Two Motors One Controller. (Or Not)

[DadHav]

Hey gang, I'm seeing advertisements for planes that require two outrunners and two controllers. Can you run two motors with one controller, or would the inductance sensing circuit, as in a Phoenix, go nuts trying to figure out what you're doing?

C YA

[Roy_Oetting]

Hi, I just read where Don Matlack. He said "running on 1 phoenix 10 controller turning 3x2 props at 23,000 rpm on 8amps with 3cell 1200mah " He has the motors mounted on a toyrus glider and is very happy with the performance. Most people say you have to use two controllers but maybe it depends on the motors and application.
Roy

[DadHav]

Thanks Roy, I'm experiencing something similar I just replaced a 280 6V race motor in my little Kelly glider with one of the single 22.7s and Im getting about 17,000 rpm with the small Graupner folding prop. This is at least a 25 % improvement over what I had and the system is lighter.
Happy Happy

C YA

[LBMiller5]

Theoretically you need one controller per motor. (But theoretically a bumble bee can't fly either!)

I am going to build a matched set of motors and try this theory out sometime in the future. My feeling is that it can work, but only if you have a matched pair of motors running identical props. I know that people are doing this with good results, so it has to be possible. My thought is that if a motor gets out of sync with the controller, it would slow down a little, until it got back into sync with the controller, and then continue to run. It might "Hiccup" a little but it would continue to work.

My concern is if 1 motor had draggy bearings, or a prop with just a little more pitch than the other one, that motor would keep falling in and out of sync with the controller and run a little rough.

I have had my Electrical Engineering degree for 15 years now, and before that I was a Technician for 10 years, but nothing has sparked my curiosity more than these little CD-ROM motors! They are such engineering marvels and so simple at the same time. I fired up my first Double Stack motor a couple days ago, and it blew my Tach off the table! Man what power these little motors put out!

Have fun, and please experiment and let the rest of us know what you find.

Lucien

[instain]

Check out my post in this thread (http://www.gobrushless.com/forum/viewtopic.php?t=191) complete with pictures!

Since BLDC motors are synchronous and when connected in parallel are electrically locked, they don't really present much of a problem running off one controller. As long as the motors are nearly identical and the loads are reasonably similar (like air...). My twin motors on my P-38 have started and ran perfectly together every single time.

Andrew

[broncomech]

I have a set of GBX2 motors 18T delta turning 8040 APC props both running off of one Pheonix-25 on the test stand. hopefully wil get airframe done soon to try them in the air.

[broncomech]

It works in the air just as well as on the test stand. My airframe design has a few bugs to be worked out but the GB motors perform flawlessly, shut down and restart in flight with no restart issues.
If you have got to have a twin I would try the one ESC set up first, just be sure the motors are built identicaly.