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Old Oct 11, 2012, 07:25 AM
Boats on the brain!!
green-boat's Avatar
Arnold, Mo.
Joined Jul 2005
4,519 Posts
It has been done before, in a way. Bill Zumwalt used a simple transistor (2N3055) and a pot for an ESC. The reverse was done thru a DPDT pushbutton switch. The servo was connected to the linear pot and with a spring override on the pushrod. The trim was moved to activate the pushbutton reversing the motor. So a servo switching a DPDT switch will work.
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Old Oct 11, 2012, 08:01 AM
Tinkerer in Training
RGinCanada's Avatar
Guelph, ON
Joined Sep 2004
1,845 Posts
Quote:
Originally Posted by bgnome View Post
in any case, yes, flopping the wires would "work", but at the very least, I wouldn't slam it into reverse at full throttle.
Quote:
Originally Posted by mfr02 View Post
If fitting an electrical reverser, relay or wiper board, it is important to make sure that the contacts can handle the current, and that there is some form of interlock to ensure that the motor is stopped at changeover.
In normal operation, that wouldn't happen (reverse at speed), but I wonder if it would have a negative effect on either the ESC (A brushless 30A E-Flite is my sacrificial test subject) or the motor (A Hobbyking 1100kV 480 sized outrunner).

I suspect it would act like a brake, quickly slowing the motor, then spinning it in the opposite direction. I'd guesstimate that peak current might be 3X no load for a short time, and I highly doubt the motor in question would draw 10A,

I'll keep you posted
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Old Oct 11, 2012, 03:39 PM
made of fire and pop rocks
bgnome's Avatar
Richmond Virginia
Joined Oct 2009
1,710 Posts
I certainly think it will work with what you have, and the currents and wattages concerend.

bare with me here, it's pushing 20 years since I had to really worry about any of this stuff, but round abouts way of thinking about it is that throwing the thing into reverse, hard wired like that you get into a regenitive braking situation where the motor is turned into a generator, on the industrial scale, that energy is either reclaimed, or blown off as heat. The danger is back feeding current into the ESC and causing the magic smoke to leak out. but I don't think it's that's much of a concern.

hook up your sacraficial lambs and show us the results. Things that go boom, can be just as entertaining as pretty model videos.
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Old Oct 12, 2012, 12:33 AM
Is life for real?
pkboo's Avatar
Almere The Netherlands
Joined Sep 2006
1,320 Posts
Hear, hear!

Quote:
Originally Posted by bgnome View Post
......hook up your sacraficial lambs and show us the results. Things that go boom, can be just as entertaining as pretty model videos.
Yes... one way or the other, totally agree! Boo
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Old Oct 14, 2012, 08:34 PM
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Joined Jul 2008
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Originally Posted by pkboo View Post
Yes... one way or the other, totally agree! Boo
Ha ha yes they can be until its your thing doing the booming.
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