# Motor cooling ideas



## Ziggythewiz (May 16, 2010)

How does that end fan work? It looks like it's just stuck on a mostly solid exterior. Your next two are similar, compressed air will mean spraying water on the brushes, unless you do something else to get the water out, and I don't think water cooling via spray is such a great idea.

You shouldn't need more cooling than a bilge when stopped, so not sure why the idle would help, but I hear a squirrel cage is much better for cooling than a bilge, so if you're lacking in that dept maybe you should try that.


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## Yabert (Feb 7, 2010)

Hi

The thing I don't understand from the kostov rear fan is how you can add a filter to this type of fan. What happen when you run on a dusty street??

I prefer the seal cover band over the rear motor + an external blower (150-300 cfm).

Cheap blower I use:
http://www.detmarcorp.com/blowers.htm


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## Woodsmith (Jun 5, 2008)

My 11" will be cooled in the same way, an axial fan at the comm end.
http://www.cbsonline.co.uk/product/9%22_Electric_Cooling_Fan_FAN9

My motor is designed to cool that way as it originally had vents in the drive end which I replicated with my aluminium version...









...cone shaped tubular holes through the armature, drive end...









...and comm end...









...and vents at the comm end cap.









The holes through the armature seem to act like a centrifugal fan pulling air from the DE towards the CE so I will have a fan at the CE pulling the air through. The cover band over the brushes was a solid bit of tinplate with no air holes in it. I will replace it with a 'bullet proof' bit of rolled steel in case the comm explodes.

Filtration will be an issue so I will look at ways to tackle that when I get to it. I could probably fit six little filter elements in the DE holes but will need to see if there is anything 'off the shelf' that will fit in 40mm holes.


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## Guest (Oct 18, 2011)

At rest you still want to get rid of heat if you can. What you want is a high volume fan, squirrel cage or what ever you can do. I like Jack Rickards Turbo blower. Electric motor on a turbo to blow air. Good volume there. Put on a ring around the brushes and blow the air in there. The problem with the Kostov is that the end of the motor is open to allow air flow. The fan for a kostov is actually external from the case so the end of the case is open. If you put on a ring with blower access hole like used on the warp motors you still need to find a way to close up the end. A big end fan like is shown should work just fine. One of the Kostov motors I have had a blower installed and the original fan removed. The fan works great. Lots of air is moved.


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## Woodsmith (Jun 5, 2008)

I like the idea of using an old turbo for that polished aluminium scroll that is so recognisable by petrolheads.
I was looking for one a little while ago but couldn't find one I liked, could use and would spend the money on. 
Still looking but the axial fan might be the good fall back.

Anyone who is thinking of using an axial fan on the CE will need to make sure that the fan cowling is well sealed to the motor frame to ensure that it is working efficiently and that the air moved actually goes through the motor and not spill out around the edges.


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## Yabert (Feb 7, 2010)

Hey Wood

Do you verified the flow direction of the fan? 
If it's like the Kostov forced air cooling, I don't understand your filtering systems.


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## Woodsmith (Jun 5, 2008)

Yabert said:


> Hey Wood
> 
> Do you verified the flow direction of the fan?
> If it's like the Kostov forced air cooling, I don't understand your filtering systems.


Hi Yabert,

When I first ran the motor with the aluminium DE cap on I expected the air flow to be from the comm to the drive end. Using a bit of tissue I found that the air flowed from the drive end to the comm end, it sucked the tissue into the holes.
The motor doesn't have an internal fan.

I will mount a fan at the comm end to suck air out of the motor and then look for something I can make 40mm round filters that can clip into the holes in the drive end.
The fan will be a radiator fan that mounts behind the radiator so it sucks and can cope with the heat.

My main concern is that the motor will be very close to the road and there will be an oily chain right next to the intake holes.


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## gor (Nov 25, 2009)

kostov + some cool (ing) ideas

cooloing kits
http://www.evsource.com/tls_motor_accessories.php


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## gor (Nov 25, 2009)

oil filter coolers- but you've got the idea ...


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## gor (Nov 25, 2009)

*RIPPERTON Electric track bike *
http://www.diyelectriccar.com/forums/showthread.php/ripperton-electric-track-bike-41173p38.html


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## DavidDymaxion (Dec 1, 2008)

Ziggythewiz, Yabert, Woodsmith, gottdi, and gor: Many thanks for the great information and pics!

I realize I was pretty brief in my descriptions and will add a bit more detail:

I have one of these fans blowing into a brush hole:








It is from EV Source and is rated for 148 cfm. I measured it to pull just under 4 Amps.

My motor also has the stock Kostov fan on the drive end. It blows air out of the holes radially.

Something different about my motor is it is a sepex. This means at low rpm the fields can be worked pretty hard. At 1600 rpm (idle speed with my simple homemade controller, no 0 rpm stuff there) the fields could handle 48 A, motor ran many hours and miles this way. The motor only had the internal fan. Conclusion: at 1600 rpm and 48A on the field the internal fan could keep the fields cool enough.

Then I installed a Kelly Sepex controller, 144V and 1000A nominal (BTW I like the Kelly so far, more to report on that in the future). It wants to always power the field, even sitting at 0 rpm. With 0 rpm, and 38 A on the field, the fields started smoking after about 10 minutes. This was despite the EV Source fan pictured above. Conclusion: The squirrel cage fan does not cool nearly as well as the stock internal fan does at 1600 rpm. (BTW it is a square law, heat = I^2R, so the fields had (38 / 48)^2 = 62% of the heat, but the squirrel cage still wasn't up to that. 

I lowered the field current to about 24 A, and the fields have been cucumber cool since then, even with just the squirrel cage fan blowing.

I did multiple tests at 1000A, the car was accelerating and running great and the motor case was barely getting warm. This was using both the squirrel cage fan and the internal fan.

