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Old Aug 04, 2004, 02:41 PM
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Chandler, AZ, USA
Joined May 2001
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2 Brushless motors on one ESC?

I am sure this has been asked before, but I could not locate it in a search.

Could I run 2 CDROM type 10A motors from one PHX 25 controller? If so, I assume the motors would be hooked up identical wires in parallel.
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Old Aug 04, 2004, 03:25 PM
Schumacher USA
Tampa FL
Joined Jul 2000
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Will not work. One ESC per motor in brushless.

Shawn
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Old Aug 04, 2004, 04:16 PM
myk
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Lake Sawyer, Washington
Joined Jul 2003
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Quote:
Originally Posted by Shawn Palmer
Will not work. One ESC per motor in brushless.

Shawn
I think Shawn's answer is the "Right" answer from the Mfg, however the "Real" answer is that it may work and has many times, there are many reports of your setup working on the forums, however you will probably void your warranty in the process.

Mike
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Old Aug 04, 2004, 05:56 PM
Schumacher USA
Tampa FL
Joined Jul 2000
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Well, ok - let me explain in more detail what happens when it does appear to "work"

The controller is looking for back emf from a single motor. When it gets two signals, it averages them together to decide how to run "the one motor" it sees. The result is, since no two motors are electrically and magnetically identical (nor Kv identical) the controller runs neither motor entirely accurately. Innacurate running means extra amps for the same rpms, and extra heat on the motor, and a general degredation of performance compared to a single motor. It also reduces the amp capacity of the controller, due to the extra heat that is generated on the controller itself (I don't know why this is - that's one for Patrick to answer).

Will it harm motors doing it? Will it harm the controller doing it? That depends on how close you are to the amp specs of the motors and controller, how "different" the motors are, and a host of other things, but the very real possibility exists for one or all three to be damaged, where there is none for two single motors and controllers.

Think of it this way - if it was totally OK to run twins on our controllers - we'd be advertising the poopie out of it as an industry leading accomplishment! LOL (only one controller claims that now, and with a lot of specific stipulations). And I only throw that out there to quell the folks that may say "they just want to sell more controllers". Take it from someone who knows better - not a good idea.

Shawn
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Old Aug 05, 2004, 12:31 AM
myk
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Even though you might blow something up, check out these videos, they are awesome, I just might have to try this some day. First is a twin counter rotating CD-Rom by skirtz that is running on a single Phoenix 25

http://skirtz.rchomepage.com/twin01.wmv

Second is also a twin counter rotating CD-Rom by EljimbO that is running on a single Phoenix 10

http://home.comcast.net/~eljimb0//MVC-610W.MPG

Here are the links to the corresponding threads these are from

http://www.rcgroups.com/forums/showthread.php?t=253610

http://www.rcgroups.com/forums/showthread.php?t=246407

Oh and sorry Shawn for endorsing this (well sort of) but it is just too cool even if your controllers don't "officially" do this.

Mike
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