BHT motor mods and cooling

[nutnspecial]

There are a few of us running these motors now, and I'd like to explore as a group the best mods, inparticular cooling.

I'm finding that sustained high draws of 5-6kw while only running the motor to 30% max of it's top rpm make motor heat the weak link in the chain. Running 20mph max with full draws on a small circle mud track heat it up fairly quick. I doubt even rolling up a mountain would compare.
I can cool it down quickly enough by hitting some flat road and running it >30mph while pedalling, which gives good air cooling while the draw is around 10%.

Cooling modes to consider:

exterior fan cooling-
. . shaft mounted fan
. . independant fan

venting covers to open air
. . venting covers and forced air

liquid cooling
. . liquid cooling and forced air


I'm leaning towards trying the last one, although the motor shaft exit will need a seal I suppose? I have about 1/2" to bolt a fan to the shaft, but wonder what fan style and how effective it will be to just push/pull air against that one side.

Also, how much is oil really gonna help when it's main purpose is to improve heat transfer, and the bht already seems to do that very well.

 

[upek]

Good sealing is biggest advantage of this motor. Becouse it is inrunner drilling and venting it inside is just waste - better is change to outrunner (Revolt RV120 Pro)) and push air through it.

In my opinion best idea is just make pipe around it and high speed fan on one side(forcing air between motor fins and pipe) - just like lot of industrial motors.

Liquid cooling - too much hassle at such low power motor - again, better change it.

 

[nutnspecial]

Don't those other motors all spin 2-4x the speed (bht 2500rpm@85v) though? That makes single reduction hard if not impossible.

 

[upek]

Revolt is quite slow, 45kv - only 25% more than bht. You could also wait for new , bigger 160mm revolt or buy longer bht-style motor.

 

[nutnspecial]

If you think there's a better one- please link to where it's been successfully used in a single reduction parallel drive.

Other than that this thread is kinda about cooling and mod'ing the bht, not 'changing' it :lol: .

 

[nutnspecial]

I am under the assumption this motor is currently the best power for this application.

So have any bht owners done liquid cooling or a shaft mounted fan?

Maybe I will be the first then.