X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.121] verified) by logan.com (CommuniGate Pro SMTP 5.1.12) with ESMTP id 2391538 for flyrotary@lancaironline.net; Wed, 17 Oct 2007 09:24:24 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.121; envelope-from=eanderson@carolina.rr.com Received: from edward2 ([24.74.103.61]) by cdptpa-omta01.mail.rr.com with SMTP id <20071017132346.CNDG6760.cdptpa-omta01.mail.rr.com@edward2> for ; Wed, 17 Oct 2007 13:23:46 +0000 Message-ID: <001401c810c1$0ae3e860$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: EC2 20B Injector Power Circuits Date: Wed, 17 Oct 2007 09:24:27 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0011_01C8109F.83A285D0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3138 This is a multi-part message in MIME format. ------=_NextPart_000_0011_01C8109F.83A285D0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Hi Bob, I strongly suggest you mount your EC2 where it is easy to get at. I = mounted my "out of the way" forward and up under my instrument panel = thinking there would never be any need to remove it {:>).=20 I have found that laying on my back with a spar under my spine ,my = shoulders bound by the fuselage side and my stick is getting harder as I = mature {:>). Tracy continues to upgrade and enhance the EC2 (and = probably will with the 20B version) so, you will likely removed it for = upgrades if nothing else. So far I have removed my (for various = reasons) probably half a dozen times. Ed ----- Original Message -----=20 From: bmears9413@aol.com=20 To: Rotary motors in aircraft=20 Sent: Wednesday, October 17, 2007 9:09 AM Subject: [FlyRotary] Re: EC2 20B Injector Power Circuits So does this mean I shouldnt finish installing my EC2 cause I may have = to send it back to Tracy? Nows the time for me. I'm installing now. Bob Mears Supermarine Spitfire -----Original Message----- From: Joe Ewen To: Rotary motors in aircraft Sent: Sun, 14 Oct 2007 10:28 pm Subject: [FlyRotary] Re: EC2 20B Injector Power Circuits Hi Bob, Don't know if you don't ask. A diode is a device that allows current = to flow only in one direction (DC circuit.) Schottky is a particular = diode construction. One desirable feature of a Schottky is that it has = a low forward voltage drop. All diodes have a drop in voltage (like a = small resistor.) In this case, the lower voltage drop allows the = injectors to continue firing slightly longer than other diode types in = the event of an alternator failure and lowering battery voltage. On the 20B, the injector control lines are wired together, installing = the diodes prevents the current / voltage from back feeding between the = primary and secondary circuits and the possible failure modes I noted = earlier. Application of diode(s) in this manner is typically referred = to as isolation diodes. Since the EC2 controller internal jumps the 2 controller power feeds, = I installed isolation diodes (Schottky) to prevent similar problems = between the 2 supply circuits. You may also find diodes useful in making annunciator press to test = circuits. If you have 2 devices such as a transponder and a GPS that = both need to share altitude encoder inputs, isolation diodes would be = used. Of course with any avionics installations, follow the = manufactures guidelines. Joe ----- Original Message -----=20 From: bob.kaufmann=20 To: Rotary motors in aircraft=20 Sent: Sunday, October 14, 2007 10:16 PM Subject: [FlyRotary] Re: EC2 20B Injector Power Circuits Al=20 Hate to continue to display my ignorance but what is a Schottky = diodes. When it comes to electronics I=E2=80=99m as dumb as a stump. Bob K From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of Al Gietzen Sent: Sunday, October 14, 2007 5:42 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: EC2 20B Injector Power Circuits Joe; You are right. We discovered this crossfeed issue some time back. = Is applies only to the 20B version as the 13B has separate drivers for = each set. Install Schottky diodes in the circuits for each injector. = Tracy is aware of this, and has installed the diodes in his as well. Al -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of Joe Ewen Sent: Sunday, October 14, 2007 3:20 PM To: Rotary motors in aircraft Subject: [FlyRotary] EC2 20B Injector Power Circuits I have been testing my wiring harness from the EC2. I found a = behavior that I did not expect. The manual drawing (EC2 manual) show a = single injector supply that splits at the Injector primary and secondary = disable switches. On my installation, I have 2 separate feeder = circuits, supply Primary comes from battery 1, and supply Secondary = comes from battery 2. I did this for redundancy. If I had a failure = such as a short to ground in either circuit, its related overload should = trip, but the other circuit should remain active. =20 While testing the injector circuits, I noticed what I would term an = abnormality. With both injector disable switches in the enable = position, I turned on the power for the primary circuit (I have LED = indicators on all circuits that annunciate power present) and the = secondary circuit also showed power present even though the power switch = for the secondary circuit was off. The same is true when the secondary = circuit is engaged and the primary is off. =20 Initially this led me to think I had miss wired something in the = circuit. After checking out the wiring, I found no issues. So I took a = closer look at the wiring diagram in the manual. It turns out the power = was being back feed through the injectors to the opposite circuit. On = the 20B version of the EC2, the injector control lines for each rotors = injectors are junctioned going into the EC2. For example the Rotor 1 = Primary and Secondary control lines are junctioned into a single input = point at the EC2. =20 I can see several situations where this may lead to undesirable = operation. For example, if the Primary circuit had a hard short to = ground, it would take out the primary circuit's overload (CB or Fuse.) = Since the primary and secondary circuits are electrically connected on = the control line, the other circuit would also trip. Another situation = that could occur is a medium to high resistance short. Current would = then flow uncontrolled through the unaffected circuit's injector to the = affected circuit's injector then to the resistance short. This could = keep both injectors on 100%. While this situation is unlikely, it seems = possible. I believe the 13B version uses separate control lines for each = injector, so this in not likely to be an issue on the 13B version. It appears that isolation diodes are needed to prevent these = possible problems. Before making any changes I have to look the circuit = over more closely, as well as a call to Tracy on the next service day. = My question to the group, especially anyone with a 20B, is am I looking = at this wrong? Thanks, Joe -------------------------------------------------------------------------= ----- Email and AIM finally together. You've gotta check out free AOL Mail! ------=_NextPart_000_0011_01C8109F.83A285D0 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable =EF=BB=BF
Hi Bob,
 
