Driving Outrunner usingone ESC

[gpsnuts]

HI ,

I wonder if anyone tried driving two motors using one ESC? Of cause the ESC has juice to satisfy two motors.

[chessgame]

well, everything is possible.

U can do this, just watch the wires that you use to connect the esc to motor can take the amp draw.
the normal 3mm ones can take up to 60 amp without too much complications.

Interesting to see how you do this and while i have a few ideas, i think most people dont do this because we want to have ability to change motor and esc easily.

[Crafter]

Depends on motor/esc type

HI ,

I wonder if anyone tried driving two motors using one ESC? Of cause the ESC has juice to satisfy two motors.

Hi gpsnuts,

You were not specific about the type of motor and ESC in question here.

You may already know this, but in case you or other readers are not aware, there are two types of electric motors these days, Brushed-DC motors and Brushless-DC motors. The ESCs to drive these two types of motors also operate differently. So there are also Brushed ESCs and Brushless ESCs.

Brushed-DC motors mainly have 2 wires, a +ve and a -ve. Similarly, a Brushed ESC will also have a +ve and -ve wire that connects to a Brushed DC motor.

A Brushless-DC motor usually has 3 wires, and a Brushless ESC also has 3 output wires that connect to the 3 wires of the motor.

To cut the technical descriptions short, a brushed-DC motor changes the magnetic field polarity in the motor (commutates) by changing the connections to the motor winding through the brushes(contacts) inside as the motor spins.

A Brushless-DC motor, as the name implies, does not have brushes, and relies on an external 'switching' circuit to shift the magnetic fields in the motor, to cause it to spin. That external circuit is the Brushless ESC, which performs the commutation for the motor.

From the above, you can see that the 2 types of motor operate differently. Hence you CANNOT use a Brushless-DC motor with a Brushed-DC ESC, NOR wise versa.

Driving two or more motors with one ESC
Now back to your question. You CAN connect 2 or more BRUSHED-DC motors to the output of a BRUSHED-DC ESC, provided as you mentioned, that the ESC has sufficient output current capacity (juice as you say)to meet the needs of all the parallel-connected motors.

As for driving 2 or more Brushless-DC motors using 1 Brushless-DC ESC, I afraid you CANNOT do that, as far as I know. Each Brushless-DC motor will require its own Brushless-DC ESC to drive it. It's nothing the do with current capacity, just that each motor requires its own dedicated commutating circuit to work properly, so they can't share ESCs with other Brushless motors.

I hope with the above info, you can derive the answer to your question.

Others, do correct me if I'm wrong.

Cheers and happy flying!

[Babylon5]

Hi gpsnuts,

You were not specific about the type of motor and ESC in question here.

You may already know this, but in case you or other readers are not aware, there are two types of electric motors these days, Brushed-DC motors and Brushless-DC motors. The ESCs to drive these two types of motors also operate differently. So there are also Brushed ESCs and Brushless ESCs.

Brushed-DC motors mainly have 2 wires, a +ve and a -ve. Similarly, a Brushed ESC will also have a +ve and -ve wire that connects to a Brushed DC motor.

A Brushless-DC motor usually has 3 wires, and a Brushless ESC also has 3 output wires that connect to the 3 wires of the motor.




To cut the technical descriptions short, a brushed-DC motor changes the magnetic field polarity in the motor (commutates) by changing the connections to the motor winding through the brushes(contacts) inside as the motor spins.

A Brushless-DC motor, as the name implies, does not have brushes, and relies on an external 'switching' circuit to shift the magnetic fields in the motor, to cause it to spin. That external circuit is the Brushless ESC, which performs the commutation for the motor.

From the above, you can see that the 2 types of motor operate differently. Hence you CANNOT use a Brushless-DC motor with a Brushed-DC ESC, NOR wise versa.

Driving two or more motors with one ESC
Now back to your question. You CAN connect 2 or more BRUSHED-DC motors to the output of a BRUSHED-DC ESC, provided as you mentioned, that the ESC has sufficient output current capacity (juice as you say)to meet the needs of all the parallel-connected motors.

As for driving 2 or more Brushless-DC motors using 1 Brushless-DC ESC, I afraid you CANNOT do that, as far as I know. Each Brushless-DC motor will require its own Brushless-DC ESC to drive it. It's nothing the do with current capacity, just that each motor requires its own dedicated commutating circuit to work properly, so they can't share ESCs with other Brushless motors.

I hope with the above info, you can derive the answer to your question.

Others, do correct me if I'm wrong.

Cheers and happy flying!

Hi Crafter, his first Thread title already say mention " outrunner" .(Outrunner motor=brushless motor but Brushless motor is not necessary ourunner but can be inrunner)
I don't thing (to the best of my Knowledge) that there is brushed or DC outrunner motor.

So His question is whether possible to drive a twin outrunner motor using a single brushless ESC.

