X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [24.25.9.103] (HELO ms-smtp-04-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.3c5) with ESMTP id 930854 for flyrotary@lancaironline.net; Tue, 03 May 2005 07:08:48 -0400 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.103; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-189-178.carolina.res.rr.com [24.74.189.178]) by ms-smtp-04-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id j43B7xL5006260 for ; Tue, 3 May 2005 07:08:00 -0400 (EDT) Message-ID: <001301c54fd0$602ab290$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] ECU power - was fuses vs breakers Date: Tue, 3 May 2005 07:08:03 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0010_01C54FAE.D8E49510" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0010_01C54FAE.D8E49510 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MessageThe answer is yes, the engine will continue to run. In fact, = talking with Tracy he assumed that most folks would kill the engine by = turning off the master switch - which would indeed remove power from the = EC2. If I had not installed injector switches, I would indeed have to = kill the master switch to stop the engine. So I can verify it will run = with the power switch to the EC2 OFF provided power to the injectors are = on. However, since I don't know what components the sneak circuit = involves or how much load they may be capable of, to be on the safe = side, I normally do not run it with just the injector power. Ed ----- Original Message -----=20 From: Al Gietzen=20 To: Rotary motors in aircraft=20 Sent: Tuesday, May 03, 2005 12:24 AM Subject: [FlyRotary] ECU power - was fuses vs breakers By the way, Tracy's ECU can be powered through two different ways. = The original intended way and a sneak circuit way through the powering = of the injectors. I found this out when I wired a switch to the EC2 = CPU power terminal. When I turned off the switch the EC2 did not turn = off because the injectors still had voltage and there was a sneak = circuit that kept the EC2 with DC power. Tracy may have eliminated = that sneak circuit in later versions - but its there on mine. Yes; I had noted that on mine as well - at least that the light would = stay on if the injectors were on. I don't think I verified whether the = engine would continue running with the ECU off. Al=20 ----- Original Message -----=20 From: Al Gietzen=20 To: Rotary motors in aircraft=20 Sent: Monday, May 02, 2005 2:28 PM Subject: [FlyRotary] fuses vs circuit breakers - or something else I think the key point in this discussion is not so much fuses vs = circuit breakers; but that we follow the philosophy of not having single = point failures in the flight critical systems. The rotary engine has = dual plugs/rotor, most induction systems have two injectors/rotor; = Tracy's ECU has dual units built in (although unfortunately, common = input power point); and most of us are using dual fuel pumps. Separate = and independent feeds to each of these can eliminate single point = failures.=20 The choice of fuse or breaker is as much opinion as it is technical = fact, and a winning argument for either in our airplanes isn't going to = happen. There are advantages and disadvantages to both. I have separate and independent power feeds to each set of coils, to = each set of injectors, to each pump, and to the ECU. I have a mix of = breakers and fuses. I happened to choose fuses (blade type) for the = injectors, coils, and pumps somewhat along the lines of Jim's argument - = I can protect those wires with 15 amp fuses. The ECU has one circuit = through a breaker, and one fused. These circuits are as simple and = direct as possible. Battery - to fuse - to disable switch - to = component. No intermediate contactors or connectors to fail. Of course = I also have two batteries. Fuses, of course, cost nothing, and can be changed out on a whim; so = there is no reason for them ever to be old and fatigued. CB's are a = thermal switch; a bit more complex, expensive and generally difficult to = change, so they are likely to get old. That will be the only point I = will make either way. You choose; CB or fuse. I think that choice is less important than = how you design and execute your circuit. FWIW, Al -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of Russell Duffy Sent: Monday, May 02, 2005 8:21 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: finally changed to fuses vs circuit = breakers=20 You've been working field service long enough to know that fuses go bad, too. They de-solder; they break due to vibration; the ends corrode and lose connectivity. I've seen this happen on cheesy fuse holders. I have never seen, or = heard of it happening on an automotive fuse. Now, don't start telling = me stories of some crappy old car that had rats in the fuse holder, = because that ain't comparable. =20 I have items like fuel pumps separately fused, and to the wiring = rating, so they should never blow unless there's a good reason. Items = like the EC-2 are directly tied to power, via two attachment points. = This is how Tracy recommends it, because the controller will be it's own = fuse. =20 If I had the panel space, and believed CB's offered any significant = benefit, I wouldn't care about the cost and weight. =20 Gotta go pick up my new company van, and replace a switch in Mobile. Rusty (discussion for entertainment only) ------=_NextPart_000_0010_01C54FAE.D8E49510 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
The answer is yes, the engine will = continue to=20 run.  In fact, talking with Tracy he assumed that most folks would = kill the=20 engine by turning off the master switch - which would indeed remove = power from=20 the EC2.  If I had not installed injector switches, I would indeed = have to=20 kill the master switch to stop the engine.  So I can verify it will = run=20 with the power switch to the EC2 OFF provided power to the injectors are = on.  However, since I don't know what components the sneak circuit = involves=20 or how much load they may be capable of, to be on the safe side,  I = normally do not run it with just the injector power.
 