I strongly suggest you mount your EC2 where it = is easy to=20 get at.  I mounted my "out of the way" forward and up under my = instrument=20 panel thinking there would never be any need to remove it=20 {:>). 
 
 I have found that laying on my back with a = spar=20 under my spine ,my shoulders bound by the fuselage side and my stick is = getting=20 harder as I mature {:>).   Tracy continues to upgrade and = enhance=20 the EC2 (and probably will with the 20B version) so, you will likely = removed it=20 for upgrades if nothing else.  So far I have removed my (for = various=20 reasons) probably half a dozen times.
 
Ed
----- Original Message -----
From:=20 bmears9413@aol.com
Sent: Wednesday, October 17, = 2007 9:09=20 AM
Subject: [FlyRotary] Re: EC2 = 20B Injector=20 Power Circuits

So does this mean I shouldnt finish installing my EC2 = cause I=20 may have to send it back to Tracy? Nows the time for me. I'm = installing=20 now.

Bob Mears
Supermarine Spitfire


-----Original = Message-----
From: Joe Ewen <Jewen@comporium.net>
To: = Rotary=20 motors in aircraft <flyrotary@lancaironline.net>
Sent:=20 Sun, 14 Oct 2007 10:28 pm
Subject: [FlyRotary] Re: EC2 20B Injector = Power=20 Circuits

Hi Bob,
Don't know if you don't ask.  A = diode is a=20 device that allows current to flow only in one direction (DC = circuit.) =20 Schottky is a particular diode construction.  One desirable = feature of a=20 Schottky is that it has a low forward voltage drop.  All diodes = have a=20 drop in voltage (like a small resistor.)  In this case, the lower = voltage=20 drop allows the injectors to continue firing slightly longer than = other diode=20 types in the event of an alternator failure and lowering battery=20 voltage.
 
On the 20B, the injector control = lines are wired=20 together, installing the diodes prevents the current / voltage from = back=20 feeding between the primary and secondary circuits and the possible = failure=20 modes I noted earlier.  Application of diode(s) in this manner is = typically referred to as isolation diodes.
 
Since the EC2 controller internal = jumps the 2=20 controller power feeds, I installed isolation diodes (Schottky) to = prevent=20 similar problems between the 2 supply circuits.
 
