X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao107.cox.net ([68.230.241.39] verified) by logan.com (CommuniGate Pro SMTP 5.2.14) with ESMTP id 3682933 for flyrotary@lancaironline.net; Mon, 15 Jun 2009 11:47:09 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.39; envelope-from=alventures@cox.net Received: from fed1rmimpo03.cox.net ([70.169.32.75]) by fed1rmmtao107.cox.net (InterMail vM.7.08.02.01 201-2186-121-102-20070209) with ESMTP id <20090615154634.RFYV18948.fed1rmmtao107.cox.net@fed1rmimpo03.cox.net> for ; Mon, 15 Jun 2009 11:46:34 -0400 Received: from BigAl ([72.192.135.181]) by fed1rmimpo03.cox.net with bizsmtp id 4FmZ1c00G3uzsQg04FmZTM; Mon, 15 Jun 2009 11:46:33 -0400 X-VR-Score: 0.00 X-Authority-Analysis: v=1.0 c=1 a=BBo6kb-L62sA:10 a=hiFi1wAUIMkc7ubkwrwA:9 a=VS_4Izc8Ywvwy0oaYi5ohInH1CYA:4 a=VIhxNKU8sfricemtpfwA:9 a=jf8l2hII0aaGLllOSfsA:7 a=fHR1L86Lvm30ibhCC4Ru5iGsXu0A:4 X-CM-Score: 0.00 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Over Voltage? Date: Mon, 15 Jun 2009 08:47:19 -0800 Message-ID: <3F7AF836DF7A49C0A4AB481E60E99C60@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0024_01C9ED95.E4ACCE10" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6838 In-Reply-To: Importance: Normal x-mimeole: Produced By Microsoft MimeOLE V6.00.2900.5579 thread-index: AcnttMYWt7/gUAndTgmWfMzy1wY90AAIgGYg This is a multi-part message in MIME format. ------=_NextPart_000_0024_01C9ED95.E4ACCE10 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable =20 I guess I really shoud get around to doing that. Seems to me that I remember the all the parts for a crow-bar system being about $300. Is = that not the case? I have already modified my alternator so that if I shut = off the b-field I can shut down the alternator - do I need to make further internal modifications to the alternaror to use an external regulator? =20 Dave; =20 If you have already made the internal mod to the alternator = (disconnecting the connection from the output to the voltage regulator) then all you = need to do is add the =91crowbar circuit=92 between the field circuit breaker = output to ground. The =91crowbar=92 goes to short in the event of over-voltage, = trips the breaker shutting down the alternator. I bought the crowbar circuit = from Aeroelectric Connection for about $17 (It=92s just a little potted = circuit maybe =BE=94 dia with a couple of leads). But that was then. =20 I have noted a characteristic of the regulator in the Mitsubishi = alternator is that the voltage cycles over small range as you also noted. Maybe .3 = to .5 volts or so, and at a frequency of a few seconds. What I noted prior = to replacing my regulator was the range of the cycle increased, as well as = the average voltage going up.=20 =20 Al ------=_NextPart_000_0024_01C9ED95.E4ACCE10 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

I guess I really shoud get around to doing = that. Seems to me that I remember the all the parts for a crow-bar system = being about $300. Is that not the case? I have already modified my alternator so that if I shut off the b-field I can shut down the = alternator - do I need to make further internal modifications to the alternaror to = use an external regulator?

Dave;

If you have already made the = internal mod to the alternator (disconnecting the connection from the output to = the voltage regulator) then all you need to do is add the ‘crowbar = circuit’ between the field circuit breaker output to ground. The = ‘crowbar’ goes to short in the event of over-voltage, trips the breaker shutting down = the alternator. I bought the crowbar circuit from Aeroelectric = Connection for about $17 (It’s just a little potted circuit maybe ¾” = dia with a couple of leads). But that was then.

I have noted a characteristic of = the regulator in the Mitsubishi alternator is that the voltage cycles over = small range as you also noted. Maybe .3 to .5 volts or so, and at a = frequency of a few seconds. What I noted prior to replacing my regulator was the = range of the cycle increased, as well as the average voltage going up. =

Al

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