Then I did an extended "test" at 1000A (running on the Salt Flats) and cooked my brushes. It appears overheating did them in, but it is also possible there was arcing or a lifted comm bar -- I'll be able to see better once I get it apart.

So clearly I need more cooling air on those brushes. More cooling air in general would have the secondary benefit that I could run the fields harder, for better acceleration and more regen, hence my post seeking advice on cooling.

I was very surprised to see the squirrel cage rated at only 148 cfm, but these radiator style fans rated much higher (500 to 2000 cfm!):

http://www.cbsonline.co.uk/product/9"_Electric_Cooling_Fan_FAN9

http://www.amazon.com/High-Performance-Electric-Radiator-Cooling/dp/B0038Z6LTI

It seems just a simple minded look at the CFM numbers would say a radiator style fan on the end of the motor is far superior to a squirrel cage fan. However, fans can deliver energy as air speed or pressure. An extreme example is an air compressor -- most of the energy is pressure and not from air movement. So which kind is better?

So I think I have come up with an idea. Once the motor is out of the car, I could try both kinds of electric fans -- squirrel cage and radiator style, and seeing which one blows more air through the motor.

I have thought about putting fins on the motor case, but it seems my more immediate problem is the brushes.

Side note: I hooked the squirrel cage fan to the inside of the rear bumper (it is a rear engined car). It doesn't vibrate much, but the little bit of vibration resonates throughout the whole car and is significantly louder than the motor itself! Next I'll rubber mount things, or a radiator fan to the back of the motor will leverage the motor mounts for isolation.

I've heard the new Kostovs and have seen the Warp 11 have bigger brushes than my motor has. I assume that would help keep things cooler?


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## gor (Nov 25, 2009)

yeaa - 500 -2000 cfm from thin propeller with little motor...
handheld leaf blower - 25cc 2-stroke 1.5hp at 5400 rpm - delivers 2-300 cfm at speed 180-215 mph at 3'' nozzle; 60cc heavy backpack blower - 600-800cfm, same airspeed

probably key - backpressure; if something blocks airflow (in or out) - even big leaf blowers become useless - just revving and not moving (pumping) anything ... may be we need to look not at something like airpumps - between blowers and compressors

btw: http://www.hydrogenappliances.com/mantacooling.html








For 100% duty use or extreme racing applications you may wish to add a stream of compressed air at this point ->
*2 [email protected] PSI for cooling rotor in extreme high amperage situations *
*----*
p.s. 50 psi ??? ...


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## Guest (Oct 19, 2011)

You need to move lots of air. Some things can move air with lots of pressure but little volume. Good volume is what is needed to flow cleanly through the motor. Radiator fan works for the Kostov 11". Jack Rickards works well for the Warp with the collar over the brushes and the motor driven turbo. That will move lots of air through a small opening with good pressure to get through that small opening. The Kostov has an open end so does not need the high pressure turbo style. Which by the way would beat out any squirrel cage blower for volume. In the end it is volume that is needed.


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## gor (Nov 25, 2009)

vents - little holes, small anough to not affect flux in casing - would it help?


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## DavidDymaxion (Dec 1, 2008)

Gor, I bow in your general direction! That is an awesome link. The leaf blower is genius in that a plug in leaf blower runs at 120V -- I could run it off pack voltage! A quick calculation shows one to be over 20 times the power consumption of my 12 V squirrel cage! The leaf blower could be augmented with ice, liquid nitrogen, or compressed air to also cool the air for further cooling for racing. As long as I'm on a roll here, I could use a gas leaf blower for even more cooling power! (Just kidding!)

Yet another "benefit" -- the loud leaf blower would let you know when things are getting hot! A controller to vary voltage to the leaf blower (or some have a 2 speed switch) would allow quieter operation most of the time, and save the leaf blower scream for when things are really hot.

Finally, the corded leaf blower is less than 1/2 the price of a 12 V squirrel cage. Another "final" thought is a kid's bounce house blower -- they are much quieter than a leaf blower, but OTOH are bigger and heavier.

When my motor is out, I'm planning to do a test. I'll put a huge plastic bag on the end with the exhaust holes. I'll time how long it takes to fill for 12 V squirrel cage, 120 V leaf blower, and compressed air. Additionally I'll try it with motor stopped and turning, and measure the temperature differences between compressed air and the blowers.



gor said:


> yeaa - 500 -2000 cfm from thin propeller with little motor...
> handheld leaf blower - 25cc 2-stroke 1.5hp at 5400 rpm - delivers 2-300 cfm at speed 180-215 mph at 3'' nozzle; 60cc heavy backpack blower - 600-800cfm, same airspeed
> 
> probably key - backpressure; if something blocks airflow (in or out) - even big leaf blowers become useless - just revving and not moving (pumping) anything ... may be we need to look not at something like airpumps - between blowers and compressors
> ...


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## Salty9 (Jul 13, 2009)

Has anyone checked the effect of inerting the commutator with nitrogen under heavy load? I would expect it to lessen ozone formation and dust or grease fires.


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## piotrsko (Dec 9, 2007)

Dave: on my Kostov, they have placed thermistors on a brush holder, possibly in response to the overheating issue. There is one snap switch in the field coils also. I seem to have a new style as it came with the thermistors and a rpm sensor that few knew about.


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## DavidDymaxion (Dec 1, 2008)

Thanks, that's good to know. I'll try to get that on my replacement brushes.


piotrsko said:


> Dave: on my Kostov, they have placed thermistors on a brush holder, possibly in response to the overheating issue. There is one snap switch in the field coils also. I seem to have a new style as it came with the thermistors and a rpm sensor that few knew about.


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## DavidDymaxion (Dec 1, 2008)

Idea from a model airplane friend of mine: Use ducted fans to cool the motor. They would be fairly cheap, could run on 12V, and the controllers would be cheap. It would sound neat to slowly rev them up. They would be horribly noisy at full tilt!


