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Old 09-29-2006, 03:55 PM   #1
Richard Parkes
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Default How hot does a 30 Amp esc get @ 20A

Is anyone running a Tower Pro 30A esc at 20 amps continuous. Im building a scratch 777 that has 2 EDF's each drawing 20A. The Esc is mounted in the 3/4" wide engine nacelle, with a 20Amp power wire and short cables to the brushless motor I am trying to decide whether I should I duct some of the flow from the EDF over the Esc to cool it.

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Old 09-29-2006, 04:48 PM   #2
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Richard,
is that 20A continous at full throttle? If so you should be fine, in fact the bigger issue for cooling the ESC will be how many servos will you be running off the BEC (I'm assuming on that:o) and how many cells you are running.
Please post more on your project, as it sounds like an interesting build.
Cheers,
Pete
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Old 09-29-2006, 05:23 PM   #3
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Default 777 details

Boeing 777 1/50 scale, 47 1/4 span, 300 sq ins, 4.5" OD fusalage
Target < 36 oz auw 196w/lb 17oz/sqft
Scratch design from 3 views trying to hold to scale as much as possible
All from 3 & 6mm Depron with some ply and carbon rods.
Wing planform with flaps set at 20 degree position for increased projected area, and reduced wing loading. Aileron size increased above true scale but running with scale dihedral in tailplane and wings. Aileron's operated using 2mm carbon torque rods running through the centre of the 6/4mm carbon wing tubes and a single central servo.
Each motor pod fitted with HyperFlow 56mm EDF - the Performance with Brushless 24-45-3790 motor is stagering:
3Cell 11.1V 19.9A 221W THRUST 450g (15.9oz) 38,600 Efflux speed 135.89 mph
Using Welgard P type 4000mah 10C pack, and 2 off Tower Pro 30 Amp escapes.
Hyperion 4 channel Rx, plus 3 Bidproduct 1.6kg.cm, 0.12sec/60deg, 100mA 9g servos
Wings now pretty much complete, fusalage in 3 pieces, all rolled depron. The rear one is removeable containing all servos etc and the tail surfaces.
There is plenty of air flowing through the EDF and I thought it would be easy to follow full size practice to provide cooling air - hence my thread.
Ive bought a digital recording system to capture the actual electrical performance in the air - thats going to be interesting.
A bit of an ambitious beast really, but then what else do we do with our time !
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Old 09-29-2006, 05:39 PM   #4
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Awesome project Richard!
I would go with your idea of using some of the airflow for cooling the ESCs.
I hope you will post some pics in the future and a flight video would be neet.
Pete
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Old 09-30-2006, 01:04 AM   #5
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Especialy the ESC that is powering the receiver, it would be the one with the extra load of the servos. That ESC would run hotter/warmer than the other.
The other BEC wouldn't be working and would not make the heat that the other ESC would reducing the voltage down to 4-6 volts for the flight package.



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Old 09-30-2006, 04:33 PM   #6
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Default Hot ESC

I had planned to cut one of the Esc + wires so that I had twin ESC 's driving the 2 motors. Would it be worth switching off the BEC facility altogether and using a separate servo/Rx supply even tho it would mean a weight penalty. It has the advantage of a 6V option to the servos and a bit more pace / torque doesnt it ?

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Old 10-01-2006, 04:33 AM   #7
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Default

That would be one way to go.

Looks like what you are building would work fine as you have designed it. If it was a larger craft with more servos or bigger servos I would consider the extra battery which would be the belt and suspenders theory. You would have control at all times.
you would never have voltage cutoff from too high a draw, as I have seen happen with too many or too big servos all working at the same time.



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Old 10-03-2006, 10:28 PM   #8
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Default TowerPro 30A esc

I have decided to play safe and use a separate 700mah 6v supply for the R/C gear. I've hunted hi and lo for any info on disabling the BEC function of my 2 off 30Amp TowerPro Esc's. Anyone know how it can be done - is it as simple as disconnecting the 2 + wires and just taking the 2 signal and -ve's to the RX ?

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Old 10-06-2006, 02:47 AM   #9
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I had a twin EDF with 6 servos and 2 towerpro 30A ESC's I "y'd" the ESC's on ch3 and had ZERO issues with the BEC....

BUT
if you do want to disable the BEC's just snip the signal wire..be sure to leave room if you want to reconnect it

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Old 10-11-2006, 06:45 PM   #10
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Better than sniping the actual esc wire, use a short servo extension and snip that. Then if you ever decide to use the onboard BEC again there is no hassle.
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Old 10-11-2006, 07:15 PM   #11
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Thanks - excellent suggestion

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Old 10-13-2006, 07:57 PM   #12
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Originally Posted by MAKODS View Post
Better than sniping the actual esc wire, use a short servo extension and snip that. Then if you ever decide to use the onboard BEC again there is no hassle.

that is a GREAT idea...thank you for the tip!!!

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