Motor starts smoking during first throttle test. Bad motor? or something I did?

[Tanasqui]

First Plane, first build, and when I finally received my battery charger in the mail from half the world away I checked the battery, connected everything and got the tx/rx success beep sequence and touched the throttle (still propless) to test that everything was working and a long tendril of smoke immediately began to rise from the brand new GT2210/11 from the flite test power pack from lazertoys.

What could I have done wrong? Or just faulty part?

 

[Christopher14]

Did you have all three wires from the ESC to the motor connected? Or just two?

 

[adamd]

Do you have a picture of your setup?

 

[joshuabardwell]

It's pretty hard to fry a motor. Did you hook the motor up to the three leads coming from the ESC? If you hook the motor up to a DC power source, you'll fry it, but that would have happened as soon as you plugged in the battery. To me, the fact that it only smoked once you gave it throttle suggests that it was either a bad ESC or a bad motor. The motor may have a short in it, or the ESC may have passed DC voltage to the motor. Most likely cause, IMO, given that all the equipment was fresh from the factory, is a bad motor. It seems to me like a minor defect in the wiring (a nick in the enamel on the wire, for example) is more likely than a defect in the ESC (which is basically just a PCB).

 

[Tanasqui]

Yes, Christopher14, all 3 wireswere connected.
adamd, Image added
joshuabardwell, No dc power source, just the 3s/2200mAh/35S included in the power pack. The ESC was hot to the touch in the 10-15 seconds it took me to hook the battery in and get the smoking motor.

 

[Tanasqui]

Is there a way to test the ESC without putting another motor on it? I dont want to burn up a replacement motor because of a bad esc

 

[Craftydan]

Tanasqui,


Welcome to the forum!


There is.

Basically you connect a current limiter in line. It should allow enough current through to let the ESC boot up and beep the motor, but as you start spinning the motor, since the current is limited, the ESC can't burn out the motor from going stupid.

The limiter?



Go to your local autoparts store and pick up the cheapest *NON-LED* bulb with two easy-to-connect contacts, then wire them in line with the ESC's Red wire (make jumpers for it, if you can).

If the ESC is good, you plug it in, the motor should be beeped form the ESC, and if you slowly advance throttle, the light will be gin to glow . . .and get it bright enough, eventually the ESC will reset, the motor and light will go dead and the ESC will act like you just plugged it in.

If the ESC is bad, as soon as you plug it in, the light will go full bright -- UNPLUG IMMEDIATLY. It shouldn't be able to burn out your motor, but it sure was trying to. Toss it with great vigor

 

[RichB]

The startup beeps actually come from the motor, so I think you have it hooked up properly (also the picture looks good).

Did the motor move or twitch at all when you applied throttle?

Is the motor able to be turned by hand?

 

[makattack]

Hey Dan, that's a great solution to testing esc's. I had seen an article where a guy used a diode inline. Is that not needed?

Here's the article I found:
http://owenduffy.net/blog/?p=411

I haven't reflashed esc's yet, but wanted to be able to test a reflashed esc without a digital/bench power supply.

 

[Tanasqui]

Craftydan, thanks for another fantastic reply.
RichB, It turned a few times correctly, then twitched back and fourth as the motor began to smoke. It does turn freely.

 

[joshuabardwell]

No dc power source, just the 3s/2200mAh/35S included in the power pack.

Just to be pedantic, a battery is a DC power source. Some people don't understand how the ESC works and hook the battery leads directly to the motor. This kills the motor. It's clear from your picture that you didn't do that, though.

 

[quorneng]

My fear is that although it may have been a bad motor there is now a real danger than you have a bad ESC as well!
It depends on the relative sizes of the ESC (30A?) and motor but normally the current to make a motor smoke is likely to overload the ESC as well and 'blow' one or more of its MOSFETs (the bit that does the power switching).

To my mind a motor that has smoked and an ESC that now only makes the motor twitch should be put to one side and replaced. When you have a motor and ESC combination that works you might try the motor again but I wouldn't as you would be putting the working ESC at risk!

 

[Craftydan]

Hey Dan, that's a great solution to testing esc's. I had seen an article where a guy used a diode inline. Is that not needed?

Here's the article I found:
http://owenduffy.net/blog/?p=411

I haven't reflashed esc's yet, but wanted to be able to test a reflashed esc without a digital/bench power supply.

The diode is specifically for testing advanced ESCs being reflashed with a regenerative braking capability, something you wouldn't do for a fixed wing and might be overkill.

Frankly most ROMs these days the regen braking is an option. If you run and test without the option off, you don't need the diode. If you then turn the regen braking option on, there's no need to retest -- the ROM is already properly managing the FETs. Even for the ROMs that you have to compile the ROM to toggle the option, if you built it first "without" and test OK, it's low risk it will fail when you rebuild it "with" and flash . . . and again, "without", you don't need the diode.

In the end, it won't hurt anything to have a bypass diode across the limiter, but in most cases it's unnecessary complication.

 

[joshuabardwell]

something you wouldn't do for a fixed wing

Oh no? Think about it! The ultimate in VTOL capability! Take off straight up and land on your nose, straight down.

 

[William A]

What could I have done wrong?

No chance the mount screw is too long and hitting windings ?

 

[Craftydan]

Oh no? Think about it! The ultimate in VTOL capability! Take off straight up and land on your nose, straight down.

That would be reverse, not regen brake . . . but you have a point about having an advanced ROM drive a FW ESC.

 

[joshuabardwell]

That would be reverse, not regen brake . . . but you have a point about having an advanced ROM drive a FW ESC.

Ah, yes. Good point. I was thinking of these new 3D-capable ESC's that are just now becoming popular. Wouldn't it be neat to put a flying wing into a vertical climb over the landing zone, then power off and let it fall nose-down, then reverse the motor and bring it down slowly to just kiss the ground?

 

[xuzme720]

Ah, yes. Good point. I was thinking of these new 3D-capable ESC's that are just now becoming popular. Wouldn't it be neat to put a flying wing into a vertical climb over the landing zone, then power off and let it fall nose-down, then reverse the motor and bring it down slowly to just kiss the ground?

I think these are done with variable pitch, but with a reversing ESC, the same could be accomplished.

 

[Tanasqui]

WilliamA, I pulled it off the fire wall, and checked the screws, short screws into the housing, long screws into the firewall, didn't get them in to far.

 

[Tanasqui]

WilliamA, I pulled it off the fire wall, and checked the screws, short screws into the housing, long screws into the firewall, didn't get them in to far.