(I wanted to open a new topic for this, so to not get out of topic on my previous threads)
I want to control a brushless motor and making it go on reverse with the touch of a button. Can I use a relay to change the polarity of the esc, when this button is pressed? Also, if I can do that, then how will i hook it up and what kind of relay should i buy?
here is the esc and the motor i use:
Hi,
No you will kill the ESC, those Brushless DC Motors are actually 3phase AC type motors, the ESC converts the DC supply into pulsing DC on the three output leads, the pulsing approximates the 3phase supply and makes the motor rotate.
Speed and direction is accomplished by varying the frequency of the output and the phasing.
The signal control wire on the ESC is the speed/direction control.
As pointed out in the other thread, some ESCs are bidirectional, others work in one direction only.
This explanation may help;
You will have to investigate that situation.
Tom... 
A brushless motor will change direction if you exchange any 2 of the 3 wires connected to it so it may be possible to use a relay to change its direction using this method. Whether it is good idea is another matter entirely
The best solution is to use an ESC designed for the job such as those use by some RC cars
And 3D multirotor aircraft.
Like we said in one of your other threads. BTW there is no problem keeping all this in one thread, it is after all one heroic effort you are investing, and it makes it easier for anyone to follow along. And keeps you from getting asked the same pesky questions again and again.
Using a relay to reverse brushless motor direction by swapping two of the 3 leads is just a bad idea. If you can't make a good argument about why it isn't a bad idea, you have no business playing with it.
a7
Generally a bad idea.
As is using a relay on such a motor. You would be lucky to find a relay rated for the currents involved, let alone a DPDT reversing relay.
If you want to reverse an ESC, you send the correct control signal to it. If it (unlikely) is not designed to reverse, best to go and find one that is designed to reverse.
That's an odd question in view of the fact that drones only have one propeller direction but
change direction of travel using the difference in speed of one axis to the other.
Even if you could reverse the propeller direction it would not make for a flyable drone and
the 40ms + delay of the relay would complicate matters not to mention that you could fry
your ESC by switching the phases on the fly.
Some people would not agree with that
See I try to learn to fly 3D for the first time.. Rip my GoPro - YouTube
No, that will destroy things. You can only switch the wiring with the power to the ESC removed.
This is the same issue with stepper motor drivers - if you reconnect the wires between stepper driver and stepper with the power on, BANG goes the driver.
If you want a reversing ESC, get a reversing ESC.
Yup, it’s a thing for sure, since like many years.
There have been a few designs using pitch control on all four propellers running off one motor, like 4x helicopter pitch mechanisms, but mostly it’s symmetrical props and bidirectional ESC/motor combos.
Ppl fly them FPV, impressive enough, ppl do it LOS which I find impossible to believe even when seen.
a7
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