X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao102.cox.net ([68.230.241.44] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3830434 for flyrotary@lancaironline.net; Mon, 31 Aug 2009 14:17:42 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.44; envelope-from=alventures@cox.net Received: from fed1rmimpo01.cox.net ([70.169.32.71]) by fed1rmmtao102.cox.net (InterMail vM.8.00.01.00 201-2244-105-20090324) with ESMTP id <20090831181705.JFJI12000.fed1rmmtao102.cox.net@fed1rmimpo01.cox.net> for ; Mon, 31 Aug 2009 14:17:05 -0400 Received: from BigAl ([72.192.133.78]) by fed1rmimpo01.cox.net with bizsmtp id b6H51c00B1hf1Cg036H5hf; Mon, 31 Aug 2009 14:17:05 -0400 X-VR-Score: 0.00 X-Authority-Analysis: v=1.0 c=1 a=O4KcONCDyRsA:10 a=DSQsvA4HOrJYeLcIPJkA:9 a=CqTWESV01vVOZGmL9iQA:7 a=goQW8hm2aw8-JZPEVT4Rr1X10N4A:4 a=urRYqHZHsvpaadYZ:21 a=WwmscUStjA-Qyo_F:21 a=UClSrZc0rB_X_rFp694A:9 a=gVrqVbPmQM18Tm5WE9EA:7 a=O2xZ25LkcUrzY-NL3PthpI0jxjgA:4 X-CM-Score: 0.00 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: FW: More Charging Circuit Info Date: Mon, 31 Aug 2009 11:18:09 -0800 Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0031_01CA2A2C.B8524F10" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6838 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 Thread-Index: Acop8JttWp2rYeMbRVGZIGoCdifLagAfURzA This is a multi-part message in MIME format. ------=_NextPart_000_0031_01CA2A2C.B8524F10 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable From Mike - ...ensure that the field is de-energized while cranking = the engine. =20 And I will respectfully disagree with that - at least until somebody can prove me wrong. The output current is a function of rpm as well as what = the voltage regulator is demanding. From what I can find, I conclude that alternators typically won't put out their rated current until they get spinning about 1500 - 2000 rpm, or more (which is usually about double engine rpm). So there is no risk of damaging the rectifier diodes at cranking speed. =20 I'm going to guess that it is a worse shock to the electronics if the = field is suddenly turned on at higher rpm when the regulator is on full demand = - although I don't think it's an issue. =20 Off topic, another 1.2 hours closer to completing my Phase 1. This was = the first flight that after I landed I didnt have anything on my list to fix before the next flight. 95 degrees OAT at takeoff today and the oil temp = got to 200 at the top of the climb to 5000' but backed off to 192 after I leveled. H2O temp never above 180. Starting to gain some confidence in = it.=20 Contrary to our friend George's faint praise:-), I'd say your temps are excellent. If it does that well at OAT of 95 F; then your next thing = will be to think about adjustable cowl flap to reduce cooling drag at cruise = on a cooler day. Al ------=_NextPart_000_0031_01CA2A2C.B8524F10 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

From = Mike   - …..ensure = that the field is de-energized while cranking the engine.

 

And I will respectfully disagree = with that – at least until somebody can prove me wrong.  The = output current is a function of rpm as well as what the voltage regulator is demanding.  From what I can find, I conclude that alternators = typically won’t put out their rated current until they get spinning about 1500 – = 2000 rpm, or more (which is usually about double engine rpm). So there is no risk = of damaging the rectifier diodes at cranking speed.

 

I’m going to guess that it = is a worse shock to the electronics if the field is suddenly turned on at = higher rpm when the regulator is on full demand – although I don’t = think it’s an issue.

 

=

 Off topic, another 1.2 hours closer to completing my Phase 1. This was the = first flight that after I landed I didnt have anything on my list to fix = before the next flight. 95 degrees OAT at takeoff today and the oil temp got = to 200 at the top of the climb to 5000' but backed off to 192 after I leveled. = H2O temp never above 180. Starting to gain some confidence in it. =

Contrary to our friend George’s faint praiseJ, I’d say your temps are excellent.  If it does = that well at OAT of 95 F; then your next thing will be to think about = adjustable cowl flap to reduce cooling drag at cruise on a cooler = day.

Al

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