I live in Italy my name is Paolo.
practical modeling for a long time.
lately I fell in the quadrimotors that intrigue me a lot.
I apologize for my english.
I have a problem with esc kiss 12A and new racestar br1407 engines.
I burned two engines and two ESCs without propeller.
I can not understand why.

Hi Paulo, Welcome to the forum.
I have no experience with brushless motors and ESC's, but off the top of my head, the only thing I can think of is the motor mounting screws might be too long, causing a short in the motor windings?

You say the motors and ESC burned 'without props,' did you ever get it to fly or is this the 1st time setting it up on the bench?

Hey Paulo,

Welcome to IntoFPV! If you were looking for a spot to get some help with your problem this is definitely a place with some good resources.

One thing that may help us troubleshoot is to tell us more about the rest of the setup... such as what sort of battery you're using (2s/3s?) which props you're using (a link to those props would be great) and a little more details about the events that happened when it failed... For example you tell us that the props were not on at the time when the "burn[ing]" happened but what were you doing before the failure (crash? flying without problems? replaced specific components etc?) and what exactly happened at the time of failure (was there just magic smoke, or did you see sparks and flames etc?)

You can specify all of this here in your intro thread and we may be able to provide some help but it might get even more attention if you post it in the beginners or brushless micro sections.

I am still learning myself so I don't know for sure that I'll have the answers but I think knowing some of those extra details will really help someone with the experience to give you some help.

(10-Sep-2017, 05:44 AM)Tom BD Bad Wrote: Hi Paulo, Welcome to the forum.
I have no experience with brushless motors and ESC's, but off the top of my head, the only thing I can think of is the motor mounting screws might be too long, causing a short in the motor windings?

You say the motors and ESC burned 'without props,' did you ever get it to fly or is this the 1st time setting it up on the bench?

Hi Tom
Thank you for the reply.
long screws were my first thought, I checked several times.
the model is still under construction, Esc Kiss I have taken from the old model, and have always worked perfectly.
the engines are new, and for the first tests they worked.
yesterday I was testing the new card features that Ampere and watt consumption.
after 9/10 seconds with the engine at maximum revs The ECS has exploded and the Motor is smoking.
short circuit winding and Esc to throw.
my doubts are:
1 the motors are of poor quality
2 motor are not compatible with my Kiss 12A, the maximum engine consumption should be 10.5 A.
3 I did not have to test these motions at the max of laps with the DYS 1806 and BX1306 never happened.
some idea ? what do I need to match?

Hi Carl
Thanks for the welcome.
the quad has never flipped, it is still under construction.
the first MOTOR and ESC was burned after Clenflight's ESC synchronization, it worked for 10-15 seconds.
use 3s battery.
I'm new to forums I've always read and never written, if I'm wrong to explain how to do it,
I also thought maybe it was better to open the post from another.

(10-Sep-2017, 10:52 AM)Giangiacomo66 Wrote: I'm new to forums I've always read and never written, if I'm wrong to explain how to do it,
I also thought maybe it was better to open the post from another.

Not a problem at all this place is pretty flexible and I've seen intro threads do well to get people help before. I just was suggesting in case you have any troubles. For now since we've already got the ball rolling here this is probably a good spot to keep it all. 

I still don't have any ideas myself but my next question that comes to mind is which motor protocol are you using?

Hopefully one of the guys or gals with more experience will come along with some ideas soon for you

use oneshoot 125, as on the old model.

It's risky to run full throttle without props imho - the motors can get into some kind of self-oscillation without the dampening effect of prop weight. Also, if you ran this test using your transmitter instead of motor tab in configurator, it means PID were active, so any vibration or too high PID may have resulted in additional heat...

Also they will reach higher rpm than they would without props. I don't know what kV your motors have, but i know the old kiss escs are limited in that regard - maybe you went over the max rpm.

Hi FFTUNES
it was one of my hypotheses, I also found an old thread on ESC KISS that says:
"Because of the high number of eRpm engines such as 1806 2300kv, 2206 2000kv or 2206 2350kv on 4S without any problems, KISS 12 & 18A ESCs can be selected in eCalc now: http://www.ecalc.ch/indexcalc.htm Come General advice: Economic motors must be handled with care! Driving to the limit could highlight magnets and glue until they are lost and not only destroy the entire engine but also with ESC with it - heat and intense fire will be the result. "
imotors are the br1407 3500KV.
what small ESC would you advise me?
Thanks in advance.

Hi Paolo and welcome to the forum!

Running the motors without propellers should not cause a problem. This is how the kv rating of the motor can be measured and if you look at this video



you can see that EngineerX does exactly that on his thrust stand.

As you can also see, running at full speed without a propeller draws very little current, so I doubt if the ESC or motor overheated.

If you were using a 3S battery then the motor speed would not have exceeded the ESC's maximum of 300,000 eRPM. It would have got to 265,000 at the most.

So, the only thing I can think of that would make this happen is a short circuit of some kind. Either in the motor or the ESC. Are the ESCs properly insulated?

Can you show us some pictures of how you have everything connected?

I see already plenty of help regarding the issue you mentioned, so just a big welcome from my side!

Cheers

thanks for the greetings and the answers.

now I dismounted ESC Kiss to test with old ESC pwm, it seems to work fine

the connection was very simple:

all wires welded and all covered with shrink wrap attached with double-sided adhesive.

I checked that the wires do not touch the engine chassis.

they worked for a while, if it was short-circuited a wire I got a solder burnt right away.
now I have ordered ESC DYS DS20A.

Well, I'm all out of ideas why your KISS ESCs blew up and burned your motors. I hope the new ESCs work better for you!

Actually, now I think about it a bit more, there is a risk in running very high kv motors like these without propellers.

If the ESC timing is not high enough then there's a good chance that the ESC will lose synchronisation with the motor at full throttle. If that happens, it can cause a massive spike of current. The wires on these motors are quite thin and that spike could very rapidly overheat one of the motor phases and cause a short circuit in the motor.

Once that happens, your motor and the ESC will be ruined.

When I have my motors fitted to my quad, the only testing I do it to check that they rotate in the correct direction and check what the minimum throttle should be to make sure that they start up reliably. Once that's done, I mount propellers and go fly!

thanks for your answers.
given Kiss's notes and your reflections, I can conclude that turning these motors to the maximum have spun the windings and as a result ESCs have exploded.
we'll look at the ESC DYS nuts that give high rpm engines if all goes well,
within two to three weeks I will give you the answer
for sure at the first flight I will be terrified.