https://drive.google.com/folderview?id=12_oXdtElCSC63GAMmm_RNTDAJm5zYmGK
I created a post recently regarding​ a overheating motor .
I within5 hours of receiving it haverequested the seller to accept it back he is unwilling to comply.
He is ritvik  from Pune,
If any of his friends are reading this please request him to cooperate.
He says I am trying to cheat him by claiming that his motor has manufacturing defects.
Here is the link to our WhatsApp chat

I am just a student now, don't earn, buy one component a month.
I cannot afford to have a bad motor for which I have paid the asking price .
I don't understand why he won't comply.
I agreed to buy , It had a fault, I am returning it and paying for all shipping charges.

I guess it's Ritvik's turn to post a reply.

Have you enquired about the condition of the motor before buying, and at the same time, asking if the motor has such issues?

https://drive.google.com/folderview?id=12_oXdtElCSC63GAMmm_RNTDAJm5zYmGK

Yes I did..he said it was new.

Chill out buddy. There are kind hearted people to help you out. Chill yourself first

You have been talking kindly; well noted.

I'm pretty sure I know a thing or two about motors. Even in dead load, it's never a short. And it shouldn't overheat as mentioned, when used for such short period of time. That's a pure instance of defect. And in the long run, it will affect the life of the motor, pretty intensely; your battery-flight time too.

Let's wait for the seller to turn up to this post. If nothing has been done to the motor, and the buyer is very well ready to finance the shipment, then I don't see a reason to reject the refund. It's just my view.

Talking kindly is my only option.... XD
I just hope he cooperates else I am gonna feel like someone took my mom's hard earned money via me..
Anyways been a long time online ...testing and reading articles... hopefully he ends up cooperating

Can you, Vijay, by any means rent a temperature measurement device to justify yourself? Or if there's any fellow RCI member, who has one? Please enquire.

I would be glad to refund the buyer if there was some legitimate issue, but there isn't. He just decided that it doesn't "suit his needs" and is trying to make up reasons in order to return it.

Regarding the product, it's brand new. I was using it for a long time on racing miniquads and sold the used set a while back leaving this spare piece with me. I never once encountered any overheating issue with this particular model. The motors are also sold in pairs, and the other motor that was paired with the one I sold Vijay worked absolutely fine.

As I mentioned in the chat history, I would have gladly taken it back if there was some real problem like slipped magnets or a broken/burnt coil. But his reason of the motor overheating after being run no load for an extended period of time is not a valid excuse. There are a multitude of other factors that could cause this, like a faulty esc or high ambient temperate or motor screws touching the windings.

Something that I'd like to quote that Vijay said to me (not shown in pics) is "it's definetly heating up mate...I am gonna have to return it to u....Heat will turn it into a higher kv motor...". My BLDC motor theory may not be perfect, but I'm pretty sure heat cannot create copper windings to increase the kv of a motor. If by this same logic he has arrived at the motor "overheating" I am very skeptical of what he understands by this term.

He also mentioned that he read many issues about manufacturing defects with this motor online, so I would like him to post links to posts outlining the same issue he is facing.

Also, everyone has worked hard to earn their money. Just because you are a poor student (I am too) doesn't mean I should bend over and give you a refund for any reason. The motor I sold you fit your requirements and was in brand new condition.

@Imperial fire
Have you mounted those motors on a frame? Is the bell freely moving?

Yes the bell moves freely.....
I have no means to measure temp ....
Let's ASSUME his motor is perfect...infact better than it was supposed to be.
And I just didn't like it's ' feel'
Do I not have the right to return it if I am paying for shipping. 

If you feel that you have the right to return the motor because you didn't like its "feel" then I as a seller have the right to refuse to take it back.

Thread closed...I am taking care of this by other means.
Kid has a lot to learn....xd

@imperial fire. Don't mind me asking how long have you been into this hobby ?
Who ever the seller is he has claimed the product is brand new. Right ? I hope you have verified this once you received the item. Now , I'll tell you , this particular brand of motors are really good. Never have I heard of manufacturing defects from anyone , unless you know how to use them .
And one more thing in this hobby you can never be sure what may go wrong, so you can't blame the seller. It's gone. Then gone. How sure are you that you didn't mess it up while fixing the motors ?

Quote from: toxizity on February 09, 2018, 09:18:58 AM
Now , I'll tell you , this particular brand of motors are really good. Never have I heard of manufacturing defects from anyone , unless you know how to use them .

It's completely absurd. A particular brand maybe known for what's good for; but that never means they haven't designed anything that is not upto to the quality mark. I know it solely through experience. And the kid has some experience. Just because some one doesn't buy a lot of stuffs, doesn't mean they don't know how to use it.

Quote
And one more thing in this hobby you can never be sure what may go wrong, so you can't blame the seller. It's gone. Then gone. How sure are you that you didn't mess it up while fixing the motors ?

Another absurd statement. We're not dealing with something that's magic or wizardry. We're not just waving our wands and making things fly.
If something gets heated up, there is a reason behind it.
And you can't just completely blame someone, and induce a sense of doubt in one's mind who is reading the post.

