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Old Jun 16, 2009, 11:28 AM
Isaiah 40:31
Atlanta, GA
Joined Dec 2008
88 Posts
Question
Motor wont hold full throttle

I just finished building a mini telemaster and I'm pretty new to the hobby and when I put the throttle on full it only holds it for a few seconds before stopping. It doesn't do this on slower speeds. Is this something with the speed controller? Any suggestions?
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Old Jun 16, 2009, 11:40 AM
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Mark Wood's Avatar
United States, CA, Bear Valley Springs
Joined Feb 2000
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Ensure the battery is fully charged and try again.

mw
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Old Jun 16, 2009, 11:51 AM
Deletedfor proving Nauga wrong
Joined Mar 2005
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Possibly too much current demand and the resistance ofthe battery causing the voltage at the ESC to "sag" enough to trigger the low voltage cutoff.

Possibly your setup has enough servo load to cause the ESC to trip off the motor due to a thermal protection system. High power will cause higher servo power demand (even durring "static" tests)
If unplugging one servo cures it... you need to disable the ESC's BEC and use a different power supply to the RX.
You can also test for this by just moving the sticks rapidly and checking for the ESC getting hot.

Occasionally you can get a thermal ESC shutdown by demanding too much current for the motor.
If the ESC is hot when it shuts down you should consider using a lower pitch and/or smaller diameter prop.

***************************

You either have an undercharged battery or you are overloading something.
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Old Jun 16, 2009, 12:18 PM
Isaiah 40:31
Atlanta, GA
Joined Dec 2008
88 Posts
I just charged the battery last night so I'll see what happens with the essc later.
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Old Jun 16, 2009, 04:19 PM
Isaiah 40:31
Atlanta, GA
Joined Dec 2008
88 Posts
like I said earlier, I'm a beginner and I get the general idea, but how would I use a different power supply for the Rx and how do I disable the BEC?
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Old Jun 16, 2009, 04:36 PM
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to disable BEC you simply clip the center (+) wire of the 3 wire lead between ESC and RX. I clip the center lead of an extension thus making it very simple to go back.

Then you either get an appropriate RX battery (typically 4 cell AA NiCd or 5 cell AA NiCd.... or NiMh)or you get a stand alone BEC/voltage regulator (often called a "UBEC"... but thats a brand name.. Kind of like commonly calling facial tissues "Kleenex")

The new RX power source is plugged into any unused RX channel (servo slot) or you can use a Y harness to plug it in AND plug a servo or other device (ESC) in the same channel.
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Old Jun 16, 2009, 04:53 PM
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Xpress..'s Avatar
Joined Oct 2007
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Mini Telemaster is small enough to where you can use the ECS's BEC without problems. I wouldn't disable it, and save yourself some weight (adding a seperate RX pack adds on weight and increases the flight speed, making it come in faster for landing- also make it less stable).
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Old Jun 16, 2009, 05:19 PM
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But... temporarilly using a separate RX pack is a valid troubleshooting technique. (making that modified "servo" extension a useful thing to have.)

If that cures it... something is probably making a servo draw too much power... find which one.

If that doesn't cure it then you have isolated it to something to do with the ESC/motor/battery/prop system.
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Old Jun 16, 2009, 06:49 PM
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San Francisco Area, CA
Joined Jan 2008
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Whats your power setup?
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Old Jun 16, 2009, 08:57 PM
Isaiah 40:31
Atlanta, GA
Joined Dec 2008
88 Posts
an atlas 12 amp esc, a X-cell 7 cell 1100 mah sport Nimh battery and an 8*6 prop.
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Old Jun 16, 2009, 10:38 PM
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Which motor?
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Old Jun 17, 2009, 08:04 AM
Isaiah 40:31
Atlanta, GA
Joined Dec 2008
88 Posts
An axi silver 2208/34 brushless outrunner.

would an extra cooling duct help, or would it make to small of a difference to be worth while?
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Old Jun 17, 2009, 08:18 AM
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53859 Niederkassel, Germany
Joined Sep 2000
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An 8x6 prop is "borderline" for your drive setup. Recommend to use an APC-E 8x4" and try again.

Jürgen
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Old Jun 17, 2009, 09:59 AM
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Quote:
Originally Posted by Jurgen Heilig
An 8x6 prop is "borderline" for your drive setup. Recommend to use an APC-E 8x4" and try again.

Jürgen
We have a winner...

Yep

Drawing too much power with the motor due to excess prop load
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Old Jun 17, 2009, 01:54 PM
Isaiah 40:31
Atlanta, GA
Joined Dec 2008
88 Posts
thanks you guys rock, well I'll head to my LHS, get the new prop, and hopefully get this bird in the air soon thanks!
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