Problems running 2 motors on one please - RC Groups
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Sep 30, 2005, 07:15 PM
Bidule mAV

Problems running 2 motors on one please

HI everyone. I need some help regarding my thesis project. I am building a mini UAV for my thesis. It is powered by 2 Feigao 12x22mm 5250KV Brushless motors. I am running an IPS gearbox, 2S 340mAh Kokam Lipo with a CC Phx 10 controller. The model is now finished but I am having problems with the ESC.

I have been told you can run two motors of the ESC sucessfully. When I open the throttle one motor spins up while the other windmills. Then I close the throttle and the other spins up vice versa. Do I have to change the timing advance or something? Your help would be appreciated.
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Sep 30, 2005, 09:18 PM
Registered User
Experience says that two brushless motors on one ESC will work sometimes but most of the time they won't.

Your setup obviously is one that's not happy and probably the best advice would be to simply stick another ESC in there. I doubt very much if tinkering with settings will help but there may be others out there who know different.

Not the cheapest way around the problem but it will work.

One thing you should check is current draw. I tried my motors separately to find base data to work from and found that, on the few times the pair did run on the one ESC, the current drawn was considerably higher than twice the single motor figure. Both the ESC and the motors got hot quite quickly.

Chris Bromley
Sep 30, 2005, 11:44 PM
Watts your motivation
roccobro's Avatar
I've heard mixed things about the little Feigao's. Manufacturer ( I think) says they will not work off one ESC, others have proved this wrong. It could also be the firmware verison of the ESC. Some of the earlier CC versions had trouble with dual motors and some outrunners.

Definitely check the current draw of one motor as Chris suggests.

Sep 30, 2005, 11:46 PM
stone_axe's Avatar
It's my understanding that 2 BL motors on 1 ESC is not really doable.
Oct 01, 2005, 12:03 AM
Watts your motivation
roccobro's Avatar
The motors just need to be the identically the same. You'd think that production made motors would be identical, but sometimes they are not. The hardest would be making two CD motors that were identically hand wound. But they are done quite regularly now.

Some brand of ESC's just can't do it at all. Castle ESC's have been really good at dual motor synch'ing.

Oct 01, 2005, 06:16 PM
Bidule mAV
I have run one motor on a test rig using a power supply and various gear ratios. The current draw is well withing the ESC. The Feigaos are rated to a max of 2A.

I am using the latest software for the ESC. Maybe I should try an older version?

Thanks everyone for your advise.
Oct 01, 2005, 06:57 PM
Ascended Master
Sparky Paul's Avatar
I would go to two ESCs, with one slaved to the other, with its control on a knob or slider. I used this approach on my twin brushed airplane to investigate the effects of power on asymmetric handling..
I could stop either motor or reduce power to either motor.

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