YEP 150 Strange Momentary Shutdown

[Error401]

Ok, here's my setup:

Logo 550
Scorp 4025-1100 (original version without the ribs on the can)
YEP 150LV
Align 6A BEC
BD 3X running 2 Spektrum DSMX sats
Futaba S9451 cyclics
Futaba (I forget the model) tail

The Logo is grounded from the belt roller in the tail to the motor mount, then to the negative pole on the esc connector. YEP setting is 18 degrees timing and 8KHz. Bec is powered off of a 2S 1350.

I just want to say first off that this setup flies very nice, and since I got it (from another HF member) is quickly became my goto daily flyer. Which is why I'm a bit frustrated at this point.

With the exception of the motor, all of the electronics came out of an ancient T600e and never exhibited the following issue. Also, the esc was not grounded to the extent that this Logo is now.

At random times (only once per flight too) the motor will momentarily cut off, then start spooling back up as if I had flicked the TH switch off then right back on. It seems to go through a shorter spool ramp than if the TH was left on for a couple of seconds, almost like an auto bailout ramp, though the YEP doesn't seem to have a setting for that. When it finally switches back to gov mode (gov store set and optically set), it is not at the programmed head speed, sometimes a little lower, sometimes a little higher. It has happened while inverted, during tic tocs, as well as just hovering and forward flight. Since I learned to auto, I have not had issues managing these shutdowns, but the one when I was in some heavy tic tocs was close. When it happens I come back in, land, TH on for about 10 seconds, the TH off and finish the pack, usually beating the snot out of it just because. I have not had it do it twice in one pack.

One other point about my setup, I used a short extension on the throttle lead with the red wire disabled, so I can easily change settings on the YEP without disconnecting the lead from the FBL controller and messing with YEP lead to get power. I have changed this lead out for a new one, and I thought that had fixed it, but now it's doing it with the replacement too. Other than the throttle, all other flight controls are not affected. I checked the BEC output voltage and it remains fairly constant at 5.7v under load (on the bench).

Any ideas on this would be greatly appreciated.

[dbrc894]

My best guess is that the governor mode setting did not take since you are describing headspeed fluctuating while in flight. I recommend you reprogram governor mode with 80% battery, no blades of course.

[Error401]

Thanks for the reply, but the head speed is governed rather well when it's running. It just blips off, the ramps back up to another head speed the is not exactly what it was. After landing and remaining in throttle hold for 10 seconds or so, it ramps up and governs at the correct head speed (not a complete shutdown, just TH)

[dbrc894]

Sounds scary to me, I would hate to have any shutdown while in flight especially with a 550. Yep's have always been dependable for me but as with any electronic device, you are going to have a bad one now and then. I wouldn't risk the heli for what little that esc cost.

[Error401]

Exactly. All of my other yeps have been solid, from an 18a in a T250 all the way up to a 120HV in a 700. Even this one was solid when it was in a T600. Baffling.

I'm already in the process of changing over the esc to a yep 100LV with a Yep 20a bec and better servos. Hopefully the problem goes away.

[helidude71]

Does the YEP give you an error indication after you landed?
It should give you some beeps and flashing LED if it detects a problem.

[Error401]

No, no beep codes, no error lights.

I believe the issue was related to my bec, the BD 3x and running 2 sats. The Align 6A bec puts out 5.7v, and the guys in the DB section say that 5.5v is absolute min to avoid brownouts. Not much headroom. What I think was happening was that the sats browned out for a couple of frames and fooled the esc into thinking I had blipped throttle hold, resulting in what I described. It was so short that it felt like I had retained control and made me think that it was an esc issue.

I've changed out the esc and the bec since my last post and it has not done it in the 8 flights I've gotten on it. I'm now running a YEP 20A bec set on 6v (6.2v measured), with a YEP 100A esc.

Another interesting thing I noticed since the swap is that both my motor and esc are running cooler. After a 5:30 flight of reasonably hard 3D, the 100A comes down at ~110f, whereas the 150A came down at ~125f. The motor is a lot cooler as well. I guess there is a point of diminishing returns on the size of the esc for a given motor and gearing.

[Bigpops]

I had this happen on my Warp, last time I flew it. That has a YEP 45A.

It just shut down while I was hovering inverted. As soon as the power went, I flipped it back over and the power came back. No soft start or anything like that. No error beeps from the ESC, nothing in the Vbar log.

I'm not sure, but it could also have shut off again as I brought it in to land.

[xavier91]

Hi all,
I know this post is 2 years old but I just experiencing the same issue with a YEP 40A on an OXY3 and the lynx motor.
The motor shuts down then restarts immediatly with a soft start and then the speed seems to be higher and irregular.
I fly with the gov store. No error indication. more than 20 flights without any problem before it happens.
Any idea? Defective esc? Setup error? bec brownouts ?

Xavier.

[Heli.Maniac]

Sounds a lot like a problem I had once with a YGE esc with a partially cut receiver cable. The signal was shorting to the frame and caused irregular running, stuttering and restarts out of nowhere. Once the cable was fixed I never had another problem with it.

[xavier91]

Thanks Heli.Maniac for your reply. I 'm gonna check this cable again but I'm pretty sure it is ok.
Did you have an error code ? (like 5 bips for a signal lost ?)
Xavier.

[Heli.Maniac]

If I remember correctly, I had no error codes and that's why I had a hard time figuring out what was wrong. If you have another ESC that you can use, it would save you some time to test the motor so that you can be sure the problem is not with the motor. When I had my issue, a friend of mine was kind enough to lend me his Kosmik and that saved me a lot of time troubleshooting.

[xavier91]

That's what I'm gonna do. I have a brand new YEP 40, just have to solder the right plugs and program it. And I'll test again.
Keep you posted.
Xavier