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## Jozzer (Mar 29, 2009)

A 120v leafblower will need an AC supply I would think..



piotrsko said:


> Dave: on my Kostov, they have placed thermistors on a brush holder, possibly in response to the overheating issue. There is one snap switch in the field coils also. I seem to have a new style as it came with the thermistors and a rpm sensor that few knew about.


 On mine it's the other way round, thermistor on field coils and snap switch on brush assembly..


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## DavidDymaxion (Dec 1, 2008)

A plug-in AC leaf blower likely uses a "universal" motor. It turns out you can run a "DC" series motor on AC, as a DC series motor turns the same direction for either direction on the current. This is desirable when you want to spin the motor really fast, like in a vacuum cleaner or drill. So there is a good chance the leaf blower will work on DC -- but the switches won't! I would need to use a contactor to switch it.

Interesting about the snap switches on the brushes. Is the switch on the brush itself or on the holder? Is there a case where one brush might run hot while the others are cool? It might it make sense to do a snap switch on each brush in that case. You could do them all in series (normally closed) or parallel (normally open) to see if any brush is complaining.


Jozzer said:


> A 120v leafblower will need an AC supply I would think..
> 
> 
> On mine it's the other way round, thermistor on field coils and snap switch on brush assembly..


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## Jozzer (Mar 29, 2009)

I havn't yet stripped it to see, but Plamen told me the thermistor was connected to "the brushholder".

If you were considering placing a sensor on each brush, it would be more useful to use thermistors (though, I've recorded brush tems in different motors at 450C before now, it will be tricky finding a thermistor that survives). That way, you could use it as diagnostics to check each brush is sharing its load properly. If you want to run that near the edge it would be worth checking that the resistances of all brushes are matched also...


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## Plamenator (Mar 6, 2009)

Sorry if I have somehow misled you.
Cut of temp switch is on brushholder (not on the brush itself though and there is only one switch).
Thermistor is buried in the stator coils.


In general cooling systems are of great interest to me.
I have tried the copper tube spiral too but it is of very little value.
Tried a few other arrangements as well but best results we got from the one we sell at the moment:
http://kostov-motors.com/tractionmo...toraccessories/forcedaircoolingfanfor9models/
One can easilly add some filter fabric in between the flange and the fan but it will probably reduce air flow.


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## Jozzer (Mar 29, 2009)

Hi Plamen,

So with your fan, the endplate of the motor is removed and the fan blows accross brush holders, commutator, and armature? Do you have any pics of one fitted? (FYI, the fancy "built for speed" and "forced cooling" links are dead, I seem to recal there were pics there).

Steve


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## Plamenator (Mar 6, 2009)

I will have a look at the applets tomorrow - thanks 

Actually there are holes at the back plate to allow the fan to blow air in.
Currently working on some other back plate configurations with larger holes but this is a marginal improvement only.


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## Jozzer (Mar 29, 2009)

Plamenator said:


> I will have a look at the applets tomorrow - thanks
> 
> Actually there are holes at the back plate to allow the fan to blow air in.
> Currently working on some other back plate configurations with larger holes but this is a marginal improvement only.


 You mean the 8mm holes in the endplate on the right hand motor in that pic? Yes, that could stand some improvement!
Is that endplate structural and holding the bearing? How much material could be removed? Four 25mm holes would be the minimum to make much use of the fan I would think?

Water misting the motor shell when near 100C would remove heat pretty fast, especially if assisted with a fan. Of course it wouldn't directly cool the hottest parts of the motor, but would increase the S2 power rating nonetheless IMO.
On Agni pancake motors we spray a very fine mist of distilled water onto the armature, which really sucks heat out fast, but Agni brushes are safe from spray, and the water doesn't mix with carbon OR go near the brush assembly, and also runs at a lower voltage. I havn't stripped the Kostov yet for a good look, but it seems like it would be hard to wet the armature safely in the same manner..

(Plamen runs off to find a water squirter)

Steve


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## Plamenator (Mar 6, 2009)

No, I mean the holes on the back plate on the LEFT hand motor (right hand one has no forced air cooling at all). Look carefully in between the blades of the 12V fan.

I do not think pouring water on a brushed DC (none PM) is a good idea...


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## Jozzer (Mar 29, 2009)

Ahh, I see, look like 10-15mm slots? That's more like it!
I guess it makes more sense to experiment with our endplate on the mill than to order one from you and change it, any tips on how much material is safe to remove?
Steve


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## DavidDymaxion (Dec 1, 2008)

Thanks Plamenator, this is great information.

I assume the holes are right at the brush positions? Are there 4 holes, or more? Thanks for the info. It seems like it would work better to blow in air from end, axially, rather than pushing air in radially via the brush cover holes.


Plamenator said:


> I will have a look at the applets tomorrow - thanks
> 
> Actually there are holes at the back plate to allow the fan to blow air in.
> Currently working on some other back plate configurations with larger holes but this is a marginal improvement only.


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## gor (Nov 25, 2009)

special tubing, used in cooling systems


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## gor (Nov 25, 2009)

turbo and roots-type el.superchargers
turbo: 5a12v3psi435cfm/6000rpm -9a24v6psi628cfm/12000rpm

tkt ec400 article http://www.turbomagazine.com/tech/0406tur_knight_turbo_electric_supercharger/index.html


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## Guest (Oct 26, 2011)

Jozzer said:


> Ahh, I see, look like 10-15mm slots? That's more like it!
> I guess it makes more sense to experiment with our endplate on the mill than to order one from you and change it, any tips on how much material is safe to remove?
> Steve



Go have a look at the Kostov 11" busted down. Plenty of albums of photos here for you to have a look at. Can't see that there would be much of any improvement with how open it is at this time.

