Power, Torque. 9L vs 10L

Hello,

I'm a little confused and hoping someone can set me straight. I know that a 9L has a higher number of revolutions per volt than a 10L but which has more torque assuming the SAME input voltage?

For some odd reason I always thought (with brushed motors) that lower winds had more RPM but less torque. Recently I was told that is incorrect, a 10turn brushed has more torque than a 12turn brushed. I'm wondering which is the case in brushless.

Thanks!

DM

[ttrmike]

Originally Posted by MacII

a 10turn brushed has more torque than a 12turn brushed.

That is incorrect.

[studysession]

I have the 10L Feigao in my Hyper 7 PBS and it flies on 12 cells. Lots of torque and speed.

http://www.rcuniverse.com/magazine/a...article_id=467

So which has more torque the 9L or the 10L.

[ttrmike]

They can't be much differant from each other. I think the 9l would have more torque because its higher kv rating. But that is just a guess.

it depends on how many cells you run the motor on

Like I said, assume the same voltage. Which one has more Torque. There has to be a chart of this kind of thing somewhere...

[Serum]

Both have got the same torque. (the power the magnet can translate from electric energy into torque is the same)

the 9L will turn faster and can be geared a bit higher. the 10L will give you a longer runtime though and will run cooler.

[GriffinRU]

9L and 10L are rated to the same maximum power.

But power is torque*RPM, so 9L has less torque then 10L.

Artur

This is the wall I've come up against. One guy says one thing and another says the oposite.

If

Power = Torque * RPM

Then

Serum is right and GriffinRU is wrong and the 9L has more Power

Or

GriffinRU is right and Serum is wrong and the 9L has less Torque.

I'm sorry to play you guys off eachother but the two statements can't be right unless the equation is wrong. I had a 9L which died and now I've got a 10L, I'm getting ready to replace it but I'm not sure which to get. Just thought knowing torque would simplify the purchase decision.

if you want more torque than go with an xl motor.

[Serum]

the maximum power the magnet can handle is reached at a certain point. at this point, both motors will have got the exact same torque because they use the exact same protocol to translate the electric magnetic energy into torque..

if this is neglected, or if this 'satisfaction' point is not reached, then yes, a 10L will have more power.

[coolhandcountry]

Well if the power = torque x Rpm The 10 L would have more torque at the same power for it has a lower rpm.
I think the 10L may have it by a fraction but it is not a great deal. The question would really matter is the amount of cells you have or plan to run.

[studysession]

Keep in mind that - The lower turn motor will give less runtime and get hotter quicker.

[GriffinRU]

Originally Posted by MacII

This is the wall I've come up against. One guy says one thing and another says the oposite.

If

Power = Torque * RPM

Then

Serum is right and GriffinRU is wrong and the 9L has more Power

Or

GriffinRU is right and Serum is wrong and the 9L has less Torque.

I'm sorry to play you guys off eachother but the two statements can't be right unless the equation is wrong. I had a 9L which died and now I've got a 10L, I'm getting ready to replace it but I'm not sure which to get. Just thought knowing torque would simplify the purchase decision.

It all depends on how many cells you attach to motor...

For a example (not true for given motors, do not have datasheets):
At 12 cells 9L can produce more torque then 10L, but at 16 cells it would be opposite. In first case 10L doesn't have enough current to generate torque, while 9L is a top performance, in the second case 10L gets to its top - while 9L past sweet spot. So in first case 10L stays cool and acceleration sucks and in the second one 9L overheats (efficiency down, excessive current draw...) while 10L runs normal.

Artur

P.S. Check labels on both motors for current ratings, 9L has higher numbers, because rated for lower voltage at the same can size (rated can power)

What are the torque defining parameters?

Magnet size, Number of turns and core size
Both motors have the same size magnet and same core size. Motors with higher number of turns have more torque, with less have higher RPM at given Voltage all the rest is efficiency!