First Build, Scared motor is damaged...

[Nick]

Hello all, as said in the title I'm doing my first quadcopter build. It's a 450mm frame with 1000kv motors and an Arduino as the flight controller that I'm going to be programming.

Last night I was soldering up one of the motors and ESCs and I connected them up to test which direction it was spinning. I forgot that the bullet connector were touching and as soon as I fire up the motor the ESC bursts into flames (exaggerating a bit). The ESC is trash.

Today, I hooked up a new ESC to the same motor ( careful to separate the bullet connectors this time) and it spins up fine like the other motor I already have mounted to the frame. The motor that was connected to the ESC that blew up smells a little burned but runs fine.

My question is, is it just the smell that stayed behind from the ESC that's in the motor or is the motor damaged and needs replacing.

 

[GJH105775]

Probably just the smell from when it burnt. It should be fine, just check the cables for damage, and make sure you repair it if so. Be sure to check back in a week or so to see if the cable is hard.

Your ESC may be repairable. Cut the heatshrink (if any) off of it, and attach a few pictures. As long as you did not ruin an IC it should be repairable, they have diodes that cause a short circuit to keep it from damaging any electronics past the leads.

 

[Nick]

Thanks for your reply, that makes me feel better. The connections for the motor look good from what I can tell. Unfortunately, I know the ESC is fried because it was one of the ICs that burst into flames. Doesn't look repairable. I have another one on its way in the mail.

If anyone else has another opinion please post but I feel like my motor will be okay. I'll just let it the smell diffuse. Only time in running the motor will tell I guess.

Thanks again.

And as for checking if the cables are hard, the wires to the motor are already pretty stiff because of the model of motor not using very flexible wires so it may be hard to tell.

 

[GJH105775]

Ok, you'll know in a few weeks or so. The short happened outside the motor, so it should not have affected it. If the wires were stiff then you should not have to worry, because what I am talking about only happens to aluminium wires when they get really hot. They become brittle enough to break like toothpicks after they corrode badly. The ESC would be repairable if you felt like SMD soldering a new IC, but being as the IC burnt it is a lot easier to replace the whole ESC.

 

[Nick]

Looking through the bottom of the motor, I can see some black on the coils of wires inside the motor that I don't see on the other motor. Maybe it did get corroded on the inside. Is there any cleaning or soldering I can do to fix this?

 

[GJH105775]

The copper coils won't corrode like the aluminium would. The coils used for motors do however have a thin coating on them that is non conductive. It could be burnt, if the motor runs fine, I'd not worry about it unless it gets unusually hot. If it gets hotter, then one of the wires could be partially burnt through or something similar. I'd run it a little just to see if it acts up. When you first get it into the air just keep it a little lower for a few minutes to see if it wants to fail.

 

[Nick]

Thanks for all the advice. Hopefully I'll have it in the air soon.

 

[GJH105775]

Haha, I wish you luck. The biggest limiting factor for me was that shipments took forever to come in. I started ordering in January, and did not get it in the air until Early this month (March). This was due to ordering the things needed to fly in two separate shipments.

 

[Nick]

Well that's the beauty of Amazon Primes free 2 day shipping. If you're a college student you can sign up for $50 a year for Amazon Prime. If you're not in college it's $100 a year.

 

[holtneil]

Hi Nick if you remove the C clip on the bottom of the motor , the top will lift off you can then see the windings in side and if its a film on the windings that got hot it will rub off , if this does happen I would replace the motor , But Like George said I think it will be ok , some motors do have silicon wire which is more flexible , these are better for multi rotor but they will still be ok for what your building

 

[Nick]

Thanks, I'll try to take it apart and clean it off today.

 

[holtneil]

Hi Nick dont clean it off ,if it is burnt it means the motor had an overload of voltage , and I would then replace the motor ( this is if the film rubs off the windings if it does not the motor will be fine)

 

[Nick]

So are you saying that if the black doesn't rub off of the copper windings then it will be fine?

Pardon my bad pictures.

 

[holtneil]

No they are good photos , well I would say that the motor has had an overload ,I will ask George to look at pics

 

[Nick]

So if it's had an overload but still runs is it okay to keep or do I need to replace it? Sorry I'm a novice to electronics, I'm trying to learn as I build.

 

[holtneil]

If it has and it was me I would replace it ,if it fails in flight the quad will crash if your very high up it will total the quad , Let George take a look I messaged him and asked him too , also another thing to think about is if it is damaged will it put more load on the esc and damage and new one over time , replacing one motor now is not as bad as having to replace all the motors as the burnt one has failed and the other are worn so will not be as powerful as the new one will be ,so to keep quad balanced all motor will have to be replaced

 

[Nick]

Well I'm getting a new ESC and motor in the mail Friday. I'll just replace the motor when I get it So I don't have to worry.

 

[holtneil]

It may be best to I found out a long time back if your not sure of some thing change it , its cost me a few frames not too

 

[Nick]

I'll probably change the motor tonight and then install the new one Friday and have the monster hovering (while tethered) Saturday. Thanks for all the help.

 

[GJH105775]

The wires are coated with an insulation, that keeps them from shorting and protects them from oxidation. It is likely that the motor will loose this pole if you have a hard crash, vibration, or if the resistance causes it to come apart at the thin spot in the coil. If you loose a pole you'd probably have time to land, but it is unlikely you'd notice it until it got hot enough to be bad. It would cause it to slow down (with a load, no load it would be unnoticeable) at the pole that is bad. If there is a much resistance(probably is) this pole would cause the motor to get much hotter than normal, which would cause the motor to become less efficient with power. Being as the motor is damaged like it is, you probably should not use it in the air.

Short answer, I agree with replacing it.