radiator, cooling jackets, then spray internal. That would cool rotor and both sides of stator. These liquids do not absorb heat as well as plain water but if they can be sprayed directly on internals , a considerable amount of heat should be captured.   

[MostlyBonkers]

Really useful info there Nuts, thanks. I hadn't thought about water getting on the rear tyre... D'oh!

I wonder how much drag is caused by having ATF in the motor? I'm not trying to be negative, it's just a thought. I also wonder if introducing a fluid inside the motor reduces the magnetic field somehow.

Dean: I can't help wondering if you're at risk of over-engineering a solution to a problem that will go away by swapping the motor out with an IPM model when available. However, since cost and time are going to be big factors, then the ATF solution sounds like a no brainer to me. Especially since you've already got a cooling jacket solution in place. In fact, I would say that half-filling your motor with ATF is essential to stop the rotor overheating. Just going back to the point made about the thermistor living in the stator.

Whatever you decide to do, I reckon you've got a long queue of people that would love to have a go in your kart! [emoji4]

[Lipo423]

Just some input from info that I've gathered.  I use an 75-7 motor in my R6 conversion.

-Filling half the interior of the motor with ATF or transformer oil helps greatly with cooling the SPM motor
-To my best knowledge the SPM 75-7 uses 130degC rated mags and the SPM 75-7R uses 150degC rated mags
-The SPM motor RPM is limited by the mags (lifting at higher rpms) and processor speed in the Sevcons
-The IPM motor should be able to spin faster on the same voltage with an upgraded Sevcon (Im sure they're working on this)

Related directly to the topic on hand.  Farfle (user on here and over on ES) created and arduino controlled spray cooling system for the outrunner motor he build.  Seemed to work ok, but the water spray started to get on his rear tire and caused him to crash at a track day.  Care would need to be down to protect the rear tire from getting overspray or excess water dripping on it. I do think it is a good idea, but my motor case hasn't gotten hot enough for this to work effectively.

This is good information, thanks…I believe at this point we all understand why the Temp indicator has a "built in error/margin" as 130c is not much, and we know what happens when you exceed the magnet operating temperature…not sure why Zero did not use the 150c -or higher- first place as far as I know there are commercially available 200c neodymium magnets...
It is concerning in countries like Spain, where temperatures can go pretty high why they did not include those 150c first place…anyway, shame on the engineering department (another manufacturer that designs locally and sells worldwide) 

If any of you are interested in further information about magnets temp challenges take a look at this site:
https://www.kjmagnetics.com/blog.asp?p=temperature-and-neodymium-magnets

[Nuts n Volts]

Lipo423, 

I think you need to learn more abou available magnets. Higher temperature magnets become more expensive for the same strength and they also have a lower maximum strength available.  I do not know the grade of magnet in the motors, but it is probably not possible to go to a mag greater than 150degC without having a lower strength. This means both lower torque output and lower efficiency at full current.

Additionally realize that the system as a whole should be balanced.  Zero realized that the motor was the bottleneck thermally and has made changes to fix that with the SR motor, etc.  Make the motor too good and you start overheating your controller and battery. So you might pay more for better magnets, but not get better performance because you've reached the limit on something else.

Realize with the IPM motor, Zero can use lower strength magnets and stil get the same torque output. This means they either save money on the magnets or they can go to even higher temperature magnets if they want.  My guess is they saved money due to the lower losses and better thermal performance of the IPM motor.


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[trikester]

Ah, yes: "A chain is only as strong as its weakest link".

Trikester

[Lipo423]

Lipo423, 

I think you need to learn more abou available magnets. Higher temperature magnets become more expensive for the same strength and they also have a lower maximum strength available.  I do not know the grade of magnet in the motors, but it is probably not possible to go to a mag greater than 150degC without having a lower strength. This means both lower torque output and lower efficiency at full current.

Additionally realize that the system as a whole should be balanced.  Zero realized that the motor was the bottleneck thermally and has made changes to fix that with the SR motor, etc.  Make the motor too good and you start overheating your controller and battery. So you might pay more for better magnets, but not get better performance because you've reached the limit on something else.

Realize with the IPM motor, Zero can use lower strength magnets and stil get the same torque output. This means they either save money on the magnets or they can go to even higher temperature magnets if they want.  My guess is they saved money due to the lower losses and better thermal performance of the IPM motor.


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I definitely need to learn more about magnets, no question…my level of expertise goes more in electronics/control and batteries. That being said I would appreciate you help, as it looks like you know more than me.

-How many magnets does the motor have?
- What is the type? (N30, 40, 45, etc…)

Also, if you check the link below you will notice the level of strength in the high temp magnets is very similar to the lower temp ones…(in grade 30-45, I really doubt Zero is using higher grade than that)
https://www.kjmagnetics.com/specs.asp

Concerning the controller and battery, I would agree -conceptually- with your statement (it is obvious), but I would disagree that this is the reason as I'm familiar with the Sevcom controller operation as well as the batteries.

