X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from aspensprings.uwyo.edu ([129.72.10.32] verified) by logan.com (CommuniGate Pro SMTP 5.4.5) with ESMTPS id 5565896 for flyrotary@lancaironline.net; Tue, 29 May 2012 11:42:12 -0400 Received-SPF: none receiver=logan.com; client-ip=129.72.10.32; envelope-from=SBoese@uwyo.edu Received: from ponyexpress-ht3.uwyo.edu (extlb.uwyo.edu [172.26.4.4]) by aspensprings.uwyo.edu (8.14.4/8.14.4) with ESMTP id q4TFfMQq013200 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=FAIL) for ; Tue, 29 May 2012 09:41:33 -0600 (MDT) (envelope-from SBoese@uwyo.edu) Received: from ponyexpress-m10.uwyo.edu ([fe80::60dd:cb9e:6f71:3d48]) by ponyexpress-ht3.uwyo.edu ([fe80::4cde:db24:a0a9:ba5%15]) with mapi id 14.01.0339.001; Tue, 29 May 2012 09:41:31 -0600 From: "Steven W. Boese" To: Rotary motors in aircraft Subject: ! Thread-Topic: ! Thread-Index: AQHNPbFoVfOMUtzWU0Co1sBkeM3mKQ== Date: Tue, 29 May 2012 15:41:29 +0000 Message-ID: <3E8191F276108F4481AB0721BBA9269E05C4B739@ponyexpress-m10.uwyo.edu> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [75.228.174.116] Content-Type: multipart/alternative; boundary="_000_3E8191F276108F4481AB0721BBA9269E05C4B739ponyexpressm10u_" MIME-Version: 1.0 --_000_3E8191F276108F4481AB0721BBA9269E05C4B739ponyexpressm10u_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Ed, Depending on the version of EC2, inductive spikes of over 40 volts are seen= with the newer versions and over 60 volts are seen on the older ones. The= current drawn through the resistor doesn't have to pull the injector open.= It just has to delay the injector from closing. When this happens, the i= njector would appear to be working, but would deliver more fuel than the ot= hers. Remember the Alamo! ... oops... Snubber, that is. Steve Boese RV6A, 1986 13B NA, RD1A, EC2 ________________________________ From: Rotary motors in aircraft [flyrotary@lancaironline.net] on behalf of = Ed Anderson [eanderson@carolina.rr.com] Sent: Tuesday, May 29, 2012 9:18 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: injector imbalance Mark, it does not take much resistance to protect the injector from current= draws by other devices. I install a 200 ohm resistor between my EFISM and= the driving injector. That way at a nominal 12 volts - the most current t= he other device would draw (if shorted to ground) is I =3D E/R =3D 12/200 = =3D 60 ma (probably much less is the device is probably not a direct ground= ) not enough to pull your injector open. I put it in there (as close to the injector as I could) so that if by chan= ce my EFISM lead from the injector got shorted to ground it would not pull = the injector open. The resistance is not critical, I have used from 100-500 ohms. You could i= ncrease the resistance until your other device stopped working (and then re= duce the resistance a bit from there). The quickest was to see if that is the problem is simply to disconnect that= aux lead to injector. Ed From: Mark Steitle Sent: Tuesday, May 29, 2012 11:02 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: injector imbalance Steve, I almost understand what you're telling me. Bill Shultz commented on the B= lue Mountain EFIS using the #1 injector for RPM. So, if the BMA EFIS is co= nnected to the #1 injector lead, then it could be causing the over rich con= dition on that rotor. I'm not sure if I did that or not as my BMA RPM ind= icator has never worked. It has been many years since I installed the EFIS= , so I don't recall if this was done or not. But this will be the next thi= ng I will check. Thanks, Mark On Tue, May 29, 2012 at 9:47 AM, Steven W. Boese > wrote: Mark, If a device is connected to the EC2 side of the primary injector of rotor 1= and this device has diode protection from the inductive spike produced by = the injector winding, then this injector will deliver more fuel than the in= jector pulse width would indicate. The appearance on the O-scope would mor= e evident in the lack of an inductive spike for this injector rather than i= n a difference in the signal pulse width. Steve Boese RV6A, 1986 13B NA, RD1A, EC2 No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2178 / Virus Database: 2425/5030 - Release Date: 05/29/12 --_000_3E8191F276108F4481AB0721BBA9269E05C4B739ponyexpressm10u_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Ed,

 

Depending on the version of EC2, inductive spikes of over 40 volts are s= een with the newer versions and over 60 volts are seen on the older ones.&n= bsp; The current drawn through the resistor doesn't have to pull the inject= or open.  It just has to delay the injector from closing.  When this happens, the injector would appear to be wor= king, but would deliver more fuel than the others.  Remember the Alamo= !  ... oops... Snubber, that is.

 

Steve Boese
RV6A, 1986 13B NA, RD1A, EC2

 

 

From: Rotary motors in aircraft [flyrotary= @lancaironline.net] on behalf of Ed Anderson [eanderson@carolina.rr.com] Sent: Tuesday, May 29, 2012 9:18 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: injector imbalance

Mark, it does not take much resistance to protect= the injector from current draws by other devices.  I install a 200 oh= m resistor between my EFISM and the driving injector.  That way at a n= ominal 12 volts - the most current the other device would  draw (if shorted to ground) is I =3D E/R =3D 12/200 =3D= 60 ma (probably much less is the device is probably not a direct ground)&n= bsp;not enough to pull your injector open. 
 
 I put it in there (as close to the injector= as I could) so that if by chance my EFISM lead from the injector got short= ed to ground it would not pull the injector open.
 
The resistance is not critical, I have used from = 100-500 ohms.  You could increase the resistance until your other devi= ce stopped working (and then reduce the resistance a bit from there).
 
The quickest was to see if that is the problem is= simply to disconnect that aux lead to injector.
 
Ed

Sent: Tuesday, May 29, 2012 11:02 AM
Subject: [FlyRotary] Re: injector imbalance

Steve,

I almost understand what you're telling me.  Bill Shultz commente= d on the Blue Mountain EFIS using the #1 injector for RPM.  So, if the= BMA EFIS is connected to the #1 injector lead, then it could be causing th= e over rich condition on that rotor.   I'm not sure if I did that or not as my BMA RPM indicator has never worked. &n= bsp;It has been many years since I installed the EFIS, so I don't recall if= this was done or not.  But this will be the next thing I will check. =  

Thanks,

No virus found in this message.
Checked by AVG - www.avg.c= om
Version: 2012.0.2178 / Virus Database: 2425/5030 - Release Date: 05/29/12

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