Pete 

http://greenev.zapto.org/kostov


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## Jozzer (Mar 29, 2009)

Thanks, nice album. Unfortionatly, it looks like those are all pics of the older motor? Mine looks significantly different..

Steve


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## Guest (Oct 26, 2011)

Yes they are the older style. I did not know that the new ones were changed that much. Got some photos? 

Pete


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## Jozzer (Mar 29, 2009)

Well, I will have in a couple of weeks.

Perhaps Plamen will give us some more details of precise changes between old and new designs?

Steve


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## piotrsko (Dec 9, 2007)

OH CRUD!! my brush holes were tapped 5/16-18 so I used them for mounting the front motor plate. This does explain why the holes didn't match the drawing very well. and I checked, I have a thermistor on the brushes.


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## Deebs (Oct 10, 2011)

Has anyone out there experimented with a C02 cooling system? It seems like a practical way to cool things off in a hurry (such as during high amp pulls).


http://www.summitracing.com/search/Part-Type/CO2-Cooling-Systems/

Summit carries a few kits that include a bottle, solenoid, SS lines, etc..


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## Guest (Nov 2, 2011)

Cooling needs to be practical and implementable. Not some far fetched ideas. Something that uses no outside components that can run out. You surly don't want to have to constantly refill the thing to keep a motor cool. For racing maybe but not for a street machine. 

Pete


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## Deebs (Oct 10, 2011)

I totally agree Gottdi..C02 cooling would not be very practical for daily driving. I was simply trying to entertain the idea...being I have yet to see someone with such a setup. 

I could see C02 benefiting drag racers wanting to push the limits of their motors for 10-15 seconds. It would not be hard to wire the solenoid to release C02 only at the highest bursts of amps.


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## gor (Nov 25, 2009)

with airflow direction from CE to DE - brash carbon dust goes through the motor?

pict. Devolt debris ejection








btw. Dyson Root Cyclone - what exactly speed and what it takes to achieve such airflow velocity in vortex? (particles separated by "100 000 times force of gravity" centrifugal force) 
http://www.dyson.com/technology/rootcyclone.asp


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## SolarJ (Sep 12, 2009)

Has anyone sealed a brushed motor and ran a closed loop oil cooler on it?

Kinda the way a brushed high pressure fuel pump is done. The fuel flows through motor.

Thanks, Jim


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## dtbaker (Jan 5, 2008)

SolarJ said:


> Has anyone sealed a brushed motor and ran a closed loop oil cooler on it?
> 
> Kinda the way a brushed high pressure fuel pump is done. The fuel flows through motor.
> 
> Thanks, Jim



I DO remember seeing someone's build with soft copper tubing wrapped around the body of the motor and run thru a transmission cooler..... It would probably 'help', and may even be fairly effective if the cooling loops had a good thermally conductive bond with the casing.

I wouldn't seal the motor though.... that airflow thru the center is probably key to life of brushes, windings and bearings....

I've been thinking that perhaps an aluminum 'jacket' with fins could be clamped on and help dump a little more heat into the air circulating around the motor bay... but dumping heat into air is not as fast as into a liquid of course.


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## SolarJ (Sep 12, 2009)

Not what I was thinking. Actually sealing the motor and running the coolant through the internals of the motor. Like a high pressure electric fuel pump is done. It would also extinguish any arcs because there is no oxygen.


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## dtbaker (Jan 5, 2008)

SolarJ said:


> Not what I was thinking. Actually sealing the motor and running the coolant through the internals of the motor. Like a high pressure electric fuel pump is done. It would also extinguish any arcs because there is no oxygen.



OH!

well, I am sure some of the motor experts will chime in. My first response would be 'are you serious?'

Brushed DC motors are in no way designed to withstand full immersion. Even if you could solve shorting issues with a non-conductive fluid, you be adding a HUGE amount of physical resistance with the fluid in shear between the guts spinning and the casing static.


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## piotrsko (Dec 9, 2007)

Except for back emf induced brush arc, arcs are caused by some of the motor carbon migrating about the motor internals thereby reducing the insulating path resistance. AKA dielectric breakdown. Admittedly the breakdown voltage goes way up with a different cooling medium, but as DTBAKER says, so does drag.

There was a thread where someone was adapting a Mil-H-6086 immersed motor into a powerslide, but that was a year ago, and it kinda dies.


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## gor (Nov 25, 2009)

- how liquid medium would affect magnetic flux in "air gap"?
if pluses from dielectric and cooling properties of liquid medium would exceed minuses from drag ... we might have less efficient but more powerful motor

idea simple and logical extension of external cooling, but huge amount of external cooling and absence of internal - might indicate - it's not that simple...
since this comparatively easy to accomplish - should be info on somebody who tried...


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## dtbaker (Jan 5, 2008)

gor said:


> - how liquid medium would affect magnetic flux in "air gap"?
> if pluses from dielectric and cooling properties of liquid medium would exceed minuses from drag ... we might have less efficient but more powerful motor
> 
> idea simple and logical extension of external cooling, but huge amount of external cooling and absence of internal - might indicate - it's not that simple...
> since this comparatively easy to accomplish - should be info on somebody who tried...


go ahead and run a garden hose through your motor, and let us know what happens.


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## gor (Nov 25, 2009)

dtbaker said:


> go ahead and run a garden hose through your motor, and let us know what happens.


just tell us what happened when you tried - i won't lough, i promise : )))


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## aeroscott (Jan 5, 2008)

make a gaseous helium cooling system (5-10 psi) , sealed system feeding inter cooler from turbo charged and inter cooled car . this is the second most thermally conductive gas . hydrogen is the first and used by the utility's for cooling there big generators . The ones I've seen had a water cooled radiator just under the generator , boxed into the bottom generator . No idea of how the gas was pumped or circulated .


