RC India

Hi every one
I have a combo of Emax motor 2215 and Turnigy ESC 30 amps  and a prop of 10 in
Every thing is just according to recommendations... But after about 5 min of flight the motor and ESC become Hot ... I mean the motor is real hot .... And Batteries are warm .....
I actually tried the combo with out load that is with out prop ... The motor is Hot ESC is warm


Any reasoning .....

Overpropping,
can you give a link to the motor.

Ashok.P

http://wap.ebay.com/Pages/ViewItemDesc.aspx?pix=4&emvAD=420x598&aid=310802824841&emvcc=0&nbcol=0%7Cnull

The recommended prop is 7 to 10

Better link ..
http://www.emaxmodel.com/views.asp?hw_id=38

Use 9 inch ep prop and 20 amp ESE 11.1 v batt

I have same combo for my sbach. U can see pic in my post on electric plane.

@kewal ... I won't get the desired thrust with a 9 in prop :(

Try running it with no prop on a 20A esc, if it still gets hot then its faulty. else overpropping is your issue.

Ashok.P

Tried running it without prop on 30 A ESC still gets hot

Should be a problem with motor or ESC, if your ESC is programmable then set all the values to default and try again,
One question here, is it warm or hot, most ESCs get warm with a 5min run but not hot.
Possible checks, see if the motor can is rotating freely, turn it with hand to hear the sound, any metal sharpnels can cause this problem.
inspect clearly under a bright light to check for motor can and armature friction.
also try interchanging some other ESC or motor to see which one is faulty.
Good luck.

Ashok.P

I have used the same ESC with a iPower 1250 kV motor without any problems ... And the ESC was hot ( it melted the epe foam used as packing ) and motor rotates freely no issues such as friction or noise ....

And to end its a brand new motor ..
 I guess I have to discard the motor :(

These points seem to be missing from the discussion.

1. Everyone talks about the size of the prop, not the pitch ! When a motor manufacturer says 7 to 10 inch prop, it should also be understood that as the size increases, you should reduce the pitch to prevent overdraw of current and heating issues. One cannot arbitrarily keep on increasing prop size just because "I need more thrust", without worrying about pitch and/or corresponding current draw.

2. It is a bad idea to run motors under no-load (no prop) for extended periods.

3. The statement "I won't get the desired thrust with 9" prop" is a clear indication that you are border-line in your power setup, which means the AUW of the plane might be too high. Always plan for power systems with enough leg room based on your model weight and flying performance required.

On park flyer size motors, roughly 45 to 79 gr weight, whenever there is a wide range of suggested prop size such as 7 to 10 inches, it means smaller prop on 3S or 4S lipo, and the bigger when using 2S lipo.

each motor is also rated to handle a maximum value of watts.  You can burn a motor even before the maiden flight during static tests if you're not careful.

I had a nice Exceed RC 370 brushlesss motor with only three flights on it.  I did everything right except fully tighten the prop adapter.  The cone/nut backed off which caused the shaft to spin without a load.  This was a case of having no prop yet the motor burnt out.

The best way to be sure is to use a watt meter.  You can see the watts and amps usage throughout the throttle range.

ranging from 2 to 8 or 10 power transistors or FETs are connected in parallel inside the esc to increase output current , failure of even 1 or more FETs will increase the load on other FETs , so they tend to heat quickly.

check for any such damage/failure inside esc.

I do not understand one thing, if there is no load there should be less current flowing through the circuit and the back EMF should be almost equivalent to the supply, but how come a brushless motor burn out with no load.
( i personally had my emax 2812 motor without prop for long time and never got warm to tough/overpropped it with 10x7 prop and it boiled out but was working fine until the wiring snapped)

Ashok.P

at high rpms(means high frequency at o/p terminals of esc) , does it have to do anything with inter electrode capacitance/inductance.....??

too much heat buildup results in high temps enough to damage

One second of WOT without a prop probably won't burn a motor but try 10 seconds will

Best Answer from Chriss:

chriss
Senior Heliman
Sunny Florida

 No high performance motor should ever be free run for more than a few seconds at a time. The motor will draw a minimal amount of current once threshold voltage is reached. This power is not being dissipated through the shaft via mechanical work so it has to be dissipated in heat through the case of the motor. The net result is that the motor will become over heated in a short amount of time.

Yes, Kv is the rpm/volt of the motor. It and Kt , the torque constant (in*oz/amp), are related through the constant 1355. If you know one you can determine the other mathematically. Kv*Kt=1355

In a brushless motor, there is really no reasonable upper limit to rpm. The only things limiting it would be from the centrifugal force on the rotor wanting to throw it apart or the bearings. If the motor is well balanced and solidly constructed, it should be capable of very high rpm's.

