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----- Original Message -----
From: "John Slade" <sladerj@bellsouth.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Saturday, February 28, 2004 5:35 PM
Subject: [FlyRotary] EC2 power via Injectors
> >there is an unintended "sneak" circuit in the EC2 that permits power to
> the EC2 through the injectors
> I wonder if this might help explain something very strange that I noticed
> today.
> I have my EC2 fused with those fuses which contain an LED. The LED is
> supposed to light up when the fuse blows. My engine is running now. I'll
> address that in a seperate post. As I rev the engine the LED in the EC2
fuse
> glows brighter with increased RPM and goes dim again if I reduce power.
The
> fuse doesn't blow. The alternator no charge light is still on and I don't
> see any indication of charge on my voltmeter. Something is going on here,
> but I have no clue what it could be.
> John Slade
> Cozy IV (making noise on demand)
>
John here is a shot in the dark about what you might be observing. The LED
is apparently wired around the fuse. When the fuse is solid there is no
(actually there is a very, very small drop) voltage drop across the fuse.
Therefore, this no voltage difference between one end of the fuse and the
other. Since the LED must have a voltage differential to work, it says dim
(or should). However, if the fuse blows then there is the full voltage
(12-14 volts) developed across the blown fuse and LED - Voila the LED lights
up. That is the way it should work.
You don't say what type or amp rating the fuse is, but, in any case, I
suspect that during normal operation your are drawing sufficient current
through the small resistance of that fuse that it causes a small voltage
drop across the fuse. This small voltage drop causes the LED to dimly
light. Now, when you reve up the engine, the injectors are operating faster
and the average current drawn is therefore going to be higher than at idle.
More current through the fuse results in more voltage drop across the fuse
and therefore causes the LED to glow brighter.
There may be other causes, but that is my best shot.
Ed
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
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