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Old Oct 28, 2009, 01:49 PM
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San Jose, CA
Joined Sep 2003
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Quad brushless motors and quad ESC wiring

Hi,
I am trying to put 4 of this motors on my C-130 http://www.hobbycity.com/hobbycity/s...idproduct=5358
and 4 of these ESC http://www.hobbycity.com/hobbycity/s...eed_Controller
I tried to search on this forum that in general how others setup with 4 brushless motors with 4 brushless ESC, but no luck.
On my other planes, twin motors, I use Y-harness for receiver wire and parallel adapter for battery wire.
I wonder, what do I have to do with 4 engines and four ESC.
Anyone has any experience with this setup, please share your knowledge.
Thanks alot.
Jason
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Old Oct 28, 2009, 02:08 PM
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East Anglia, UK
Joined Sep 2002
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its a compromise between long battery wires and added capacitors to eliminate instability, or long motor wires, or multiple packs.

I think my way would be to use a smartBEC and a single pack, to ensure that all the motors LVC'ed together, and a central pack location with very fat wires a and something like 2500uF in each nacelle and a local ESC, one per motor.

But there is no single answer to this.
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Old Oct 29, 2009, 12:07 PM
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Westerville, Ohio, USA
Joined Aug 2007
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Forgive what is probably in a FAQ somewhere, but I never did understand the purpose of capacitors. I've had them on brushed motors, but don't see them on brushless (built into the ESC?).

I'm designing my first twin, and have the same questions. Will I need capacitors? How big? Where do you put them? I was planning the long parallel battery lead / short motor wires strategy.

Or...know any good FAQ lists?
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Old Oct 29, 2009, 01:11 PM
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San Jose, CA
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Quote:
Originally Posted by KrazyKyle View Post
Forgive what is probably in a FAQ somewhere, but I never did understand the purpose of capacitors. I've had them on brushed motors, but don't see them on brushless (built into the ESC?).

I'm designing my first twin, and have the same questions. Will I need capacitors? How big? Where do you put them? I was planning the long parallel battery lead / short motor wires strategy.

Or...know any good FAQ lists?
KrazyKyle,
Your twin, is it brushed or brushless? I have my C-130 twin, brushed motors, one ESC. I don't have any capacitor.
I also have a twin brushless as well, 2 brushless motor, 2 ESC, no capacitor either. Both setup run very well so far.
In general, it is better to extend the motor lead than battery lead. Long battery lead will cause damage the ESC.
Hope it helps.
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Old Oct 29, 2009, 04:02 PM
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Blackpool, Great Britain (UK)
Joined Dec 2003
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whatala

This may help: http://www.peterangus.pwp.blueyonder.co.uk/multi_b'less.htm
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Old Oct 29, 2009, 05:25 PM
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San Jose, CA
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Hi Peterangus,
This is very handy and helpful.
Thanks a bunch.
Jason
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Old Oct 30, 2009, 10:53 AM
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Westerville, Ohio, USA
Joined Aug 2007
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I'll be doing brushless. As for the relative length of wires, what's the reasoning behind using long motor leads and short battery leads? Would it be because the current in the motor leads is spread over 3 wires?
I'd be interested in hearing what the EDF guys have to say. A lot of the time the battery and motor are widely separated fore-aft.
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Old Oct 30, 2009, 08:29 PM
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United States, NJ, Frenchtown
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One way IS A LOT easier.

Supposidly we should not extend the ESC's battery leads. Unless we ADD more capaciators ON the ESC board. Not the easiest thing without a learning curve or someone with experience.
Or the other way. Run LONG motor leads. Should never cause a problem.

I am cheap & a chicken. I use brushed motors on 4 engines or more.

Sport, multi engines should be simple ...........1 battery, 1 esc., 4 brushed motors all wired to the 1 ESC.
I love just connecting the battery plug and taking off.
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Old Feb 28, 2010, 08:27 AM
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Ireland, Kildare, Leixlip
Joined May 2002
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Quote:
Originally Posted by vintage1 View Post
its a compromise between long battery wires and added capacitors to eliminate instability, or long motor wires, or multiple packs.

I think my way would be to use a smartBEC and a single pack, to ensure that all the motors LVC'ed together, and a central pack location with very fat wires a and something like 2500uF in each nacelle and a local ESC, one per motor.

But there is no single answer to this.
My Dad's building himself a 72" Sunderland at the moment and I'm trying to come up with a power system for him. I'm estimating an AUW of about 3.6kg. I could use a second opinion on the power system since my experience is mostly single motor aerobatic planes.

I'm leaning towards the following:
4 x Scorpion S-2215-18 motors
4 x Turnigy Plush ESCs
1 x 5800mAh 4s or 6600mAh 3s

Why allow for both 3s and 4s? Because he'd like to use 3 blade props as per the full size but if the chosen setup doesn't perform as exactly as expected there's not much choice in 3 blade prop sizes for tweaking.
The size of plane and the nacelle spacing really only allows 8" props. So I'm planning for 3 blade 8x6 props and 3s battery but with a fall-back position of 2 blade props in the 8x4 to 8x6 range on 4s.
Either way the target is between 750W and 1kW at WOT and I expect it'll cruise at 400W or less, giving approx 8 to 10 minutes of duration with a little left over.

Wiring?

The plan is to put the ESCs in the nacelles with the motors and wire the power and RC cables as shown in my schematic below.
Preference would be to use the motors for yaw control on water and maybe in the air too. This would mean either using two channels for throttle (1 per wing) or using 3 throttle channels so that both inner motors would be connected to the RX with a Y lead and the outer motors on separate channels for yaw control as shown.
Capacitors will presumably be needed on the power cables but I haven't looked what to use or how to wire them yet. How do I go about sizing the capacitors? (will I need an oscillascope?)

Do you see any problems with this plan Vintage?...or anyone else for that matter!
Feel free to let me know if you see any flaws in my overall plan or the schematic.

Thanks for your help,

Aidan
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