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Old 08-16-2011, 04:27 AM   #5 (permalink)
A.T.
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Join Date: Jul 2008
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Quote:
Originally Posted by jamisonchang View Post
Hi. Hoping someone might be able to help me. I have a trex 500 and have now had two servos just glitch, get hot and seize just while working on the heli on the bench (testing swash movements with copilot 2 in the first case and helicommand in the second). Once I was using an external battery pack and another time, I had the 6s lipo plugged in going to the receiver through a external BEC.
The swash just stops moving and th/ ings get quiet and . . . uh, oh, the servo is hot and then it is dead. What am I doing wrong Thanks
HE-5245MG is a popular and very efficient servo.
Because processor-based servos are attempting to achieve and hold a commanded
position "much" more aggressively than non processor-based servos, component
matching and set-up is very critical.

Jittering (poor RF communication causing servos to hunt), surface binding, too
heavy (too big) control surfaces, insufficient surface travel that causes
binding, etc will all put undue strain on the motor, especially the brush
structure.

If the servo is having trouble just holding the control surface up while
sitting on the ground, and then asked to go to a commanded position repeatedly
can cause overheating. Overheating causes the brushes to fail, or the ciruitry
supplying the current. If there is no binding, the first failure should have pointed to
an issue of this sort, the second surely does.

Any "digital" servo, irrespective of model or brand, asked to hold a position it can not achieve, caused by excessive EPA or binding linkages etc will experience heat build-up and could fail within moments. It is definitely not normal for these servos to fail in this manner, unless you exceeded their design parameters, copy of spec sheet is attached and please also refer:
Digital Servo - Why They Burnout

and more under sub section:
"Servo - Digital & Brushless Servo, Programmers and Software"
which is under:
"Radio Systems, Accessories, Alterations and FAQ." at:
Alan's Hobby, Model & RC FAQ Web Links

Alan T.
Attached Files
File Type: pdf HIT-HS5245MG.pdf (207.5 KB, 237 views)
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