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Old Jan 09, 2013, 03:24 PM
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Joined Jan 2013
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Help!
Noob question with esc and bldc motor

Hi to every one, this is my first post here, I hope i'm posting in the right section.
I'm making a project in which I need to control the BLDC motor speed (of an old hard drive) with a potenciometer using a micro proccesor (Arduino)

I am totally noob with esc and BLDC motors. First question is: What are those three cables in the ESC for? I know two cables are for power supply, 3 for the motor, but in most ESC there is another 3 more cables... What are they for? is for programming? and..Is it necesary to program the esc? I only need a static and continious speed.

Thanks for your answers and sorry for my english I'm from Argentina.

PS: The project I'm making really have nothing to do with RC, it's a Hard Drive POV Clock (youtube is full of videos of that) but I thought this was the right place to answer my questions. Thanks again!
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Old Jan 09, 2013, 03:33 PM
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New Zealand, Canterbury, Christchurch
Joined Dec 2012
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The 3 smaller wires are for connection to a radio receiver or a flight control board. They are how you tell the ESC how fast to spin the motor.

They can also be used to program the ESC with a programming card, but that only really relates to RC.
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Old Jan 09, 2013, 03:50 PM
Out of helis, sanity returning
Tallahassee, FL
Joined Feb 2009
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I never thought about it before, but you could probably use a servo tester to provide the signal to the ESC. The ESC is really just looking for a PWM signal of between 1 and 2 milliseconds, and that's what servo testers put out via a potentiometer.

Wonder if it would work?
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Old Jan 10, 2013, 12:14 PM
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Joined Jan 2013
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Hey, thanks for the answers! Now I have my ideas clearer, specially about the programming. I've just bought an ESC on DX.com.. so now I have to wait to experiment with it.

Thanks Again
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Old Jan 10, 2013, 01:01 PM
LoS sUAS AP/V is not a crime
United States, CA, Grass Valley
Joined Mar 2012
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Without a TX and RX you will need a servo tester to drive the ESC.
DX has some but looks like there all out of stock.
http://dx.com/p/e-sky-ek2-0907-9-pin...icopters-15594

Sorry, I just reread your first post, you can drive it with the Arduino.
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Old Jan 10, 2013, 02:59 PM
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I have one more question!

Using Arduino to send the servo signal... do I need to keep sending and sending the signal all the time? or just one time to set the speed, and then the ESC keep that speed until a new one is set??

Thanks
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Old Jan 10, 2013, 06:55 PM
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I"m pretty sure it's continuous, but you can easily code it to do a single pass and if that doesn't work put it in a loop
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Old Jan 10, 2013, 07:05 PM
Out of helis, sanity returning
Tallahassee, FL
Joined Feb 2009
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Quote:
Originally Posted by monti73 View Post
I have one more question!

Using Arduino to send the servo signal... do I need to keep sending and sending the signal all the time? or just one time to set the speed, and then the ESC keep that speed until a new one is set??

Thanks
A 50hz PWM square wave is what most ESCs are expecting, unless they are flashed and then they can update at 400hz. So yes, you need to send the signal at least 50 times a second.
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