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Old Aug 23, 2009, 11:37 AM
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Joel K. Scholz's Avatar
Kingsland, Texas USA
Joined Aug 2000
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Can running too many servos (4) on a speed control and 3s battery, damage the speed c

I am running into something I have never encountered before. I have added a moveable CG system to my Hawkeye utilizing a Dualsky 40 amp speed control. This control has a 3 amp BEC rated for 4 micro servos on a 3s lipoly. I have 3 micro servos and a high torgue servo on the system. When hooked up, the motor refuses to turn and makes a screeching sound. I hook up another speed control ESkY 25 amp control with dual BEC and motor runs normally. I disconnect all servos and use original 40 amp on motor alone. Motor screeches and will not run. I put the same speed control on a different motor and it operates normally? I am afraid to hook up a new 40 amp controller to the setup as I am afraid too many servos could damage the controller. any ideas as to the problem?
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Old Aug 23, 2009, 11:55 AM
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Xpress..'s Avatar
Joined Oct 2007
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High torque servos can draw more current, so theoretically you could be over running the ESCs BESC, causing it to shut down or refuse to work properly.

Use a seperate BEC and you won't have problems
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Old Aug 23, 2009, 11:56 AM
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Joined May 2003
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An ESC will have one or two thermally protected regulator for your servos. If you draw too much, it shuts down until it cools a bit, then it turns back on.

Most likely you haven't broken your ESC with the load, but something else is going on.
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Old Aug 23, 2009, 11:57 AM
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The Northeast Kingdom, Vermont
Joined Jun 2004
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I would not use the built in 3A BEC with that high torque servo for the CG in the mix with three micro servos, that servo for the CG will pull some real current while shifting things, I would think
The issue with the motor screeching and not turning sounds like either a timing issue, or one motor wire connection is bad.
Good luck,
Pete
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Old Aug 23, 2009, 12:00 PM
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Also, potentially you could fry the servo if the loads on the CG mechanism are too great. Hitec has some new digital servos that draw significantly less current than previous models but put out MORE torque
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Old Aug 23, 2009, 01:32 PM
Former Futaba employee
Joined Aug 2006
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Sounds like a motor timing problem?
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Old Aug 23, 2009, 01:47 PM
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Neenah, WI
Joined May 2006
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Motor "screeching" is discussed in following thread:
http://www.rcgroups.com/forums/showt...85#post8731985

See post #1090
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Old Aug 23, 2009, 08:29 PM
Speed cost money.
highflier's Avatar
United States, FL, Marathon
Joined Dec 2002
3,044 Posts
Yes to many servos can damage the ESC. If the ESC has a linear bec the rating or 3 amps is likely to not be with a 11.1 volt battery. More like 2 amps. If you have a switching bec built in then it most likely will handle 3 amps with an voltage you use.

Highflier
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Old Aug 23, 2009, 08:45 PM
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Ron van Sommeren's Avatar
The Netherlands, GE, Nijmegen
Joined Feb 2001
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About BECs, #servos and battery voltage:
http://www.rcgroups.com/forums/showt...2#post11679182

About de-rating controllers and motors, starting at 'for everyone else':
http://www.rcgroups.com/forums/showt...0#post11476940

Vriendelijke groeten Ron
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