The weaker link -today- is the motor my friend

Looking forward for the magnet-related info...

[Nuts n Volts]

I definitely need to learn more about magnets, no question…my level of expertise goes more in electronics/control and batteries. That being said I would appreciate you help, as it looks like you know more than me.

-How many magnets does the motor have?
- What is the type? (N30, 40, 45, etc…)

I dont believe I know more than you.  Unfortunately, I do not know the answer to either of these questions.  Specifics was the point I was trying to illustrate.  You said "shame on the engineering dept" without considering any other logic to they're decision.  I didnt think that was fair or that you had all the information.  Clearly you understand the information which is good.  Yes the very first model year with a brand new motor did overheat and now only three years later they have a new motor that should fix that.  All in all I think it is good engineering work.

Also, if you check the link below you will notice the level of strength in the high temp magnets is very similar to the lower temp ones…(in grade 30-45, I really doubt Zero is using higher grade than that)
https://www.kjmagnetics.com/specs.asp

Yes the strength is close, but I was only pointing out for those not informed that it is not always possible to just get higher temp mags without losing strength.  Example say 75-7R motor uses 45SH (150degC).  You'd have to lose significant strength to go to 180 or 200degC magnets.

Concerning the controller and battery, I would agree -conceptually- with your statement (it is obvious), but I would disagree that this is the reason as I'm familiar with the Sevcom controller operation as well as the batteries.

The weaker link -today- is the motor my friend

Looking forward for the magnet-related info...

My point is that people should keep in mind that at some point of modifying the motor with better cooling, they will reach the thermal limits of the controller/battery.  I know of one example in which a oil filled motor was able to overheat the sevcon. 

[Lipo423]

One of the good thing about this forum is that you always find very knowledgeable people…in my case I do not get along very well when someone suggest I should know more about an specific subject with very little or none thought/background/data/information to back him/her up.

First you state that I should learn more about available magnets, while you actually know the same as well as I…
Second also mentioned cost, while you do not know the answer either (well, I agree with you high temp magnets are more expensive, but in the 130c-150c temp improvement window from what I have been told it is just probably $100 additional cost, or less), for me that is marginal in a $18,000 bike, when one of your main selling/advertised points is "High temp magnets for higher motor performance"

Third, you find unfair my comment about the engineering department…well, I have worked with a bunch of engineers in my life, and sometimes the engineering director's office is too far from the marketing one…and there you go...I still keep my statement, Zero should have perform more testing on the SR motors before being launched, and added the 150C magnets first place.

Last, but not least, concerning your last point, I fully agree on this one. We should keep in mind other's components  thermal limits, no question, although Sevcom size 4 + current battery pack are up to the job within "non-racing" use and higher temp magnets, which is the way I ride my bike in the warm Spain...

[dean mcneil]

Hum,  In my application the motor is the first to overheat, followed by the battery then the controller. I was proactive on the controller - adding a large heat sink which was inexpensive and easily installed.  The motor has been on ongoing problem, first was a fan blowing on the motor , then forced air ventilation- bilge blower,  both helped some but neither was enough to enable me to run without dry icing the motor between rounds. Not good for the motor and a pain in the ass.  Using atf in the motor , from what every says has had only limited success, some problems-it leaks everywhere and wicks out leads,  and I have not seen any detailed specs on pumps parts and coolers that are recommended. Im hoping the water cooled jackets help- Im desperate for a solution.  It may be necessary to use the atf to spread the heat and the jackets to dissipate it.  Why atf? There are specialty fluids designed for use where non conductive fluid are required. Since atf is a lubricant this seems to cause a problem. Has anyone looked into these other non conductive fluids. We really just need to absorb the heat spread it uniformly without causing damage or causing additional friction?  Lets hope the new motor HELPS with this problem. I would be extremely surprised if it eliminated the cooling problem for any application other than moderate to heavy street use.  Creating a field with 400 amps creates HEAT. The new magnets may tolerate the heat better but they dont dissipate it. Please explain where Im off the path. This doesnt seem like rocket science or is it.

[Electronpusher]

I think one of the things zero is doing is staying away from cooling of any type except for air cooling.  Including cooling means you have to keep those components up and i think they are taking the zero maintinance route.  One idea i have not seen is a rotor that has a pass thru in the center similar idea to a hubless wheel.  This would allow for aircooling of the rotor as well as the stator.  I have never seen a motor with this design, but it would be interesting from an engineering prospective.

[dean mcneil]

If the spokes were twisted like a radial fan and both end caps were vented , with filters , it would pull air in one side and out the other.