Need Suggestions - Slowing Down After 2 Minutes

[rccopter]

My one way bearing failed and I just finished installing the new one. After flying for about two minutes the heli started to slow down severely and I had to land quickly.
I immediately spun the blades manually and everything feels very smooth. The OWB is still working as it should also. The ESC wasn't hot, and the motor didn't seem any hotter than usual (it has always run very hot to the touch). All battery voltages were good.
I then flew again, and after 2 minutes the episode repeated.
The only other thing I did when it was on the bench for repair was lubricate the motor bearings with Tri-Flo. I wonder if I got some excess oil in the motor causing a coil short or excess current draw?

Any suggestions on where to go from here are appreciated.

Thanks.

Rick

[PTcaflyer]

...Was that on different batteries...Could be on the edge of LVC...
OWB would not fail that quickly...How much oil did you put in the motor Brgs.?
PT

[rccopter]

It was the same battery, but it still had 22.5V remaining after the 2nd flight. The battery is fairly new and I am careful not to over discharge and always store it at proper voltage.
I only put a drop on the upper and lower bearing using a syringe. However, sometimes it's difficult to see how much comes out of the tip... I burned out an ESC once due to excessive motor oiling so I try to be careful.

When my OWB went bad the motor had to work very hard, as the bearing was really stuck to the shaft and offered much resistance. I could hardly turn the blades by hand. I am wondering if this overheated the motor and now the motor has a bad winding.



Rick

[newhelliguy]

My friend had the same issue and it turned out to be a bad bearing in the motor drawing way to much current.

[PTcaflyer]

...try running up the motor with a watt meter attached and see how many amps you are pulling...Plank guys always seem to have those ...

[kavic5150]

Thats why Castle ESCs are great. You can always check the log.

[rccopter]

Thanks all. I'll check the motor and current draw, probably this weekend.

Rick

[rccopter]

I ran the motor on the bench (in the vise) and it sounds like it might have a bad bearing. Can the bearings in the Gaui 1500W - KV1100 motor ) part # 855502) be replaced, or would I have to buy a new motor?

Thanks.

Rick

[rccopter]

I just watched a vid about replacing motor bearings. Going that route.

Rick

[rccopter]

Update: I pulled the motor apart and the bearings felt fine. Upon further scrutiny, I found the 61 tooth main gear had several teeth that were partially stripped. Although everything felt smooth when spinning by hand, it apparently caused enough friction at high speed to overload the ESC. I have flown one pack so far with the new main gear with no issues. Just wanted to pass this info along.


Rick

[Guzziman]

great to hear you got it sorted.I have had my Gaui 550 for awhile now and i always check my owb before flying.Other than that its just check and tighten everything once a week.Have not had any real problems at all.For a nice relaxing Sunday afternoon cruising around the sky this Heli is nearly perfect.Easy to fly and easy to maintain.