a_sprague

<!-- / icon and title --><!-- message -->Any ideas what might be causing my new brushless to smoke?

Its an E flite 400 (920kv) with a 10 x 7 prop - 30A DualskyESC - 3S 2250 li-po - all on Multiplex Minimag

It has been flying fantastically for a week or so -

but now about 5 secs of running the motor it is far too hot to touch and smoking a little then cutting out.

Is this likely to be engine or ESC failure? Any ideas or advice for diagnosing and resolving needed please!

Thanks
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Will Hicks

Likely a motor.

How many amps are you pulling with your setup?

a_sprague

In all honesty I do not know...I am fairly new to flying and have heard amp meters mentioned but dont know extactly what they are or how to use one!

Thanks

EpoweredRc

Sounds like you cooked the motor, is that the set up they suggest on that plane?

TeslaWinger

A_S I smoked a brushless once before I got a WattMeter. It ruined the battery - one of my first lipos- also!

Come to find out, it would have been perfect with a 2 cell but I had a 3 cell and took my chances. Performance was great for 3 minutes or so till it bled smoke and shut up forever! One flight with that new BL and battery! The ESC had melted the label a bit but lived to fly again.

One too many cells or too large a prop will push the motor, esc and battery too hard and HEAT is the byproduct of power.

There's lot of posts about WattMeter type devices and I will never again risk destroying such good equipment by blindly putting together a system. I use it on all my new startups.

Do a search for WattMeter (there are many others but I like mine) here on the site and learn what is missing from your tool kit before lightning strikes again! It gets REAL EXPENSIVE without one! Haven't had a single such incident since- and my equipment lasts for yrs of great flying! Sure do miss that gem of a BL!

Good luck- and GET ONE!

TeslaWinger

One other thing...

Check to see that all 3 wires to the motor from the ESC are secure. One thing a 3 phase motors cannot endure is losing one of the 3! It's called Single Phasing and is a very unhealthy condition leading to severe heating.

I had a bullet conector come lose during a flight, and tho I heard it change pitch, I didn't realize what had happened- till it went silent and became a glider with a cooked motor! I tape them now!

Good luck,

TW

jimmi

Very good info TeslaWinger I was also going to state to a_sprague to make sure and see if he is running the correct setup for that model. Diffrent prop or diffrent battery makes all the diffrence. And I didn't know if one wire would come loose coming from my motor that I could fry my system. So I will secure the leads with some tape even though there on pretty tight. Thanks and happy flying, Jimmi

USAPatriot

Here's a link to Amp Aviators and a really excellent article on the hows and whys of brushless motors melting down. The article gets to the nitty gritty of amperage, heat and magnets. It's definitely worth the time to read it over. It runs 4 pages: http://www.ampaviators.com/index.php...d=55&Itemid=31

Franny

Hi A_Sprague,<o></o>
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I am running several E-Flight 400 (920KV) motors on three cell 1320mAh lipos and I run a 9X6 prop. I think the 10X6 will pull too much current... It can only handle 10A continuous... You might want to smell your motor - they do smell stinko when they burn up... I think your 2250mAh pack is too serious for this little guy. The battery can deliver over twice the motor's current capacity at just 10C (10X2.250 = 22.5A). If you load the motor with a larger prop and you battery can deliver it, it will pull past the amount it can handle. Unfortunately, your motor is probably space toast... Your speed control looks like it can handle more than you battery could safely deliver... You might want to look into the 480 which can handle 20A.<o></o>
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Franny

cyclops2

All motor types of bullet connectors are not reliable, COMPARED to a small 3 terminal strip. I had 2 new GWS 2208's with not tight connectors. Do away with them. Butt splice the motor to the ESC if you have to. AFTER you get the right rotation of the prop You DO NOT want a easily movable connector anywhere. It is death to motors and ESC's.

How long till death, varies.

Bill G

My 12mm Feigao bl motor got so hot, it melted off of a GWS IPS gearbox.
I mounted a 180 on the same gearbox, and basically did not have to cutaway the portion of the plastic gearbox frame that mounted the original 12mm Feigao, since it was gone.
http://www.wattflyer.com/forums/show...4&postcount=54

Bill

Dr Kiwi

If you look at Motocalc it suggests that your 10x7 is pulling 15.5A (157W) - since the motor is only rated for 10A continuous - therein lies the problem.

The best investment you can make in this hobby is a Whattmeter of some sort!

Bill G

Probably would have lived with a 9x7. Did you run that size?

I don't know about the Eflite 400, but if I remember correctly the Eflite 370 series outrunner allows more current on the higher kv version, and I think 1 of the 2 motors in the 370 series is speced for 2s use, although current (due to prop load) is really the deciding factor. Maybe not as efficient as the lower kv motor, but I don't run many 2s speced lower kv verisons of motors.


Bill

solentlife

eCalc ..... best online motor calculator program there is.

Designed by a model flyer ...

As to one bullet / connector parting on a BL motor ... the motor will stutter and not fly the model. You will know immediately it happens.

Wattmeter ..... plenty on eBay ... Hobby King ... and not expensive ... mine was about $15 ... includes multi balance board as well.

Abuelo

I have that same motor and have had no issues with it. Also have the printout of specifications and features.

Voltage is 2-3 LiPo batteries
Prop is 9x7 to 11x4.7
Continuous current is 10 amp
Maximum burst is 13 amp
Speed Controller 10-20 amp brushless (your 30 amp should be fine)

What it doesn't say is what prop goes with which voltage.

My opinion, for what its worth, is to go with the smaller option with 3 cell batteries and the larger ones on 2 cell. Your choice was right in the middle and I think it should have been OK, and it was for awhile, but was marginal.

As suggested, get a watt meter, figure out how to use it, and use it. I even use mine with my charger.

ron_van_sommeren

Nigel, Abuelo, all good and sound info, but alas, this thread is from 2007, and TS has not been online since mid 2009.

A poor motor contact can even burn out motor and/or controller. Don't play with throttle when motor stutters.
Possible causes and solutions:
Motor stuttering? Won't run? Read before asking. - RCG