out door tekin settings

[gotnitro]

anyone remember where the settings should be? i have a 5.5 in the car

[haddow]

every box checked, all sliders set at maximum, assuming of course that you are running the biggest pinion that will fit.

[BCbud]

From the pro 12 thread last year quoted from Blake's post.

Some more data, after trying a 4.0 brushless motor yesterday:

Tekin RS (not RS Pro), 30deg Boost, 5deg Turbo, 5000rpm-20000rpm, 50% current limit
Rollout = 45mm

This setup has WAY more bottom end grunt than the heavily boosted 10.5 setup I ran previously.  It also has a little more top speed on the straight.  With the 50% current limit, the car was mostly controllable when getting on the throttle.  The motor was cold at around 125F after the race, but the ESC was piping hot at around 180F.  Five out of seven LEDs were blinking on the Tekin's built-in temperature monitor gauge.

[Shawn68z]

From the pro 12 thread last year quoted from Blake's post.

Some more data, after trying a 4.0 brushless motor yesterday:

Any ideas how to lower the ESC temp?  Does the 50% current limit make the ESC cooler or hotter I wonder...?  Should I gear up and lower the timing, or gear down and raise the timing?  I'm wanting to lower the ESC temp and raise the motor temp.

I am not 100% sure, but I believe the current limiter keeps the FET in their linear zone and not saturated. In other words, they are not "ON", but not "OFF" either, so they disappate the energy instead of passing it on to the motor. (Tom would no know more, its been awhile since i played with FETs).

Have you tried turning the current limiter off, and use your throttle curve on your radio?  (or a combination of the two?) Placing a small fan blowing on the ESC posts would help too.   Otherwise, switch to a HW 120A, they can handle the lower turn motors better then the tekin.

Shawn.

[ColinB]

Brushless esc's heat up from switching between motor phases. Partial throttle is the worst, as it maximizes the amount of switching. I don't know about the current limiting, but I assume it is a similar thing. Like Shawn says, remove the current limiting, and gear the motor so that you can hit full throttle more often. You could look into a fan for the esc, or air scoops?

I've never driven such a powerful car - is 50% current limiting needed? (Envisioning tire shredding doughnuts on every corner. Sounds like fun!)

Colin

[BCbud]

Sorry, I didn't mean to post that last bit that I pasted, I have removed it now. This was in response to Gerry's question about settings.

[Tom]

I think people are confusing the way old-school brushed and brushless ESC's work.

None of these ESC's will be driving the FET's linear. They'd explode in a heart beat if that were the case. There's WAY too much energy for them to dissipate!

For a brushed ESC, part throttle (or in current limit mode) the FETs will be switching in a PWM manner to limit current. So, full throttle would have 100% duty cycle, no switching, so the most efficient and cooles for the ESC.

For brushless, you're continuously having to switch anyway to control each phase, so you don't change from a switching to non-switching mode. You've also got the PWM limiting current (for either partial throttle operation or current limit operation) on top of the phase switching all the time.

I suppose turning the current limiter off would help the ESC run a bit cooler as you don't have the PWM switching on top of the phase switching, but I doubt it makes a whole lot of difference.

But, there's NO WAY the FET's wouldn't be saturated.

This is in fact the whole point of the external super low ESR caps that the ESC manufacturers supply; this reduces the ripple caused by the switching of the FETs which allows them to be saturated more quickly, limiting their time spent in the linear region switching from "off" to "on" (which is what creates heat).

So, to reduce temperature in the ESC, reduce switching. Switching has to happen anyway to get the rotor to turn inside the stator, so get the RPM's down  to reduce that switching.

I know this is an answer to an OLD post, but I just thought I'd clear some things up. It's late though so this isn't the best explanation.

[Shawn68z]

Good info.  Good explanation.. Thanks tom.


Shawn