X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao10.cox.net ([68.230.241.29] verified) by logan.com (CommuniGate Pro SMTP 4.3c5) with ESMTP id 943798 for flyrotary@lancaironline.net; Sat, 14 May 2005 11:30:41 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.29; envelope-from=ALVentures@cox.net Received: from BigAl ([68.7.14.39]) by fed1rmmtao10.cox.net (InterMail vM.6.01.04.00 201-2131-118-20041027) with ESMTP id <20050514152944.SFQI20235.fed1rmmtao10.cox.net@BigAl> for ; Sat, 14 May 2005 11:29:44 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Hot Alternator??? Date: Sat, 14 May 2005 08:29:50 -0700 Message-ID: <000001c55899$c4c45950$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C5585F.18658150" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C5585F.18658150 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable For those of you in the know, is it normal for an alternator to seep = current and get warm when the field coil is powered up? Is this something I = need to fix? If so, should I cancel my trip? I think it has probably been = going on for a long time but... The field current is controlled by the regulator, which is usually = internal. The regulator will only allow field current if the armature is spinning = and bat. below about 14 volts. A small amount of current is allowed at start = up via the little red light to give initial voltage. In short get the regulator checked. =20 Ian Beadle. =20 Ian; =20 With the alternator not running, the battery voltage will always be = below 14 volts; even with the charger on, so the field current will flow. Dave = has modified the internal connection the same way I did to provide external = feed to the field windings. This does not run through the warning light. So with battery voltage to the field, alternator not running; I estimate it will draw 2-3 amps. Plenty to make the alternator pretty warm after = awhile. =20 Also, I don't think tripping a 5 amp breaker in field circuit indicates anything wrong. With the battery a bit low and a, say, 60A alternator spinning, the field could draw 5 amps. I use a 7.5A breaker on my field current circuit. =20 Al =20 =20 ------=_NextPart_000_0001_01C5585F.18658150 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message
=

For those of you in the know, is it normal = for an alternator to seep current and get warm when the field coil is powered up?  Is this something I need to fix?  If so, should I cancel = my trip?  I think it has probably been going on for a long time = but...


The field current is = controlled by the regulator, which is usually internal. The regulator will only allow = field current if the armature is spinning and bat. below about 14 volts. A = small amount of current is allowed at start up via the little red light to = give initial voltage.

In short get the regulator = checked.

 

Ian = Beadle.

 

Ian;

 

With the alternator not running, = the battery voltage will always be below 14 volts; even with the charger on, = so the field current will flow.  Dave has modified the internal connection = the same way I did to provide external feed to the field windings.  = This does not run through the warning light.  So with battery voltage to the = field, alternator not running; I estimate it will draw 2-3 amps.  Plenty = to make the alternator pretty warm after awhile.

 

Also, I don’t think = tripping a 5 amp breaker in field circuit indicates anything wrong.  With the = battery a bit low and a, say, 60A alternator spinning, the field could draw 5 = amps.  I use a 7.5A breaker on my field current circuit.

 

Al

 

 

------=_NextPart_000_0001_01C5585F.18658150--