It is always best to setup an electric motor system so that most of the time the motor is at full throttle. This is due to the inefficiencies of the speed controls when opperated at part throttle loads. But, the motor also has a happy current it wants to run at. When setting up a new system, you should always endevor to keep the motor loading close to the maximum efficiency point on it's load line.

Check the Aveox site for some good info. Also Astro Bob's motor handbook is a good source of info. Most of it is about brush motors, but the info is pretty universal.

Chris

I think you can use 10x4.7 prop for good thrust with 30a ESC.
One more thing, air ventilation is also necessary element to cool electronics.Did you balance your prop? Is your plane scratch build? What is weight? can you post pics here,,

@docnayeem
Buy or borrow a wattmeter.
Without power reading, these discussions lead nowhere.
But motor hot, esc hot, battery warm all indicate overload.

@docnayeem
Which 2215?
What pitch?
What rpm on full throttle?

wat thrust u want?

Use only 20 amps .30 amps is not suggested from my side.

Care:
Emax's own data (rpm on 10x6) seems suspect or misprint

My 2 penny worth:

What gauge of wire are you using in your setup? I've faced a similar problem when I had to use 18 gauge wires and everything was heating up. Once I switched to a thicker 14 gauge, things were 'cool'. Of course, this was on brushed set up and I remember raising a similar query on the forum on my Mermaid build.

@kewal ... From what I know a ESC of an higher rating is always better ... As it does not cause any  damage .. But a lower rated ESC will definitely burn if you load it excessively ..Seniors ... Correct me if am wrong

@VC Sir ... There are no extensions used all the wires are the one that came with the stock motor and ESC ...
By any chance does ventilation play a major part ?

@K K Iyer ... The motor is Emax GF2215/20 prop is 10*6 ....
Does higher pitch also overload the motor ?

yes higher pitch overload the motor. 10x6 is not recommended for this motor, that is why your setup is getting hot. Recommended props are, 10x4.7
and 10x5

sory my frnd u r wrong. Do u know y kV, resistance ohms and  watts of motor is mentioned in there specification? Bro it is not useless information. With that info we can make good electronic combination so there is no need to see on chart for combination. Bro for ur kind info I strated motor winding experiment wen I was 8 year old.

Have u program ur ESE for ur motor or u kept default?

@kewal .. I have high regards for your knowledge... No doubts about that ...
Its just that the KV .. Resistance and wattage are defiantly mentioned for a reason ... But here I guess u have some confusion coz the current drawn by a motor on a specific load is mentioned that is for a particular prop the current drawn by a motor is fixed you can use any ESC greater then that max current drawn ...
Like if the maximum current drawn by a motor is 20 amps you can use an ESC with 25 amps or 30 amps or 35 amps with out any problems in the electric configuration ...
( except it will increase the  AUW )

@kewal just for your reference
....
http://www.modelairplanenews.com/blog/2011/05/29/choosing-a-motor-speed-control-battery-pack-taking-the-mystery-out/

bro for simple example i m giving u how to check esc amps for motor which can run on 11.1 volt. jut devide watts given.

Motor: Avionic M2028/12 KV2300 MICRO brushless motor
KV (rpm/v): 2300
Power: 65W
volt 7.4

now ese will be = 65/7.4 = 8.5
so 10  amps ese is much suitable than any other ese.
 

in other example


rc bazzar has listed some motor 1of them has as following specification

Motor: Avionic M1818/17 KV4500 MICRO brushless motor
KV (rpm/v): 4500
Power: 30W
Winds: 17
Resistance: 263 mOhm
Idle current: 0.8 A
Weight: 9gms

Combination of usage:
PROP - 6x4 E
● Get  300 gms Thrust
Lipo - 2 cell 7.4V
ESC - 20 amp



now see the are using 20 amps ese

if u calculate 20*7.4 is 148 watts
which is greater than the watts given in detail.
it can burn ur motor or batt.


i have same motor cobination with 6 amps ese. it works great with no heating stuff.

bro this easy tricks for u bignners to select ur combination and save ur electronics.

Can you explain why you feel docnayeem is wrong and using a higher amps ESC is a problem ?  You have said nothing in way of "why" except to point to specs and talk about your experience.  What is the technical reason why a higher amps ESC would be a problem ?

PS: Please take extra 10 to 15 seconds while posting to write proper English and DO NOT USE SMS language !

@kewal yes you are right .... But confused ... What you are calculating is the maximum wattage the ESC can support ...
The actual max wattage ur  motor can give is 30W and you are using a 6 amp ESC  so your ESC can support a max wattage of 42 watts that's quite above the actual wattage of your motor that is 30 ...
Even in this example a higher rated ESC is used with out any harm ...
I hope you get the point ...