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## aeroscott (Jan 5, 2008)

air 33.3 millwatts/ meter kelvin , Hy =230.4, He=190.6 . conductivity of gases thermal .


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## gor (Nov 25, 2009)

aeroscott said:


> make a gaseous helium cooling system (5-10 psi) , sealed system feeding inter cooler from turbo charged and inter cooled car . this is the second most thermally conductive gas . hydrogen is the first and used by the utility's for cooling there big generators . The ones I've seen had a water cooled radiator just under the generator , boxed into the bottom generator . No idea of how the gas was pumped or circulated .


hydrogen cooling for turbogenerators - big staff, probably way too expensive; any info of can it (or similar) be used on small scale? 

... just to pump some "freon" through the rotor - to freeze that sucker ... 
- if can't through the rotor - than through external jacket - and freeze the whole thing : ))))


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## gor (Nov 25, 2009)

something like kers cooling by motor oil - rotor & stator (f1honda)?


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## Snakub (Sep 8, 2008)

What about wrapping the motor in larger steel brake line then welding it to the motor in places and running coolant through it? I am thinking about experimenting with this on my go kart at first.


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## aeroscott (Jan 5, 2008)

gor said:


> hydrogen cooling for turbogenerators - big staff, probably way too expensive; any info of can it (or similar) be used on small scale?
> 
> ... just to pump some "freon" through the rotor - to freeze that sucker ...
> - if can't through the rotor - than through external jacket - and freeze the whole thing : ))))


All that is needed is a inter cooler (radiator) some tubing (2" or whatever goes with the inter cooler), a computer fan or two (they go inside the tubing ) , inclose the motor , seal the shaft and plumb the inter cooler hoses to the new motor inclosure . Now charge with helium and turn on the fan/fans . very low power consumption . Only hard part is sealing shaft ( some motors will be easy others not so) . For all this work we get 5.7 X better cooling then air , much thinner gas will get into the hot little corners better and much less wind drag for the motor .PS; helium should interfere with the brushes in a negative way.


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## aeroscott (Jan 5, 2008)

If you have water cooling , take a heater core mount it in the new motor enclosure with the fans . Advantages , less helium ,more compact, maybe cheaper and just like the big boys . You could add a air conditioner evaporator to actively cool the motor .PS; But at higher power consumption .


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## gor (Nov 25, 2009)

aeroscott said:


> All that is needed is a inter cooler (radiator) some tubing (2" or whatever goes with the inter cooler), a computer fan or two (they go inside the tubing ) , inclose the motor , seal the shaft and plumb the inter cooler hoses to the new motor inclosure . Now charge with helium and turn on the fan/fans . very low power consumption . Only hard part is sealing shaft ( some motors will be easy others not so) . For all this work we get 5.7 X better cooling then air , much thinner gas will get into the hot little corners better and much less wind drag for the motor .PS; helium should interfere with the brushes in a negative way.


Scott,can you put quick scetch(schematics) - auxilaries, what it takes, what goes whear, motor crossection, etc

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p.s. btw. there was some old patents - spraying oil for lube and rotor cooling

who have kostov's internals drawing?
.


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## gor (Nov 25, 2009)

some suggested try to run garden waterhose through the motor to see what happens, - they say - it was a stupid idea...

- that's how you do it: 
http://endless-sphere.com/forums/viewtopic.php?f=30&t=33440


> ...
> For the watercooling, I used a normal windscreen washer pump trowing a little distilled water through the holes in the circumference of the motor to spray on the outer edge of the armature just to show how effective it could be. Obviously there is a great deal of potential here to increase continuous power rating significantly.
> I do have (and have used at the track) a proper temperature controlled high pressure pump and very fine misting jet that produces far better results, but have yet to find time to hook it all up to the dyno and tune it. When I do, I'll add results here..


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## aeroscott (Jan 5, 2008)

gor said:


> Scott,can you put quick scetch(schematics) - auxilaries, what it takes, what goes whear, motor crossection, etc
> 
> ----------
> p.s. btw. there was some old patents - spraying oil for lube and rotor cooling
> ...


"A picture is worth a thousand words " I haven't done any auto cad in a long time . I could draw a picture , scan it and down load . I'll try that later today .


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## JohnMartyn (Nov 15, 2011)

This heating effect of the heat-sink getting hot is the evidence you need to see that your motor's insides are being cooled by it.Adding antifreeze to water will protect against boiling and/or freezing, but reduces the water's ability to carry or transport heat to the radiator big time.


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## aeroscott (Jan 5, 2008)

In court today ,Oh great fun . have to work on this fight with the city/port.


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## iti_uk (Oct 24, 2011)

JohnMartyn said:


> This heating effect of the heat-sink getting hot is the evidence you need to see that your motor's insides are being cooled by it.Adding antifreeze to water will protect against boiling and/or freezing, but reduces the water's ability to carry or transport heat to the radiator big time.


The lowered thermal capacity is, however, offset by the "wettening" of the water provided by (most) anti-freeze (the break-down of the surface tension of water, allowing better and more consistant contact with the heat exhanger surfaces), not to mention corrosion protection. Very important when considering a cooling system.

Pumping freon will do nothing earth-shatteringly great unless you include a choke in the flow to provide high- and low-pressure halves of the system (the high-pressure being around the motor, the low pressure being around the radiator/cooler), just like any proper A/C system.

A good water-cooling system surely should be more than adequate for automotive use? When designing it, just try to remove air gaps and you should be okay...

Chris


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## ElectriCar (Jun 15, 2008)

Awful lot of overly complicated ideas here and why? Is there something wrong with a simple solution like ducting a blower to the motor with an air filter on the intake like someone posted a photo of here? I'd like to do that with a 12V blower of some type with a temperature based speed controller.


