Motor Failure. Advice please

[JT]

 Well the last piece of my FPV equipment, the screen, arrived this morning and I got it set up in a home made shade and mounted on a tripod. I wired everything up and nervously took to the sky from underneath one of my wife';s throws(she wasn';t here when I ';borrowed'; it)) out of the light. It was pretty scary as hearing the sound from the quad doesn';t correspond to what can be seen and this seems to confuse a little, not to mention a stiff sea breeze had got up, lol.
Anyway my maiden FPV lasted less than a minute as suddenly the sound of a spinning quad filled my ears This is the second time a motor has just stopped mid flight, and as you can see on the video the after the crash the motor kept jittering forwards and back, despite disarming as soon as it had crashed(at least the noise of the motor enabled me to locate it easily), it was really hot to the touch but still spins freely and seems fine.
Does anyone have any idea as to what may be causing this? Is it the crius se v2, or (I think more likely but don';t really know much about this stuff) an ESC. I think from the rotation of the quad while it was crashing shows it was the rear left motor and this is the one that was twitching and hot.
The only physical damage to the quad is one of the landing legs has been torn off from the arm and I have spares!

First quadcopter FPV with motor fail and crash.

cheers
Johnny

[DarrenG]

ESCs seem to be the most common point of failure, I had one die on me recently and watched my quad roll and pile into the ground from 30ft  :bang head:

[nub]

a dodgy winding might cause the motor to heat up and fail, would also maybe explain the jittering.

or maybe a dodgy connection to the ESC?

[JT]

Thanks, the thing that makes me think ESC (although as I say I don';t know much/anything about rc stuff) is that the motor was twitching after disarming.This could just be my lack of knowledge though. Are the motors powered at all when the ESCs are disarmed? Or would this twitching indicate the ESC doing something it shouldn';t. The heat may have been caused by the prop blades not being able to move freely as they were stuck in 2 foot long barley.
I have just tried it out on the table having done nothing to it since it crashed and  ran it at full throttle with props on and me holding it down for around a minute with no cutting out or heating on motors or ESCs.

[Biffa]

a dodgy winding might cause the motor to heat up and fail, would also maybe explain the jittering.

This is a high possibility. My FPV build has been scuppered by a brand new motor with a broken winding. I had test flown it and all seemed OK, further tests and the motor was jittering when starting, then wouldn';t start at all until given a help.

IMGA0425

[JT]

 Thanks, I';ll swap the motor for a first thing to try and see what happens, I';m not convinced that';s what it is but it is the thing I do have a spare one of lol.

[JT]

 Well I changed the motor and put two batteries through it so a total of around half an hour and so far so good

[nub]

nice1 hopefully that';s it sorted

[JT]

 I do hope so, its looking good but the expensive bits( gopro and the immersion tx) are staying off it for the next few flights just in case it does go pear shaped again

[JT]

 I don';t have my multimeter to hand(or indeed my quad at the moment)but will try measuring the voltages when I get the chance.  The thing that was confusing me was that the motor was jittering while it was disarmed when the ESC should not have been providing any pulses to move the motor. Is there a voltage on at least one of the ESCs output wires at zero throttle/disarmed, in which case a poor connection/dodgy wire/winding could mimic a pulse and move the motor? It seems to make sense as the lower the throttle goes the longer the pulse time(to spin the motor slower).

I need to read up on ESCs so I stop asking silly quastions :embarrassed

[Chami82923]

Could you give details of your setup? I';m well impressed with the lack of jello in your video. Type of camera, type of motors/props, have they been balanced?

[JT]

Could you give details of your setup? I';m well impressed with the lack of jello in your video. Type of camera, type of motors/props, have they been balanced?

Sure can, its a f450 clone with cheap as 2212 22 1000kv motors and cheap 9x4.7 gemfan props. The props are balanced as well as I can get them. The camera is a gopro hero3 silver. The ';mount'; is simply two pieces of perspex with pieces of earplug foam between them with large elastic bands wrapped around that both hold on the gopro and tension the earplug foam. Its not very pretty but it does work

[rsmith21]

See my dodgy Bullets that caused intermittent crashes, http://youtu.be/7ZTxFSN2cWk