E-board engine OVERHEATING!

[razad7@gmail.com]

Hey,
I recently built an E-Board,
Im not finished yet but it's in riding condition already.
The problem is that the engine gets very very hot when riding.
I have 2 Questions
1. Does your motor also Overheat? (too hot to touch for more then 1 sec)
2. How hot can it go before burning?
3. Is this normal? if not - why does this happen? (maybe something is not right?)
My set up is pretty standard

Propdrive 50-60 270Kv
HK 150 esc
2 30C 3cell 5000mha

Attached some pics.

Thanks.

 

[made_in_the_alps_legacy]

1. Does your motor also Overheat? (too hot to touch for more then 1 sec)
2. How hot can it go before burning?

well...
I personnaly keep as a rule what is mentionned in my "hacker motor" user manual : it should be not hot enought to hurt you, they say about 60°C.
would you please disclose your transmission ratio ? it's maybe too low... or your top speed ? it's maybe too high...
Do you ride often "full throttle" ?

 

[onloop]

Those motors are able to handle some high heat.. so after a run up big hill might be too hot to touch but still ok for the motor, but at a certain point things start to melt... like the insulation around wires.... then your motor will short out.

On flat my 270KV NTM prop drives would get warm but could hold them in hand no problems...

I have used those motors extensively, they work really well, if you operate them within their limits.

so my questions:

1. What is the gear ratio? Your wheel pulley looks fairly small.
2. What is your body weight?

2.4:1 is about that motors minimum reduction for 90kg rider, so more reduction would be better, especially with single drive.

 

[made_in_the_alps_legacy]

something weird as well :
on the driving end (motor mount side) there is usually stator holes for air to pass and flow throug the motor by being accelerated by the rotor to the non driving end :
it's like those air inlet holes are closed by the motor mount and the air is probably not able to flow enought... nice heat sink to release the heat by conduction, but maybe too much penatly on the convection cooling...

 

[razad7@gmail.com]

Hey
My Gears are
Engine - 14 teeth
Wheel - 34 teeth
That makes about
2.4 : 1 (didn't understand it you're saying that the top speed should be lower or higher?)
I Weigh around 63 KG (about 140 pounds) +/- 3 KG depending on the season (;
Top speed feels around 30 km\h maybe a bit more - but haven't checked yet - I'll update.

In this last ride I took it to full throttle to test it quit a bit. If it would of gone any faster I would have.

another issue is my engine "cogs" when i try to accelerate too fast.
(i've read about changing the timing and how it might help but haven't done that yet).
Maybe that has something to do with it.

In my mind if this engine can take 8cell bat's on the spec sheet. It's weird that it overheats with only 6cell, but i guess there are more perimeters to the equation then voltage...

 

[razad7@gmail.com]

something weird as well :
on the driving end (motor mount side) there is usually stator holes for air to pass and flow throug the motor by being accelerated by the rotor to the non driving end :
it's like those air inlet holes are closed by the motor mount and the air is probably not able to flow enought... nice heat sink to release the heat by conduction, but maybe too much penatly on the convection cooling...

Couldn't fully understand your question, but the whole motor mount is aluminium (it also heats accessibly) so that's a good heat sink i guess. - What kind of mount doesn't block those same airway passages?

 

[onloop]

motor must be over working..

try closer to 3:1 gearing ratio

 

[razad7@gmail.com]

If i got to a 3:1 ratio my top speed would even be slower though, wont it?
I get the air thing - ill try to make some air holes for it to see if it helps... kind of scares to weaken the mount too much.
could you show me your "aired" mount?

 

[made_in_the_alps_legacy]

could you show me your "aired" mount?

do you confirm that your stator is partly held INSIDE the motor mount ? (meaning that there is a machined "blind hole" as big as the motor diameter within the thickness of the mount ?)
- sorry I am not native English speaker -
usually the stator is fixed on a flat section of the mount in a way that you still see those "airway" holes... here is a version of mine...

 

[razad7@gmail.com]

Hey
The engine is indeed inside the mount.
You definitely have a case here.
like i said i will make some holes for air intake, but am worried that the mount will get weak.
Pic:

 

[made_in_the_alps_legacy]

Ok, thxs for the pic'
it seems quite obvious that the gap between the stator and the motor mount is smaller than the air intake openings, leading potentially to lack of convective cooling...
if you are too scared of drilling holes for the air to flow in axially, you could eventually machine your mount to the thickness which remains at the "motor hole" (air would flow in radially but it should be anyway much better) - great mount by the way

 

[Silenthunter]

Increase your gear ration! If you want more speed get bigger battery (higher Voltage). If the motor gets over 120-130 F degrees the epoxy will melt and the motor will stall throwing you on the concrete.

The motor should not get hot at all....this means that the energy is eliminated as heat leading to less efficiency.

 

[spinningmagnets]

Once you have opened up the air holes, Thud has shown how to make custom centrifugal fans that will pull a lot of air through these motors.

http://endless-sphere.com/forums/viewtopic.php?f=30&t=20618&p=590501#p590501