Ed
----- Original Message -----
From:=20 Al = Gietzen=20
Sent: Tuesday, May 03, 2005 = 12:24=20 AM
Subject: [FlyRotary] ECU power = - was=20 fuses vs breakers

  By the way,=20 Tracy's ECU can=20 be powered through two different ways.  The original intended way = and a=20 sneak circuit way through the powering of the injectors.  I found = this=20 out when I wired a  switch to the EC2 CPU power terminal.  = When I=20 turned off the switch the EC2 did not turn off because the injectors = still had=20 voltage and there was a sneak circuit that kept the EC2 with DC = power. =20 Tracy may=20  have eliminated that sneak circuit in later versions - but its = there on=20 mine.

 

Yes; I = had noted=20 that on mine as well =96 at least that the light would stay on if the = injectors=20 were on.  I don=92t think I verified whether the engine would = continue=20 running with the ECU off.

 

Al=20

 

----- Original Message = -----=20

From: Al = Gietzen=20

To: Rotary motors in = aircraft=20

Sent:=20 Monday, May 02,=20 2005 2:28=20 PM

Subject:=20 [FlyRotary] fuses vs circuit breakers - or something=20 else

 

 

I=20 think the key point in this discussion is not so much fuses vs = circuit=20 breakers; but that we follow the philosophy of not having single = point=20 failures in the flight critical systems.  The rotary engine has = dual=20 plugs/rotor, most induction systems have two injectors/rotor;=20 Tracy=92s = ECU has dual=20 units built in (although unfortunately, common input power point); = and most=20 of us are using dual fuel pumps.  Separate and independent = feeds to=20 each of these can eliminate single point failures. =

 

The=20 choice of fuse or breaker is as much opinion as it is technical = fact, and a=20 winning argument for either in our airplanes isn=92t going to = happen.=20  There are advantages and disadvantages to = both.

 

I=20 have separate and independent power feeds to each set of coils, to = each set=20 of injectors, to each pump, and to the ECU.  I have a mix of = breakers=20 and fuses. I happened to choose fuses (blade type) for the = injectors, coils,=20 and pumps somewhat along the lines of Jim=92s argument =96 I can = protect those=20 wires with 15 amp fuses.  The ECU has one circuit through a = breaker,=20 and one fused.  These circuits are as simple and direct as = possible.=20 Battery - to = fuse - to=20 disable switch =96 to component.  No intermediate contactors or = connectors to fail.  Of course I also have two=20 batteries.

 

Fuses, = of course,=20 cost nothing, and can be changed out on a whim; so there is no = reason for=20 them ever to be old and fatigued. CB=92s are a thermal switch; a bit = more=20 complex, expensive and generally difficult to change, so they are = likely to=20 get old.  That will be the only point I will make either=20 way.

 

You=20 choose; CB or fuse.  I think that choice is less important than = how you=20 design and execute your circuit.

 

FWIW,

 

Al

 

 

 

 

-----Original=20 Message-----
From: Rotary=20 motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Russell = Duffy
Sent: Monday, May 02,=20 2005 8:21=20 AM
To: Rotary motors in=20 aircraft
Subject: = [FlyRotary] Re: finally changed to fuses vs circuit breakers=20

 

You've been working field service long = enough to=20 know
that fuses go bad, too.  They de-solder; they break due = to
vibration; the ends corrode and lose = connectivity.

I've=20 seen this happen on cheesy fuse holders.  I have never = seen, or=20 heard of it happening on an automotive fuse.  Now, = don't start=20 telling me stories of some crappy old car that had rats in the fuse = holder,=20 because that ain't comparable.  

 

I have=20 items like fuel pumps separately fused, and to the wiring rating, so = they=20 should never blow unless there's a good reason.  Items like the = EC-2=20 are directly tied to power, via two attachment points.  = This is=20 how Tracy = recommends it,=20 because the controller will be it's own=20 fuse.  

 

If I=20 had the panel space, and believed CB's offered any significant = benefit, I=20 wouldn't care about the cost and = weight.  

 

Gotta=20 go pick up my new company van, and replace a switch in=20 Mobile.

 

Rusty=20 (discussion for entertainment only)

 

 

 

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