@docnayeem  battery and ese combination should not exceed to the watts given for ur motor.

sir i have already given simple example for selecting combination. if u want perfect technical reason than it has  big explanation and it should need to take lecture.

battery and ESC combination  should exceed than the watts given for ur motor...... Motor pulls the desired current from esc and battery.

if its not exceeding you may have low performance from motor. There is no harm in having power reservoir for motor. in case if excess current drawn ESC will autocut (choose Esc with such feature).

@kewal ... You seem to be confused again ....
Let me explain
The motor draws a current depending on a load ( the prop ) your ESC  should be able to deliver that current ... Say if your motor draws 30 amps your ESC should be able to give 30 amps of current ... So a 30 amp ESC or a 35 amp ESC or a 40 amp ESC will be able to deliver the required current .... A 40 amp ESC used does not mean its pushing 40 amps current to the motor ... The motor will draw only the required current according to the load .
The battery and ESC combination will decide what max motor it can support ...
I hope your confusion is cleared

I have all the time in the world for you !

You have got your basics (and the simple example) entirely mixed up !

See this post, there are tons like this on this forum.  In fact you should start by reading this thread :

http://www.rcindia.org/electric-power/understanding-electric-power-systems/msg44026/#msg44026 (http://www.rcindia.org/electric-power/understanding-electric-power-systems/msg44026/#msg44026)

The question is quite simple. Why should I not use a 30A ESC in a place where even a 20A ESC may work just fine ? Please think about the reason.

Kewal your 3D planes will have much more power and punch if you have a bit higher capacity esc and motor.

we all know that the mentioned stats are with +- variations so having higher side is better.

In fact, just brush up the stickied posts at the top of the "Electric Power" board.

http://www.rcindia.org/electric-power/ (http://www.rcindia.org/electric-power/)

The normal recommendation is that you should always use an ESC that is slightly higher than what is needed for the motor.

http://www.rcindia.org/electric-power/amp-rating-and-motor-size/msg1566/#msg1566 (http://www.rcindia.org/electric-power/amp-rating-and-motor-size/msg1566/#msg1566)  (see the reference to "Sizing of the ESC: The ESC has to be sized such that it exceeds the maximum rating of the motor so that it can operate all load conditions of the motor.")

http://www.rcindia.org/electric-power/lipo-selection-for-motor/msg34361/#msg34361 (http://www.rcindia.org/electric-power/lipo-selection-for-motor/msg34361/#msg34361) (see this post also, and read this whole thread).

sir plz read all post care fully before giving sugetion on my 3d model. Have seen my all modes? I have models from 10 gram to 4000 gm  and 100 km to 2000mm size and all are electric. I have 100 of models design by me.

The proper way to choose an ESC has been established.  The OP was about troubleshooting and the causes for a hot motor.  

What is hot to me might be different to others.  The general guideline is if you can't touch it for more than a second then it's too hot.  A better more accurate method is to measure the temp and use something like this for Rs 600

http://www.hobbyking.com/hobbyking/store/__8297__Turnigy_Infrared_Thermometer_33_180Celsius_.html (http://www.hobbyking.com/hobbyking/store/__8297__Turnigy_Infrared_Thermometer_33_180Celsius_.html)

For all we know, the temps of your motor and ESC are within specs.  But what we don't know is if you are using too big a prop.

Invest is a watt meter, fairly cheap considering you don't want to burn out an ESC in mid-flight, and you'll see before your eyes the difference in how many watts and amps a 9" prop and a 10" prop will draw.  Once you have the numbers, you will save lots of time from writing and reading these posts. No more guessing.

It can't be any more simple than that.  

kewal kalsaria and rastsaurabh, when you guys hijack the thread and go off in a tangent, it's distracting and not helpful to the OP. 

Hi everyone thanks for all the inputs .... Ventilation was the problem ... Increased the size of ventilation inlets and outlet .... Things are cool now ....

I guess ..Ayub had pointed out the probable cause thanks ...

Docnayeem, congrats.

Its a pity that I wasn't following this thread closely. There was so much to be learnt / unlearnt thanks to some of the experts here. I'm still a beginner and will probably remain one for the rest of my life. What I fear is that some keen newbie will start reading this thread and once he stumbles upon authoritative drivel being pumped in by an 'expert', will take it as Gospel truth and log out of here. How long before failed flights and frustrations 'burn' his enthusiasm for the hobby?

May I request all the self professed 'experts' (not deemed by your number of posts but self declared in your own profile against 'RC Skills') to be very careful in your 'teachings'?