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## ElectriCar (Jun 15, 2008)

Here's a PID temperature controller that will work if this unit has a 0-10V output. It can be used to signal this motor controller to vary the speed of a 12V blower.


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## DavidDymaxion (Dec 1, 2008)

I had stated it in another thread. My motor overheated doing a Salt Flats run. I did exactly as you describe, on top of the internal cooling fan, and that wasn't enough. So I started this thread looking for better ideas -- and I did get some great ideas! I didn't get even one "why don't you just slow down" suggestion!


ElectriCar said:


> Awful lot of overly complicated ideas here and why? Is there something wrong with a simple solution like ducting a blower to the motor with an air filter on the intake like someone posted a photo of here? I'd like to do that with a 12V blower of some type with a temperature based speed controller.


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## ElectriCar (Jun 15, 2008)

Oh ok. I'm just looking for cooling for normal driving so as to not have to keep the motor reved up above 3000 rpm.


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## Scuderia Elettrica (Sep 10, 2011)

This is sort of off topic but so many high performance builds have motor cooling problems and this has got me thinking about reducing general operating temperatures... some places offer controller cooling kits however is it worth it to add a controller cooling kit to further reduce operating temperatures or is the benefit minimal enough to ignore


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## Plamenator (Mar 6, 2009)

ElectriCar said:


> Oh ok. I'm just looking for cooling for normal driving so as to not have to keep the motor reved up above 3000 rpm.


Actually keeping the motor in 3000-4500rpm is quite beneficial - you get both better cooling and higher gear ratio the latter ensuring lower amp draw.

In my opinion there is very little point in adding water cooling to a good controller. Usually the problem is the motor so dollars spent on improved motor cooling are a better investment (when motor temperature starts being a problem, controller can be quite cool). That said, cooling the motor is often much more difficult as this thread shows.


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## Scuderia Elettrica (Sep 10, 2011)

It would be interesting to find a good write up on the EV car that goes up Pike's Peak every year... it would be interesting to see how they deal with the cooling problems but can manage such highly competitive times in such thin air and up such a steep incline 

Also how would this do for a liquid coolant, seems like it could be beneficial to higher performance builds if combined with the earlier stainless steel lines wrapped around the motor perhaps some substantial improvements could be found 
http://www.evanscooling.com/products/coolants/


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## notailpipe (May 25, 2010)

DavidDymaxion said:


> YARI (Yet another random idea): What about spraying distilled water at the brushes?


Okay, I'll admit I don't know much about how motors work except that the brushes make the electrical connections work every 180 degrees of rotation.

But WHAT AM I MISSING? Why on earth would you spray water over the brushes???  Won't that short out all the electrical paths inside the motor? I am sitting here wondering if my car can handle road mist/snow slush splashing up into the motor or if I need a protective underbody belly pan... and here people are spraying water through their motors intentionally!

Someone please give me the 101 on this, I'd be greatly appreciative. I don't want to derail what looks like a productive thread, so if you want to PM me instead of replying that would be perfect.

Thanks


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## rochesterricer (Jan 5, 2011)

I actually think such a discussion would be relevant to this thread


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## DavidDymaxion (Dec 1, 2008)

Water is not as bad as it sounds. Electric boat racers would regularly get their motors wet, including full immersion. One EVer reported dumping a hose right into the motor, while it was turning, to clean it (not that I'd recommend doing that!). The copper and brushes are far more conductive than water, so the current will not want to go through the water. Some over-clockers run computer fans immersed in oil Having said all that, it was a question, could water spray or mist be an effective way to cool things?

Also note it was "distilled water." I would not want road grime, rocks, sand, salty water, etc. getting splashed into the motor! A belly pan to protect the motor is a great idea.




notailpipe said:


> Okay, I'll admit I don't know much about how motors work except that the brushes make the electrical connections work every 180 degrees of rotation.
> 
> But WHAT AM I MISSING? Why on earth would you spray water over the brushes???  Won't that short out all the electrical paths inside the motor? I am sitting here wondering if my car can handle road mist/snow slush splashing up into the motor or if I need a protective underbody belly pan... and here people are spraying water through their motors intentionally!
> 
> ...


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## cruisin (Jun 3, 2009)

DavidDymaxion said:


> Water is not as bad as it sounds. Electric boat racers would regularly get their motors wet, including full immersion. One EVer reported dumping a hose right into the motor, while it was turning, to clean it (not that I'd recommend doing that!). The copper and brushes are far more conductive than water, so the current will not want to go through the water. Some over-clockers run computer fans immersed in oil Having said all that, it was a question, could water spray or mist be an effective way to cool things?
> 
> Also note it was "distilled water." I would not want road grime, rocks, sand, salty water, etc. getting splashed into the motor! A belly pan to protect the motor is a great idea.


 
With AC, like all production cars use, and the AC-50 used in conversions the motor does not get too hot as the heat is generated on the outside of the case. Dc creats all the heat in the center of the motor creating the need for cooling.


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## notailpipe (May 25, 2010)

So if you wanted a passive cooling technique, could you just leave a rectangle cutout in the underbelly plastic and put like a screen-door screen there to keep out rocks? Maybe time to time take the garden hose and spray out the motor brush housing?

What would happen in most street-EVs if you just covered the bottom and relied totally on the build-in impeller/fan to cool the motor? I heard one guy say that made his really hot but it was sortof anecdotal.

Thanks.


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## DavidDymaxion (Dec 1, 2008)

AC does run cooler, although the GM EV-1 did liquid cool its motor.

Exception that proves the rule : My DC sepex motor can and does make the case hot while the armature is cool (unlike the ubiquitous series DC).


cruisin said:


> With AC, like all production cars use, and the AC-50 used in conversions the motor does not get too hot as the heat is generated on the outside of the case. Dc creats all the heat in the center of the motor creating the need for cooling.


