RCU Forums - View Single Post - Arming switch

04-09-2013 | 01:04 PM

#26

Silent-AV8R

Joined: Mar 2004

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From: Orange County, CA

RE: Arming switch - advice.

Quote:

ORIGINAL: smcharg

Quote:

ORIGINAL: Silent-AV8R

I'd be all for that if it allowed for the use of the Emcotec Safety Power Switch.

I love the look of the Emcotec and actually spent some time on the phone trying to get them to understand our (Pattern) needs a little better. The problem with the Emcotec is that if it does fail, it fails closed which means there is still power to the electrical components. They fail it closed because of BEC. Most guys in pattern don't use BEC at all and therefore, need this to fail open. I explained the problem and they said they understood and would consider making an ''F3A'' version but that was almost 9 months ago. I would love for them to design something for our needs. It really is nice albeit quite heavy in comparison to some of the others. The other problem with it (as mentioned to the engineer in Germany) is that all of the Emcotec is still based on electronics. There never is a physical disconnect between the battery and ESC.
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It is true that once it is on, if it fails it stays on. But I also spent some time with them and found out that if it is off and fails, it will not turn on or otherwise complete the circuit unless there is a hard short in it, which they have never seen. I'll keep using them until the rule is changed. If it is changed I cannot understand why this device would be deemed unacceptable.

If my plane is sitting in the pits two failures need to happen. One would be a hard short in the Emcotec switch to allow power to the battery. Any other kind of failure and it will not turn on.

Then, I would also need to have my ESC fail, since it will not arm if it does not see a radio signal. But let's say the radio is on for some reason.

Then after both the Emcotec switch AND the ESC failing I would also have to have the master switch (switch) on AND have the throttle kill off (slider) AND the throttle stick would have to be off idle before the prop would turn. That seems pretty safe to me.

Of course I suppose you could argue that if the ESC fails then it might arm without the radio signal. But that still requires TWO simultaneous failures.

The only thing the Emcotec will not do is turn off in the air if it fails while ON.

Here is the last email I got from them:

Quote:

Dear Bill

1) If plane is flying what happens if the SPS unit stops working correctly? Will power still be connected to the motor from the battery??

It depends on what get broken, this we will not know. If the MosFet gets open then it will turn off, if it makes a short circuit then it stays on.

2) Is there any way that once the battery is connected to the SPS and prior to removing the magnetic plug that something can happen to the SPS unit that will result in power be passed to the ESC/motor?

If there is not a short, then if you not swich on it will stay off.

Ich hoffe, ich konnte Ihnen behilflich sein und verbleibe mit freundlichen Grüßen

Dipl. Ing. (FH) Andreas Peukert

Entwicklung Elektronik / Support

==========================================
EMCOTEC GmbH
embedded controller technologies
Waldstr. 21
D - 86517 Wehringen
Tel. +49 (0) 8234 / 95 98 950
Fax +49 (0) 8234 / 95 98 959
www.emcotec.de
www.rc-electronic.com

Handelsregister Augsburg: HRB 16761
Geschäftsführer: Robert Hussmann
USt.Id.-Nr.: DE 198591085
==========================================

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