I am still a beginner (after being associated with this hobby since 1975) and am trying to learn here. What, I'm still trying to figure out, is an ESE?

Thanks VC sir ....
And its so very true there is always so much to learn ....

And its humble people like you that keep us inspiring to learn and unlearn
Thanks again ... Happy to have people like you Anwar  sir and everyone else around making it a great learning experience ....

Well Kewal Kalsaria is missing with prolly with tongue in his cheek looking for the prodigal cat.

1. Ventilation is important, here is the image from my previous thread, you can see how these transparent plastic cups traps the air and blows it onto the motor to cool it
(http://i1119.photobucket.com/albums/k629/augustinev/PA%20Bandit/Build/th.jpg)

2. While it is theoratically true that motor draws required Amps depending on the load, if your ESC is not upto it (That is if it is 20 Amps ESC and the current required is 30 Amps) ESC will burn

HOWEVER what i have practically observed when a motor draws 19 amps WOT when i use 25 Amps ESC, same motor draws 23-24 Amps when i use 40 Amp ESC, gives me more RPM, power and punch, particularly true for higher KV motors like the ones we use on parkjets.

3. I agree completely with Lance, investment on Wattmeter is a necessity (Even to Kewal, i would suggest that), Like they say in Hindi "Darpan Jhoot Na Bhole" Mirror doesn't lie. Wattmeter meter and RPM meter tells you exactly what  your is motor upto

(http://www.brchobbies.co.uk/catalog/images/408057%20watt%20meter.jpg?osCsid=a64664192190a348a976f41ced5ff847)

Respected  rc pilotacro plz mind your language, as I did not object for ventilation in my any post and decision was started to share knowledge to make internal conflicts or to use vulgar language. Please next time take care of it.

Kewal

(a) Like it was pointed out to you please dont use SMS language and what your post, post it legibly, calling ESC as ESE are few examples which were pointed out to you.

(b) Tongue in Cheek means this http://en.wikipedia.org/wiki/Tongue-in-cheek (http://en.wikipedia.org/wiki/Tongue-in-cheek)

(c) Cat caught your tongue means this http://www.phrases.org.uk/meanings/cat-got-your-tongue.html (http://www.phrases.org.uk/meanings/cat-got-your-tongue.html)

Your Tongue in Cheek reamrks which did expose your ignorance are as enumerated below :-


Red ones are not accepted around here, you need to take care of that, if you knew and yet you dont follow ? expect to be ticked off, mildly initially, later...?

Why is there no need to see the chart ? by just reading KV watt etc how will you know which size prop to use ?

Does starting a winding shop when you were 8 yr old make you an expert in Electricity and Magnetism ? If so What is Lenzs Law ? how does it matter ? with the correct prop and incorrect prop will the motor overheat, if so why

Refer my PM on my stand on the subject of vulgarity, edit your post

 :salute: wonderful outcome; motor need little more fresh air!

Lighter side of the discussion!

years back Chacha Chaudhary was a big name in hindi comics :bow:.... in one of his stories a man got a new TV and he was not able to start it; all the experts tried everything in the TV but not able to start it and finally chaha went and just plug the 'unplugged' TV and it started :banghead:.

It also remind me the story of Alchemist! what you want is exactly there where you are sittting.... but its always good to roam around the world and realize this fact.

Wonderful discussion! lot of knowledge sharing!  :thumbsup:.... and good that outcome was as simple as 'little more fresh air'

Keep going :thumbsup:

Respected rcpilot sir as u you are Senior I respect u so I don't want to create any personal despute between us so I strongly apologise from my side.

That is a great attitude  :hatsoff:
This is a good forum, so make it more useful.

Kewal

so do i, like i said in my reply to your PM, english banters are just banters and need to be taken that way, if you notice, pulling leg here and there keeps the humour alive, vulgarity is not to be and never used. I was only bringing out the relation of how important it is to select a correct prop for an electric motor depending on the number of cells you use for an electrical setup.

Once again, if by my Errors or Omissions or for that matter Commissions, if in any way you felt hurt, unconditional and heartfelt apologies. :bow:

 :bow: With your kind permission can I use this line for my any of my unintentional "future misbehaves" with anyone to seek an apology!!! (Actually a permission to do CCP from here  ;) )

:) ;) Iyer sir, I , Mrs Iyer and Iyer sir's father, Doc Vikas Harveer and I were discussing last light over dinner that, owing to some gentlemen here (me inclusive i guess) this forum is also turning out to be a good place to hone ones writing, thinking and probably speaking skills in English, (Humour inclusive)

PS
Go right ahead

:))