[NSRCA-discussion] Arming Switch

[Richard Lewis]

I was there for this one as well...Cell phone placed on the wing panel and then 
called by another person...ESC went full on and lost it's programming (reset to 
default).

The demonstration I witnessed was done in a controlled manner to prove that it 
was truly the case in a earlier occurence where the cell phone was believed to 
be he culprit...no one believed it could happen until it was demonstrated....
.




________________________________
From: Mark Hunt <flyintexan at att.net>
To: General pattern discussion <nsrca-discussion at lists.nsrca.org>
Sent: Mon, February 13, 2012 9:56:22 AM
Subject: Re: [NSRCA-discussion] Arming Switch


Myself, among others witnessed a speed control (rx off) turn on violently during 
an interesting test in which the pilot showed us what a ringing cell phone can 
do when placed next to an armed speed control.  No, I don't know the brand of 
ESC.

From: Bob Richards <bob at toprudder.com>
To: General pattern discussion <nsrca-discussion at lists.nsrca.org> 
Sent: Monday, February 13, 2012 9:18 AM
Subject: Re: [NSRCA-discussion] Arming Switch

Keith,

My gut instinct is to agree with you on this, but I have to wonder what is the 
possibility that there would be a failure mode where the controller could go 
full throttle without an input from the receiver. For the brushless controllers, 
the micro in the controller must be working properly for the motor to run - 
period - since it has to sense the feedback from the motor and operate the 
outputs in proper phase for the motor to run at all (this would be a different 
discussion if we were talking about *brushed* controllers). The more likely 
failure would be that it applies power to one or more motor wires - not pulsed - 
that would do little more than heat up the motor and burn a winding, but not 
turn the motor over.

Is it possible for the micro think there is a full-throttle input when there 
isn't? Most controllers that I know of will not arm if it powers up with 
anything other than a low-throttle signal from the receiver. It has to sense a 
low-throttle signal that then transitions to something else before it starts the 
motor turning. Is this a possible failure mode for an ESC - I don't know since I 
don't know any specifics of the circuitry or firmware programming of ESCs, but I 
seriously doubt this can happen and if it can, the likelyhood would be extremely 
low.

Of course, not having the battery connected to anything is safe. Safer yet is to 
just stay at home, but we have to decide what is an acceptable risk.

Bob R.


--- On Sun, 2/12/12, Keith Black <tkeithblack at gmail.com> wrote:

>
>
>Dave, you're points are correct, but you're not taking into account a 
>malfunction of the speed controller itself. They have been know to malfunction, 
>so the safest approach, as Earl suggests, is to assume that anytime the battery 
>is connected to the controller the motor may go to full throttle. Until you 
>unplug the battery the thing is hot and dangerous regardless of your fail safe 
>or switches on the transmitter.   
>_______________________________________________ NSRCA-discussion mailing 
>listNSRCA-discussion at lists.nsrca.orghttp://lists.nsrca.org/mailman/listinfo/nsrca-discussion
> 
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