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Author Topic: Twin esc really needed ?  (Read 266 times)

Paragon

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Twin esc really needed ?
« on: June 27, 2019, 08:51:06 AM »

Hi all .
Just a quick question.
Is it possible to run 2 brushless motors from 1 esc ?
Struggling for space with a small twin motor model .


Thanks
John
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Subculture

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Re: Twin esc really needed ?
« Reply #1 on: June 27, 2019, 08:53:10 AM »

No. The esc electronically controls the commutation of the motor, so it's one esc per motor with brushless. Try looking for smaller esc's if you're short of space.

Paragon

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Re: Twin esc really needed ?
« Reply #2 on: June 27, 2019, 09:01:18 AM »

Thanks subculture.
Struggling for both weight and space . Donít want to move esc up as stability may be an issue then .
Just wondering if anyone had used 1 esc with 2 brushless motors before with any success , or if it was even possible.


Thanks
John
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Taranis

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Re: Twin esc really needed ?
« Reply #3 on: June 27, 2019, 09:07:27 AM »

As said in practice no. Each motor will require different timings relative to changes in load even with identical motors.
What ESC are you looking to use? there may be alternatives
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ANDY
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Paragon

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Re: Twin esc really needed ?
« Reply #4 on: June 27, 2019, 09:31:51 AM »

Was wanting to run 2 , 2200kv outrunners from 1 turnigy 50 amp marine esc , at 7.4 volts .
Itís not a big issue just wondering if anyone had done it or if it was possible.
Other set ups I have work twin motors twin esc .


John
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malcolmfrary

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Re: Twin esc really needed ?
« Reply #5 on: June 27, 2019, 09:40:39 AM »

It has been done successfully, but with a lot of care.  Link to an example on another forum - https://www.rcgroups.com/forums/showthread.php?2293170-Two-motors-one-ESC-or-two-ESC-s/page4&highlight=2%20brushless


Two smaller ESCs are probably easier to arrange than one large one, and give the potenial benefit of better control if they are on separate channels.
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Subculture

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Re: Twin esc really needed ?
« Reply #6 on: June 27, 2019, 09:54:19 AM »

Size of model, motors and controllers please. Helpful also to know diameter, blade count and pitch of props, and desired speed.

Finding space and weight distribution with a brushless setup should be easier than a brushed setup, but many modellers especially marine modellers over power their models with much larger motors and escís than is necessary often through lack of understanding, and/or because weight is generally less of an issue than for say aeroplanes.

Paragon

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Re: Twin esc really needed ?
« Reply #7 on: June 27, 2019, 10:11:27 AM »

Without getting to technical from what Iíve read it shouldnít be done.
 Motors and esc are listed above .
The motors are reasonably small as brushless motors go . 3 blade 25mm props . Pitch Iím not sure of , would need to check when I get home but Iíve more or less had the question answered .
I have 2 esc so Iíll just make room for both . Iíve always liked to have extra power and not need it rather than the opposite. Handy on a windy day . 
Thanks
John

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Martin [Admin]

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Re: Twin esc really needed ?
« Reply #8 on: June 27, 2019, 10:33:10 AM »


Contrary  to rational thinking.... you can!
( Not sure I would personally and 'your mileage may vary'! )


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Martin [Admin]

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Re: Twin esc really needed ?
« Reply #9 on: June 27, 2019, 10:38:17 AM »


There is a whole topic on here somewhere but can't find it at the moment....


This a search on Utube: 
https://www.youtube.com/results?search_query=two+brushless+motors+one+esc
 
 
 


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Taranis

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Re: Twin esc really needed ?
« Reply #10 on: June 27, 2019, 10:46:29 AM »

Excellent video and great English  :-))
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ANDY
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Paragon

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Re: Twin esc really needed ?
« Reply #11 on: June 27, 2019, 10:51:06 AM »

Thanks Martin.
Theoretically you shouldnít then but you can with identical motors.
The downside of motors cutting out if one stops can be used as a positive. With model boats !
On Sunday I ran this model with twin esc to separate motors. One prop got fouled with weed and stopped, the other motor ran as normal, causing the model to capsize. If both motors had stopped this may not have happened.
Itís maybe worth an experiment!! Lol


Thanks
John
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morley bill 1

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Re: Twin esc really needed ?
« Reply #12 on: June 27, 2019, 11:13:47 AM »

Hi john  would it help space and weight if you ran two shafts from one motor/esc via a split gearbox  bill....
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Paragon

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Re: Twin esc really needed ?
« Reply #13 on: June 27, 2019, 11:19:35 AM »

Yes Bill it could be an option, itís getting a gear box that will handle the revs .
Watching the videos above, I think an issue maybe one esc doesnít allow you to have counter rotational props . The wavelengths will be out .


John
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Subculture

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Re: Twin esc really needed ?
« Reply #14 on: June 27, 2019, 11:29:49 AM »

Your model sounds a bit unstable if losing a prop was enough to cause a capsizing.

I mainly use brushless motors in the smaller 60-150 watt range, as I run smaller models. You could use significantly lower current esc's than the ones you have for your application. I very much doubt you would pull more than a few amps of continuous current, so controllers in the 20-30A range would probably be more than up to the job. If you don't need reverse, then I like to use forwards only esc's which are a fraction of the cost with a much wider range of choice, also significantly smaller as you need less components.

Martin [Admin]

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Re: Twin esc really needed ?
« Reply #15 on: June 27, 2019, 11:31:49 AM »


... "suck it and see!"    ok2

 If you already have the gear, try it out and see if it works for you.  :-))
 
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canabus

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Re: Twin esc really needed ?
« Reply #16 on: June 27, 2019, 11:38:12 AM »

Hobbyking car ESC's(HK-30 or HK-45A) are better with an electric fan on top.
I using a 45Amp in my Sea Hornet(640mm) with a B28-57-15L 750 Watt on 3S .
Canabus
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Paragon

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Re: Twin esc really needed ?
« Reply #17 on: June 27, 2019, 12:31:32 PM »

Subculture itís a combination of things I think , less weight low down using lipos on a model with I high centre of gravity also 2 esc high enough up and a prop stalling . The weed stayed attached to the bottom of the pond !
Iím adding shot ballast and trim tabs but thought I could maybe lose a esc .  The esc and motor came recommended together. But possibly could go for lower amperage.
As Martin has Said Iíll have a play and suck it and see what the outcome is .
Nothing ventured nothing gained I suppose..


Thanks
John

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malcolmfrary

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Re: Twin esc really needed ?
« Reply #18 on: June 27, 2019, 10:20:38 PM »


There is a whole topic on here somewhere but can't find it at the moment....

This a search on Utube: 
https://www.youtube.com/results?search_query=two+brushless+motors+one+esc

A few years ago, on another forum - https://www.rcgroups.com/forums/showthread.php?2293170-Two-motors-one-ESC-or-two-ESC-s/page4&highlight=2%20brushless
with a video of it working.
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