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Author Topic: Equivalent brushless motor for a 540 ?  (Read 6737 times)

gwa84

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Equivalent brushless motor for a 540 ?
« on: November 23, 2010, 11:30:46 AM »

hi all ime looking for a brushless motor of the equivalent to a 540 rushed motor and speed controller with a but more umpff its to go in a Kayosho Jetstreem ime hoping to run it of standard 7.2 buggy packs but I'm an absolute noob when it comes to brushless so have no idea cheaper is better for me at the moment so any suggestions please thanks all  :-))
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TomTheKraut

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Re: aqivelent 540 brushless
« Reply #1 on: November 23, 2010, 12:09:53 PM »

G'day,
... a 540 type motor in a Jetstream? That won't give you much fun, methinks. Even if it is "only" the Jetstream-800.

If you want to use Buggy "sixpacks", I would go for a Speed 700 BB Turbo 9.6V http://www.graupner.de/en/products/3308/product.aspx and run that on two of your sixpacks (= 12V) - the according ESC thrown into the package, obviously. This would be adequate to the old "Mono2 restricted" class - and these boats really were fun.

If you insist on going brushless, look for a 600 long-casing type motor of the "inrunner" type which returns about 18000 to 21000 rpm at 12V (nominal, which is in "idle" condition) - when using a Graupner K-series prop about 39mm to 42mm diameter, this should result in approximately 15000 - 18000 rpm under load.
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gwa84

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Re: aqivelent 540 brushless
« Reply #2 on: November 23, 2010, 04:53:09 PM »

thanks for the info much apreciated :-))
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roycv

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Re: aqivelent 540 brushless
« Reply #3 on: December 14, 2010, 03:57:42 PM »

Hi why not try an EMAX brushless outrunner motor CF2812.  I am using a CF2822, which is very similar.

It has a back mounting and being an outrunner the casing spins.
They are very light about 60 gramms, i/p volts 6 -18v up to 16 amps continuous rating.  A forward only esc is very cheap and light in weight.
I replaced a good 540 motor with one of these and it worked very well as well as being much lighter and handling a  much higher power output.

To have a look, get on ebay, put up brushless motors and you will see this one straight away.  7.90p including postage.
hope this helps, Roy
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TomTheKraut

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Re: aqivelent 540 brushless
« Reply #4 on: December 16, 2010, 10:17:51 AM »

G'day,
... I suspect that brushless outrunners don't give enough rpm.
In this specific case the suggested motor is too small by one size (sorry roycv) and rather likely will end in a smokescreen.
In order to make a hull of this size move in a way that is appropriate to the species, one has to look into motors of 700 size (brushed) or 600 size (brushless).
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HS93 (RIP)

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Re: aqivelent 540 brushless
« Reply #5 on: December 16, 2010, 10:26:23 AM »

hey Roy what's your u-tube name so we can find it.

Peter

and Merry Christmas to you Roy
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nick_75au

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Re: Equivalent brushless motor for a 540 ?
« Reply #6 on: December 17, 2010, 09:12:51 AM »

Heli and EDF  outrunners can be up to 5000 Kv :-))

A 27 turn (what calld stock in buggy terms) is around the 2100 Kv, any motor (in or out-runner) around that Kv and capable of handling 20 amps (150 watts) will be close to equivalent. Feigao and other manufacturers do a range of motors that are a direct replacement, a 540-12L is a direct replacement for a 27 turn 540.

Cheers
Nick
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TomTheKraut

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Re: Equivalent brushless motor for a 540 ?
« Reply #7 on: December 17, 2010, 01:49:55 PM »

Thanks Nick, didn't realize that outrunners with the comparatively high inertia of the rotating mass do go that high in rpm.

In Helis they run on gearboxes, right?
When running a boat prop on these figures, all you will have is cavitation - after all, water can not be scaled down.
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roycv

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Re: Equivalent brushless motor for a 540 ?
« Reply #8 on: December 17, 2010, 02:44:33 PM »

HS93, Hi Peter, I have just been on ebay, looking for the brushless motors.  RC-Timer is a good site similar motor 2812-14 4.90 with free postage.  I think the 14 is the number of poles. There seem lots to choose from but be careful of p&p.

Hi tomthekraut how much power in watts is required?  This is the spec of a motor at 5.90 free p&p.

Model No.: 2822-14
KV: 1200KV
Weight: 50g
Motor Dimensions: 28.7*31.5mm
Shaft Size: 3.17mm
Prop/Recom: 8x3.8/8x4
Battery: 2-3Li-Po
Idle current: 0.8A
Load current: 18A
Power (Watt): 300watt
ESC(A): 20A
Ri: 0.118
Pull (Approx): 950g

I know they get hot but it does not seem to bother the one I use.  Not sure how you would cool an outrunner  though unless you put a fan on it.

Merry Christmas all, Roy

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gwa84

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Re: Equivalent brushless motor for a 540 ?
« Reply #9 on: December 18, 2010, 09:59:44 AM »

thanks for all the input guys giving me lots of food for thought :-))
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