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[MostlyBonkers]

Humour me here...

You know those trigger water sprayers for plants?

Plastic Trigger Spray Bottle Plants Water Sprayer 500ML https://www.amazon.co.uk/dp/B00D12GD0A/ref=cm_sw_r_awd_R1Tswb68VBA7W

The trigger could be mounted on the left handlebar, just like a clutch lever.  The nozzle (or multiple nozzles) could be suspended over the motor and the water bottle could go in the frunk. It would be no different than the spray that hits the motor when it's raining, so it shouldn't do any harm. A few squirts to wet the fins would be a bit like blowing on a hot cup of tea. I can't help thinking it could make a difference!

This one's for you Lipo. What do you think? It could be quite fun too. You might even leave a cloud of steam trailing behind you which might turn a few heads!

Feel free to vote below:

Bonkers or worth a try? [emoji4]

[Erasmo]

I can make a napkin calculation for you but for that I will need the weight of the motor and the surface area that you plan to spray.

[MostlyBonkers]

I couldn't tell you on either count Erasmo. I don't think it's trivial to work out. However, it would be interesting to know how much heat would dissipate from a surface area of 100 cm squared at 90 degrees Celsius with 5 millilitres of water spread over it. Is that something you can work out?

[Erasmo]

I could do that later at home but the result will probably be far too high since most of the water will be blown of the motor surface before it has a change to evaporate.

[MostlyBonkers]

Very kind of you Erasmo but I think we need a practical test:

Run a motor up to max a few times and see how long it takes to cool. Then do a run, pull over, spray the motor and get back on it to see if it makes a difference. I wouldn't encourage anyone to try spraying with a squirty bottle whilst riding. You'd need a proper setup for that. If you wanted to get serious an inline electric pump would get better results, especially with multiple nozzles providing a good drenching for a couple of seconds. A button on the handlebar to activate the pump and it would feel like having DRS in formula one for overtaking! You'd also have the pleasure of dumping a cloud of steam on the cars as you pulled in front of them. [emoji1]

[grmarks]

Turbo charged cars can (and do) have water jets to spray water on intermittently the intercooler. Its just a fine mist as the act of evaporation draws heat out of the radiator. It is not saturated with water.
The  setup is a bit different as an intercooler is made of very thin material. But any water sprayed onto the motor would take out heat for sure. Just put a chunk of hot steel under the tap for a few seconds and it's cold. You could not saturate the motor as it would take a huge amount of water to cool for a long time.
A fine spray is the way to go and intermittent to let it evaporate. The question is how much water how often to lower the motor temp as much as you need.

Give it a go as it will definitely do something.
   

[NEW2elec]

What if we had water passing all around and maybe through the motor inside thin heat conducting tubes.  Then instead of having to have a big drum of water we collected the water in an area that would be in the air stream so it would cool faster and then go back through the motor in a closed system.  What to call it though ummm circulator passthoughlator I know radiator   Sorry had to do it the joke was just begging for it.  But while we are talking about cooling the motor I work around hundreds of motors most I see are rated at 1 to 5 HP on one end is their drive shaft and at the other is a fan blade only about an inch thick with a pretty good pitch blowing air over the motor and cooling fins.  It has a mesh guard over the fan blade.  They are all fixed on a conveyor system so no air passing over them at all.  I figure it couldn't hurt as your just using the motor rpms to spin a small light fan blade.

[Cortezdtv]

Kinda like what I do on my setup, but co2> water

[dean mcneil]

check the 2013- 2014 motor swap post for more pictures and discussion on cooling.

[Cortezdtv]

And then there is mr badass cooling^^^^

Clearly not to many people clicked on the picture he posted

[Burton]

Clearly not to many people clicked on the picture he posted

First thing I did was click the link to see what was being proposed before reading anything, thinking it was some awesome flush tapped and plumped water cooling system feed off the natural vortex force of the motor through a radiator near the front of the bike (because that is exactly what we need ... more fluids on electric bikes :/ )

I then cracked up laughing

[Cortezdtv]

Sorry I meant blow up deans picture on the other thread of his go kart motor cooling..... It's interesting to say the least.....


The mist would have less effect than 1 20 oz bottle of liquid co2 blown over the fins, and does even more if it's blown inside the motor.... Single bottle will give you 15 degrees 2 bottles sprayed efficiently can bring the motor and controller to a little above ambiant temps

[ctrlburn]

Watercooling - brakes do it.

I recall back in my younger days (and others may remember better) there was a Camaro/Firebird/TransAm racing series with "identically prepared cars".

One exception to being stock I recall was a water spray into the brakes.

Googling water brake cooling still seems to be a thing. 100psi pumps seems to be in target and multiple nozzles offer plenty of control in an "undercarraige" environment.

i think it is very plausible to cool a race motor the same way. not for me though - it's raining these next few days and slipping to sub freezing temps later this week - so I don't see overheating to be problem for me in the near future.

[MostlyBonkers]

Here's a link back to Dean's post so you can zoom in on the motor:

http://www.electricmotorcycleforum.com/boards/index.php?topic=5218.msg36570#msg36570

I need to get my head around the IPM motor but one key point I've gathered from Burton's topic is that the heat builds up in the stator. That's the bit in the middle that goes round.

My understanding is that apart from the bearings, the stator doesn't touch anything. So apart from the tiny volume of air inside the motor, which isn't ventilated, there's no way to draw the heat out of the stator. That explains people drilling holes in the casing to get some airflow in there. That's a bit nuts though for anything other than racing.

Therefore the only way heat is dissipated from the stator is via radiation to the casing and a little conduction through the bearings. I'm not surprised they get hot quickly!

Using liquid co2 seems a little extreme, but must be effective!

My idea wasn't a piss-take at Lipo by the way, just in case anyone got that impression. If I do manage to get my hands on a Zero without selling a kidney, I'll give the water spray a go!

[Doug S]

My understanding is that apart from the bearings, the stator doesn't touch anything. So apart from the tiny volume of air inside the motor, which isn't ventilated, there's no way to draw the heat out of the stator.
Therefore the only way heat is dissipated from the stator is via radiation to the casing and a little conduction through the bearings. I'm not surprised they get hot quickly!

I believe you've hit the nail on the head, other than getting the terminology bass-ackwards (the rotor is the thing in the middle that turns, the stator is the outer housing that's stationary, hence "rotor" and "stator"). Besides it being difficult to get heat through the long path through the bearings, it can't possibly be good for the bearings! I'm pretty sure this is why filling the motor halfway with ATF works so well -- it provides a much shorter path for the heat to travel to the fins on the external housing. The distance between the rotor and stator windings is very small, but if it's air filling the gap it doesn't conduct heat very well at all. Any liquid will conduct heat much better than an air gap.