It's probably much better to keep the rocks and grit out of the motor in the first place, rather than hose it out.

Obviously if you do "too good" a job of sealing the motor compartment you'll recirculate the air, and it'll get hotter and hotter. You'd want fresh, cool air into the motor, or exhaust the hot air outside.

I didn't notice a belly pan under the motor made it hot, but I have huge gaps everywhere plus a grill. A mechanic and fellow EVer suggested I copy what Porsche did, and seal the motor compartment like Porsche did with the gas car. Fresh air goes into the upper part of the motor compartment, and hot air gets exhausted below.


notailpipe said:


> So if you wanted a passive cooling technique, could you just leave a rectangle cutout in the underbelly plastic and put like a screen-door screen there to keep out rocks? Maybe time to time take the garden hose and spray out the motor brush housing?
> 
> What would happen in most street-EVs if you just covered the bottom and relied totally on the build-in impeller/fan to cool the motor? I heard one guy say that made his really hot but it was sortof anecdotal.
> 
> Thanks.


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## ElectriCar (Jun 15, 2008)

Water is a poor conductor relative to copper. However for anyone to think it's a good idea to hose your commutator I can't help but think you've lost it. You're spraying water into the bearings which if not sealed will rust once you shut it down and eventually need replacing.

Water also will conduct. At 72V not so much but at 165 like I run, it's much more likely to cause a problem. I have no idea other bearing issues that you might encounter but if the voltage is high enough it may create some carbon tracking issues as well or it may not. 

However whichever one of you brave souls tries it, and I'm sure someone will,  please post photos of the results with your voltage specs.


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## iti_uk (Oct 24, 2011)

I wonder whether the H and the O in water (especially if sprayed as a mist) would split due to electrolysis at the voltages EV motors run at. If it did, I wonder how much of an explosion you'd get when the comm arcs and the H and the O react to form water...

This would require a major redesign of the motor, but how about a through-shaft liquid cooling system? Hollow amrature shaft with radial outlets along its length feeding channels cut into the iron laminate, returning to the shaft and being fed through a concentric inner pipe back down the shaft's length. The seals on this system would have no harder task than the output seal on a gearbox. The drawbacks would be the requirement of a large diameter shaft, possible torsional weakening of the shaft due to the radial channels, and cost of machining.

I've attached a quick brain-fart of what I'm trying to describe. MS Paint FTW! 

Chris

Brain fart update: Alternatively, reverse the flow path as I have drawn it in the diagram, so that "coolant in" passes down the centre of the bore. (Now shown in the second picture) Attach a larger diameter boss (the black part, which would have fins internally, a-la-impellor) to rotate with the armature. This could provide passive coolant flow and could drain into a loose-fitting coolant collector, removing the requirement for one of the two seals on the shaft, this reducing rotational friction.


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## DavidDymaxion (Dec 1, 2008)

Good question, but I think the risk is minimal. Lots of EVs have motors open to the outside world and survive an occasional splash just fine. Again, I wouldn't suggest this! It's better to protect your motor.

I'm going to try more air flow for keeping my brushes cool enough... but I might try a bit of water spray if that doesn't do it. It would be distilled water, and a gentle spray, not a flood. If I do that I'll report the results, good or bad.

Here are some fun numbers for conductivity from http://en.wikipedia.org/wiki/Electrical_resistivity_and_conductivity : 

Copper 2e-8
Carbon 2e-6
Sea Water 2e-1
Deionized Water 2e5

Even sea water is 100,000 times more resistive than carbon and 10,000,000 more resistive than copper. Electricity is going to greatly prefer flowing through the carbon brushes and copper of a motor over water.


iti_uk said:


> I wonder whether the H and the O in water (especially if sprayed as a mist) would split due to electrolysis at the voltages EV motors run at. If it did, I wonder how much of an explosion you'd get when the comm arcs and the H and the O react to form water...
> 
> This would require a major redesign of the motor, but how about a through-shaft liquid cooling system? Hollow amrature shaft with radial outlets along its length feeding channels cut into the iron laminate, returning to the shaft and being fed through a concentric inner pipe back down the shaft's length. The seals on this system would have no harder task than the output seal on a gearbox. The drawbacks would be the requirement of a large diameter shaft, possible torsional weakening of the shaft due to the radial channels, and cost of machining.
> 
> ...


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## MalcolmB (Jun 10, 2008)

Just as a datum point: I've been running in a pair of 7" motors for my Mini on the bench over the weekend. I ran them at 12V and they draw about 30A each with no load.

At first I ran them without any cooling. After half an hour or so the motor casings had reached around 55C. I then hooked up a single 12V fan to the brush covers on both motors using 3" ducting. I used a squirrel fan – an AC blower from a Range Rover. It pulls about 4.5A at 12V. After 3 hours continuous running the motors were still only lukewarm. One curious thing I noticed is that within a minute of switching on the fan, the motor current rises by about 1.5A. Not sure why. Could it be an increase in drag in the narrow gap around the armature, or an increase in friction between the brushes and commutator?


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## RobSmith (Aug 13, 2010)

SolarJ said:


> Not what I was thinking. Actually sealing the motor and running the coolant through the internals of the motor. Like a high pressure electric fuel pump is done. It would also extinguish any arcs because there is no oxygen.


Yup.
The AC and Bosch pumps are fully submersed.
I designed the fuel systems in quite a few race cars and they have a few lift pumps and usually one or two high pressure pumps.
The fuel goes through the motors, around the windings, around the brushes etc. Keeps the motors cool and clean and lubricated.
All these pumps draw a lot of current added together, plus big lights for night use and lots of electronics so end up with 200A alternators, sometimes two of them. These are also fed cooler air from outside the bodywork. The fans on these alternators work well as they are usually running near to flat out at about 16000 rpm.