Well I have one year of experience.( Gonna be in my c.v..😂..)
In this time ive made around 30 airplanes myself ...including a gorgeous sky Hunter...gliders fast ones , 3d airplanes...
Have made robots ....
Flown gas birds in nashik.. have a o.s methanol run  engine myself.
..and more relevantly.. rewound 2 brushless motors properly as a Delta config...I don't like to spend money 'I' haven't 'earned'...

So I have decent experience.. and I know I won't ' mess' up soldering a motor to a ESC...I mean what is there to mess up..just solder 3 wires....I used a turningy esc and a good hobywing ( love the music it beeps)...

I just know that a motor shouldn't get hot...( It not warm it's hot like hot chapatis) ..
He isn't willing to comply...fine... Honestly the benefit of doubt should be given to the buyer coz. A BUYER PAYS BEFORE GETTING IT AND SEEING IT WORKING FIRST-HAND...

****I am not saying he cheated me( who knows maybe he did..😋) ..all I am saying is ...I GOT A FAULTY ONE ..I DONT NEED IT..I AM WILLING TO PAY FOR ALL SHIPPING...
anyways if he doesn't comply...
I am gonna teardown this motor and FIX IT..( hopefully I don't lose its shaft screw...😂)

. Now , I'll tell you , this particular brand of motors are really good. Never have I heard of manufacturing defects from anyone , unless you know how to use them .
[/quote]

That's incorrect as arvind pointed out...even iPhones have defects...
My room partner worked for a engine making company..(rewale group in bhosari -pune ..coz genset manufacturers like kiloskar don't make their own products the outsource it to other arms or firms....just as Flipkart made ekart...simple economic- tax thing)...
Anyways
He once told me that every brand can have failed products..the thing that makes good brands good is that the failure rate is lower ...compared to others...
That's it.
Nothing has zero fail probability.

Hey Vijay! Please test the current thru the motor, as Bala had suggested in the other post. Maybe, that might give us some conclusions.
And just to clarify, is it too hot to touch at 40-50% throttle and no load?

Yes after esc motor calibration ...I hovered it gently below and over 50% ( never above 70% coz it's new and I didn't wanna push it) under no load for 30 seconds test ...yes it's getting hot,... It's not too hot to touch coz that would mean burning hot....but it's HOT..now warm...
Yes someone suggested that amp check ...but i can't find any data for this motor wrt amp draw under no load..I checked
Miniquadtest bench ,. ( They have data but not on zero load)
Online websites that sell it ( hoping to find it in specs)
And first 3 pages of Google search result..
...
Also someone suggested that high k.v motors do get hot...
I tried a friend's 2600 kv avionic motor at full throttle for 30 seconds..the motor is warm and gets hot only where the c-clip rubs the bearing...

P.s I. Don't blame ritvik..the motor is new..its wires were never even soldered b4...I just wish he would cooperate.
Anyways I am gonna fix this motor..

Here's the datasheet. The motor current draw shouldn't exceed 1A on 'no load'.(12v)

@Imperial fire

Quote from: Imperial fire on February 08, 2018, 06:26:00 PM
I have no means to measure temp... The resistance value between any 2 of 3 wires was 0.7  ..sometimes showed 0.8

Your reply in the other thread....
P. S the resistance should be around 0.06Ω
Your readings look totally off-centre 

Quote from: kiran rc on February 09, 2018, 04:43:39 PM
@Imperial fire

Quote from: Imperial fire on February 08, 2018, 06:26:00 PM
I have no means to measure temp... The resistance value between any 2 of 3 wires was 0.7  ..sometimes showed 0.8

Your reply in the other thread....
P. S the resistance should be around 0.06Ω
Your readings look totally off-centre 

The reason for resistance to be off-centred is simple. The wire length in multimeter is a factor and multimeters are not accurate at low resistance measurement. Indeed their accuracy decreases very much when you measure resistance of around 0.06 ohm.
Note that I am mainly talking about multimeters whose price is less than Rs.200.

@Vijay I would suggest you to better test the load current of the motor under no load. You need not go upto full throttle but you can check at 50% throttle where it will approximately consume 0.6A if it consumes 1A at full load. 

I do agree that measurements in a cheap multimeter will be off by a certain amount.

But how can it differ by a factor of 10? That's pretty high. Please post a few clicks of the resistance. Also the current readings at around 50% no load.

Quote from: Aravind298 on February 09, 2018, 08:17:05 PM
I do agree that measurements in a cheap multimeter will be off by a certain amount.

But how can it differ by a factor of 10? That's pretty high. Please post a few clicks of the resistance. Also the current readings at around 50% no load.

Strictly speaking it shouldn't. But that multimeter is not smart enough to think if that if multiple of 10 or something. Sometimes even if you short the multimeter probes you will see some fluctuations in readings which can be due to various reasons. Even the probes will contribute to resistance.

For calculating very low values of resistances you have to use wheatstone bridges or some kind of bridges which can give appropriate results.

http://www.industrybuying.com/digital-multimeters-mastech-ME.EL.DI.366274/?utm_source=Google&utm_medium=PLA&utm_campaign=PLA_Testing_and_Measuring_Instruments&gclid=EAIaIQobChMIw4TEjpCZ2QIVBB2PCh1MXAPlEAQYBSABEgLWtfD_BwE

If you check above multimeter you may notice that resistance measurement is not that accurate.