You may also find diodes useful in=20 making annunciator press to test circuits.  If you have 2=20 devices such as a transponder and a GPS that both need to share = altitude=20 encoder inputs, isolation diodes would be used.  Of course with = any=20 avionics installations, follow the manufactures = guidelines.
 
Joe
----- Original Message -----
From:=20 bob.kaufmann
To: Rotary motors in = aircraft=20
Sent: Sunday, October 14, = 2007 10:16=20 PM
Subject: [FlyRotary] Re: EC2 = 20B=20 Injector Power Circuits

Al=20
 
Hate=20 to continue to display my ignorance but what is a Schottky = diodes. =20 When it comes to electronics I=E2=80=99m as dumb as a = stump.
 
Bob=20 K
 
From: = Rotary motors=20 in aircraft [mailto:flyrotary@lancaironli= ne.net]=20 On Behalf Of Al Gietzen
Sent: Sunday, October 14, = 2007 5:42=20 PM
To: Rotary motors in aircraft
Subject: = [FlyRotary]=20 Re: EC2 20B Injector Power Circuits
 
Joe;
 
You=20 are right.  We discovered this crossfeed issue some time back. =  Is=20 applies only to the 20B version as the 13B has separate drivers for = each=20 set.  Install Schottky diodes in the circuits for each = injector. =20 Tracy is aware of this, and has installed the diodes in his as=20 well.
 
Al
 
-----Original=20 Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironli= ne.net]=20 On Behalf Of Joe Ewen
Sent: Sunday, October 14, = 2007 3:20=20 PM
To: Rotary motors in aircraft
Subject: = [FlyRotary]=20 EC2 20B Injector Power Circuits
 
I have = been=20 testing my wiring harness from the EC2.  I found a behavior = that I did=20 not expect.  The manual drawing (EC2 manual) show a single = injector=20 supply that splits at the Injector primary and secondary disable=20 switches.  On my installation, I have 2 separate feeder = circuits,=20 supply Primary comes from battery 1, and supply Secondary comes = from=20 battery 2.  I did this for redundancy.  If I had a failure = such as=20 a short to ground in either circuit, its related overload should = trip, but=20 the other circuit should remain active. 
 
While = testing the=20 injector circuits, I noticed what I would term an abnormality.  = With=20 both injector disable switches in the enable position, I turned on = the power=20 for the primary circuit (I have LED indicators on all circuits that=20 annunciate power present) and the secondary circuit also showed = power=20 present even though the power switch for the secondary circuit was=20 off.  The same is true when the secondary circuit is engaged = and the=20 primary is off. 
 
Initially this=20 led me to think I had miss wired something in the circuit.  = After=20 checking out the wiring, I found no issues.  So I took a closer = look at=20 the wiring diagram in the manual.  It turns out the power was = being=20 back feed through the injectors to the opposite circuit.  On = the 20B=20 version of the EC2, the injector control lines for each rotors = injectors are=20 junctioned going into the EC2.  For example the Rotor 1 Primary = and=20 Secondary control lines are junctioned into a single input point at = the=20 EC2. 
 
I can = see several=20 situations where this may lead to undesirable operation.  For = example,=20 if the Primary circuit had a hard short to ground, it would take out = the=20 primary circuit's overload (CB or Fuse.)  Since the primary and = secondary circuits are electrically connected on the control line, = the other=20 circuit would also trip.  Another situation that could occur is = a=20 medium to high resistance short.  Current would then flow = uncontrolled=20 through the unaffected circuit's injector to the affected circuit's = injector=20 then to the resistance short.  This could keep both injectors = on=20 100%.  While this situation is unlikely, it seems=20 possible.
 
I=20 believe the 13B version uses separate control lines for each = injector,=20 so this in not likely to be an issue on the 13B = version.
 
It = appears that=20 isolation diodes are needed to prevent these possible = problems.  Before=20 making any changes I have to look the circuit over more closely, as = well as=20 a call to Tracy on the next service day.  My question to the = group,=20 especially anyone with a 20B, is am I looking at this=20 wrong?
 
Thanks,
Joe
Email and AIM finally together. You've gotta check out free AOL Mail!
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