Return-Path: <13brv3@bellsouth.net> Received: from imf18aec.mail.bellsouth.net ([205.152.59.66] verified) by logan.com (CommuniGate Pro SMTP 4.1.5) with ESMTP id 2620158 for flyrotary@lancaironline.net; Wed, 01 Oct 2003 13:37:43 -0400 Received: from rad ([68.212.15.208]) by imf18aec.mail.bellsouth.net (InterMail vM.5.01.05.27 201-253-122-126-127-20021220) with ESMTP id <20031001173740.LWML1874.imf18aec.mail.bellsouth.net@rad> for ; Wed, 1 Oct 2003 13:37:40 -0400 From: "Russell Duffy" <13brv3@bellsouth.net> To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: alternator choice? Date: Wed, 1 Oct 2003 12:37:39 -0500 Message-ID: <005501c38842$b637b8b0$0201a8c0@rad> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0056_01C38818.CD61B0B0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.4510 Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 In-Reply-To: This is a multi-part message in MIME format. ------=_NextPart_000_0056_01C38818.CD61B0B0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable What was the reason for going external regulator? By going to a dual alternator can't I just switch one off if it goes bonkers (or have an overvoltage relay do that for me)? =20 Hi Marko, =20 =20 The reason for external regulators is the ability to remove the field current, and turn off the alternator if needed. Most internal = regulators require an external current to initially excite the alternator, but once it's going, you can't turn it off. Removing the external voltage does = more harm than good, because it can raise the output of the alternator by removing it's reference voltage. You could also use a contactor to disconnect the B lead, but the alternator will keep on pumping, and = possibly burn up if it really has a serious problem. =20 =20 That being said, modern alternators and internal regulators are sooooo = very reliable, that it's almost paranoid to think they will fail in a way = that will damage anything in your electrical system. I did like the fact = that the UltraMini said it came in a version that could be turned off when desired. I'd need to ask more questions about that. =20 =20 Cheers, Rusty =20 PS- thanks for the Ebay link, but I just picked up a non-cracked stock manifold last night for $52. =20 ------=_NextPart_000_0056_01C38818.CD61B0B0 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable Message

What was the reason for going external regulator? By = going to a=20 dual alternator can't I just switch one off if it goes bonkers (or have = an=20 overvoltage relay do that for me)?

 
Hi = Marko, =20
 
The = reason for external=20 regulators is the ability to remove the field current, and turn off the=20 alternator if needed.  Most internal regulators require an external = current=20 to initially excite the alternator, but once it's going, you can't turn = it=20 off.   Removing the external voltage does more harm than good, = because=20 it can raise the output of the alternator by removing it's reference=20 voltage.  You could also use a contactor to disconnect the B lead, = but the=20 alternator will keep on pumping, and possibly burn up if it really has a = serious=20 problem.  
 
That = being said, modern=20 alternators and internal regulators are sooooo very reliable, that it's = almost=20 paranoid to think they will fail in a way that will damage anything in = your=20 electrical system.  I did like the fact that the UltraMini said it = came in=20 a version that could be turned off when desired.  I'd need to ask = more=20 questions about that. 
 
Cheers,
Rusty
 
PS- = thanks for the Ebay=20 link, but I just picked up a non-cracked stock manifold last night=20 for $52. 




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