flyrotary@lancaironline.net Mailing List Archive

Hey, Joe

Get better and worry only about getting that project done

. You and everyone is certainly welcome to state their viewpoint on this list - don't know of anyone banned as yet. While all viewpoints are subject to debate and counter arguments - that's the value of this list.

More than one viewpoint gets presented and no one arbitrarily decides when there has been sufficient discussion - but us guys on the list. When we get tired of it - no one is going to comment further and you end up debating with yourself. But, that's about the extent of anyone getting "banned".

So never hesitate to throw in your 0.02, it may be the one that saves somebody's butt - I was not aware that a MOV could fail closed - I thought once the magic smoke went that it did no more conducting (or anything else) but opened up.

----- Original Message -----

From: Joe Ewen

To: Rotary motors in aircraft

Sent: Monday, March 12, 2007 5:12 PM

Subject: [FlyRotary] Re: A solution? was : The truth??? / Injector flow rate mystery solved

My original thoughts regarding a dropping resistor were the result of being bored while lying in bed with a 102 degree fever, otherwise I would have likely been working on my airplane. In the end, I believe Tracy is likely the best person to devise the ultimate solution. But in fairness to Tracy, he seems to be a rather busy person juggling his manufacturing, airplane building, technical support, and product development may not leave much time to work on this particular issue. So I threw my 2 cents into the ring. My first though was an RC circuit, but thought it may not be a reasonable solution due to its Time/Decay rates.

Last point I would like to make is anyone considering using a MOV "Please read the following info:"

http://www.iaei.org/subscriber/magazine/04_b/04_b_brown.htm

Like any solid state device an MOV is subject to degradation (quickly if the power through it is greater than its heat dissipation capacity). Further, unlike many other solid state devices that fail in the off state when they loose their internal smoke - a MOV can fail in the ON state.

Sincerely,

Joe (Hoping I have not offended anyone, or be banned from FlyRotary like so many others have been from the other list.)
----- Original Message -----

From: marv@lancair.net

To: Rotary motors in aircraft

Sent: Sunday, March 11, 2007 2:30 PM

Subject: [FlyRotary] Re: A solution? was : The truth??? / Injector flow rate mystery solved

What about MOV's? Typical transient response time measured in nanoseconds...

<Marv>

"Steven Boese" <sboese@uwyo.edu> wrote:

Ed and Joe,

The diode in the EC2 allows the current from the collapse of the
injector magnetic field to flow to the positive supply rail (~14V); it
doesn't oppose this. A resistor allowing this current to flow would
also result in a close delay since the current flowing is what maintains
the magnetic field during this delay. What is needed is a way to
decrease the rate of voltage rise just after the EC2 pulse ends so
arcing in the A/B selection relay is suppressed. After the relay
contacts open enough that an arc is no longer possible (which shouldn't
take long) an open circuit condition now would allow the injector to
close quickly. The arcing may or may not be a problem any given tim Ed
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