Bad ESC?

[Mostly Harmless]

My recently-completed Storch has been experiencing intermittent problems. In the middle of a flight -- after a few minutes -- the motor would cut off and leave me with a dead-stick landing (the radio and servos still worked). Returning to the flight line, the motor will then beep twice (as if power was just restored) and work again. Running tests on the bench showed that the motor was getting very hot, but the current draw (21 amps) was not over what the ESC was rated for (30 a). Equipped with the following:

Motor: NTM Propdrive 28-26 https://www.hobbyking.com/hobbyking/store/__21478__NTM_Prop_Drive_28_26_1000KV_235W.html

ESC: Turnigy Multistar 30a https://www.hobbyking.com/hobbyking...ar_30_Amp_Multi_rotor_Brushless_ESC_2_4S.html

Battery: 3S 2100 mAh lipo

Prop: 10x4.5

Since the prop is a tad big for this motor, I figured I was just over-working it (causing some fault that the ESC didn't like, cutting it off). Thus, I opted for a new motor (Turnigy D3530/14) -- plenty of capability for a 10x4.5, but still within the capabilities of the ESC.


Running up the new motor w/prop on the bench, I noticed it seeming to overheat after less than a minute or so -- and then suddenly cut off (just like with the other motor). After the 2 beeps and starting over, I found that tapping/squeezing the ESC would cause the cut-off and reset.

First of all, the motor should not be overheating after less than a minute at mixes between half and full throttle. Second, moving or otherwise manipulating the ESC should not cause it to cut off.

Has anyone else seen this sort of behavior? I'm new to electrics, but I just have to think I've got a faulty ESC based on the above.

 

[RichB]

It's possible that you have a faulty ESC. it's also possible that your low-voltage cutoff is set too high, or your battery is bad, dropping voltage under load.

If you can induce the cutoff by mechanical manipulation reliably, then maybe you have a bad solder joint or something. I suggest you peel the ESC and inspect it.

 

[Mostly Harmless]

The battery is fresh,and the same behavior happens on a different battery as well. And the low-voltage cut-off shouldn't make the motor overheat.

Pealing the ESC was my first impulse -- nothing obvious from visual inspection. Given the small circuits, however, I doubt I'd be able to see anything that would stand out. Because I can't trust the components, replacing them is the best option. With the motor replaced, I'll just have to try a new ESC.

Grrrr, more delays before I can fly, again...

 

[xuzme720]

It sounds like an ESC issue. Squeezing making it fault is a bad sign and I would not trust it.

 

[Tritium]

Probably a cold solder joint somewhere on the ESC! Get another!

Thurmond