Personally I have not try it but theorectically possible but they maybe problems associated if the two brushless motor are not identical although maybe the same type. That because of tolerances in the windings.
Just my 2 cents

Cheers

[gpsnuts]

HI Crafter,

Thanks for the lenghty reply. I should have more specific; I was refering to BL motors. I am not familer with the operation of the BL motor, so I rely on the expert to help out here. It seems that thee is no safe way to operate 2 or more BL motors with one ESC. I still believe there is a remote possibility if I could figure out how the motor is wound. The motivation is to save some weight and possibly cost.

Thanks

[Babylon5]

One ESC to multiple brushless motor setup problem

Here is the link to problem associated with one ESC to multiple brushless motor setup

http://www.rcgroups.com/forums/showthread.php?t=367827

see thread#12

Cheers

[chessgame]

http://m-a-e.com/Sub_Pages/Products/products_Mots.htm

-A-E Twin Brushless CD-ROM Direct Drive Outrunner Motors
Pre-wired (plug-and-fly) for twin-power applications. Male Deans 3-pin micro connector is already installed. Mating female Deans is provided for your ESC. Motors have same spec's as our 25T M-A-E listed below. Recommend 9x5 props on 2S or 8x4 props on 3S. Generates 16-21 ounces of thrust and weighs just 38 grams! Run these setups on a single 9-10A ESC (see below) Requires two 3.0mm Prop Saver or Adapter

[aeromech]

bros,

actually its possible if the winding of your motor is the star winding ("y" winding) where the winding or ABC are connected to a parrallel point then the other end to the esc as long as the esc can handle the amp draw of the two motors. . .

if your doing this just to save weight is actually not practical for the following reasons:

example 1
motor A is a 2836 1000kv 20amp 40g
motor B is a 2826 1000kv 20amp 40g

ESC A is a 50amp 65g

total weight of 145g

example 2

motor A is a 2836 1000kv 20amp 40g
motor B is a 2826 1000kv 20amp 40g

ESC A is a 25amp 40g
ESC A is a 25amp 40g

total weight of 160g

does 15 grams difference of the two setup a big weight loss already?

there are more ways for you to save weight

example
1. try to compute the amp draw of your setup and change it to the appropriate AWG(thickness of the wire) of your connection wires from battery to esc
2. if your electrical components are fixed for that said plane then try to remove the deans, bullet plugs and then solder them directly
3. try to put all your components as near as possible to each other so that you would have shorter wirings
4. try to see how much flying time do you need so you can also lower down the mah of your battery (lower mah means lighter and more mah means more weight)
5. on my f3p planes all my rx and esc and motor are all modified to save more weight (i did remove the hard casing or shrink wrap of my rx and moded the heatsink and removed shrink wrap of my esc)
6. try to diet your planes weight also by using thin CA and only use Epoxy when needed like the firewall
7. i have alot more in my mind and things i have done also but cant type it all here my finger is in pain already

[Crafter]

More theory...

Hi All,

Haha, interesting discussion :>

I did notice this thread started with "outrunner" in it, which usually meant brushless motors. As far as I've read magazine articles on multi-brushless motor setups, never once was it indicated that all the motors could be driven by one ESC, not even twin brushless setups. So I was hoping the enquirer could arrive at the answer after reading my story.

I believe the reason for this, which I left out of my already lengthy description, is that a brushless ESC not only just commutates the fields for the motor blindly, but actually senses the 'back-emf' in the not-energized windings in the motor, so that the ESC 'knows' which motor winding to energize next, and at what rate. Since the ESC has to sense the 'position' of the motor it's driving, putting a second, third, etc motor on the ESC's output would only interfere with the sensing. Unless of course, in theory, the other motors are in the same 'position' as the first, and are very matching, and react the same. In real-life situations it may not be so easy to have such a closely-matched setup. I understand that the earliest brushless ESCs (and brushless motors) had an additional feedback connection just for sensing the motor's position. With advances, ESC manufacturers now incorporate 'back-emf' sensing to determine motor position, so both motors and ESCs have done away with the feedback connector.

In view of this, personally, I would not try to drive mutliple brushlesss motors with a single ESC. From some links here, it seems some have managed to get away with it. I guess the adventurous among can try it, but don't be surprised if the setup doesn't run smoothly....

I wonder how the MAE twin setup is like.....

Well, just my 1.5cents worth. Hehe. Interesting how stuff works, eh?

Cheers!

[DirtyBoy]

one of the most FAQs about brushless motors..
'Crafter' is right. THEORATICALLY it is possible but PRACTICALLY it is not so simple.. for multiple motors to run off a single ESC they need to be perfectly matched.. and even then they may not start properly..

Here's a good article i came across a few months ago. Open the issue no.3 (March 2006) .pdf file, and in there is a detailed article on running multiple motors off a single ESC

https://www.castlecreations.com/media/castle-scribe.html

Hope this helps..

[Crafter]

Useful info

Hi DirtyBoy,

Thanks for the link to the newsletter. That article about multi-brushless motor setup advise is an eye-opener to me too, especially the programming features and settings of ESCs especially important for multi-motor setups.

Cheers!