Someone mentioned using a turbo as a fan. Maybe but they spin at ludicrous speeds (something like 50 000 - 100 000 rpm) and run in oil fed non contact bearings so would need an oil feed unless you came up with a different arangement.

Rob


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## gor (Nov 25, 2009)

RobSmith said:


> Yup.
> The AC and Bosch pumps are fully submersed.
> I designed the fuel systems in quite a few race cars and they have a few lift pumps and usually one or two high pressure pumps.
> The fuel goes through the motors, around the windings, around the brushes etc. Keeps the motors cool and clean and lubricated.
> ...


 what about sparks in brushes, contacts, etc, submerged into fuel?


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## RobSmith (Aug 13, 2010)

gor said:


> what about sparks in brushes, contacts, etc, submerged into fuel?


Like the other chap said. Once submerged there is no air in there to have a fire with. The brushes are relatively very large with a big contact area so presumably they design out sources of sparks. The brushes on the AC (not alternating current. AC being the manufacturer) are flat on the end of the armature like slices of a pizza.
I might have a spare one here with a broken off terminal. If I find it I will cut it open and take some pictures.

Rob


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## gor (Nov 25, 2009)

RobSmith said:


> Like the other chap said. Once submerged there is no air in there to have a fire with. The brushes are relatively very large with a big contact area so presumably they design out sources of sparks. The brushes on the AC (not alternating current. AC being the manufacturer) are flat on the end of the armature like slices of a pizza.
> I might have a spare one here with a broken off terminal. If I find it I will cut it open and take some pictures.
> 
> Rob


Rob, take video when it sparking in gasoline...
that would be ... more than awesome ...


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## RobSmith (Aug 13, 2010)

RobSmith said:


> Like the other chap said. Once submerged there is no air in there to have a fire with. The brushes are relatively very large with a big contact area so presumably they design out sources of sparks. The brushes on the AC (not alternating current. AC being the manufacturer) are flat on the end of the armature like slices of a pizza.
> I might have a spare one here with a broken off terminal. If I find it I will cut it open and take some pictures.
> 
> Rob


I could not find the one I had / have. I might have thrown it out as it had a broken terminal.
I have found this on the internet:
http://www.volvoclub.org.uk/faq/FuelTankSenderReplacement.htm
If you scroll right to the bottom you can see the chap has cut the pump open and all those bits have fuel flowing around them.... hence the rest of the armature is spotlessly clean.

Whilst hunting around my shed I also found a fridge pump motor. Some time ago I cut open the black compressor blob to see what was inside. That motor too sits in the refrigerant and oil. (although no brushes on that).
I also found a BMW K100 motorbike fan that might make a nice fan for a 7" or 8" diameter motor.
Edit: Picture of a BMW K100 fan.... http://www.ioffer.com/img/item/144/178/57/1.jpg you can easily cut the three 'ears' off to make a round housing about 8" diameter.

Edit: Just found this.. http://www.kz1300.com/techarticles/zn1300-fuel-pump.html although it is an older pump.


Rob


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## gor (Nov 25, 2009)

iti_uk said:


> I wonder whether the H and the O in water (especially if sprayed as a mist) would split due to electrolysis at the voltages EV motors run at. If it did, I wonder how much of an explosion you'd get when the comm arcs and the H and the O react to form water...
> 
> This would require a major redesign of the motor, but how about a through-shaft liquid cooling system? Hollow amrature shaft with radial outlets along its length feeding channels cut into the iron laminate, returning to the shaft and being fed through a concentric inner pipe back down the shaft's length. The seals on this system would have no harder task than the output seal on a gearbox. The drawbacks would be the requirement of a large diameter shaft, possible torsional weakening of the shaft due to the radial channels, and cost of machining.
> 
> ...


or like this:


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## ElectriCar (Jun 15, 2008)

gor said:


> what about sparks in brushes, contacts, etc, submerged into fuel?


 For a fire you have to have three components, fuel, heat and oxygen. Remove either and you have no fire. So in a fuel system you do have two but you'll never have a fire with no oxygen present.


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## gor (Nov 25, 2009)

ElectriCar said:


> For a fire you have to have three components, fuel, heat and oxygen. Remove either and you have no fire. So in a fuel system you do have two but you'll never have a fire with no oxygen present.


i know, i know....
... so, also to do not worry about some imperfections - air bubbles, air pockets, run out of fuel, air leaks, etc? ...
how they deal with it?

p.s. and also what about cavitation?


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## iti_uk (Oct 24, 2011)

gor said:


> or like this:


Having the coolant inlet on the front of the shaft would get in the way of the drive output of the motor, the only possible way around this would be to have a gear or chain drove off to one side of the armature, but even then you're left with having to drain/disassemble/assemble/re-fill the coolant system every time you need to do any work on the motor output. Keeping inlet and outlet at the rear leaves the front of the motor clear and open.

Plus you're introducing a weakening of the drive end of the armature by having a coolant channel pass through it. The rear of the armature doesn't have the same torque requirement as the front, as it is essentally unloaded torsionally, so we can be more confident about removing material here without a negative impact on the mechanical performance of the motor.

Chris


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## gor (Nov 25, 2009)

should be in this thread too - can someone comment, why such shaving, slots, etc - very bad cooling or weight saving idea: no cool, no-no for e.motor?


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## piotrsko (Dec 9, 2007)

I was under the impression from major that such modification affected the motor magnetic currents in the case, possibly in a bad way. His gist was: if it worked really well these thing would be on the motor from the factory.


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## gor (Nov 25, 2009)

piotrsko said:


> I was under the impression from major that such modification affected the motor magnetic currents in the case, possibly in a bad way. His gist was: if it worked really well these thing would be on the motor from the factory.


 true, in that extreme experimemt, motor not just lost all guts under load, but start heating even more


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