X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imf24aec.mail.bellsouth.net ([205.152.59.72] verified) by logan.com (CommuniGate Pro SMTP 5.0c2) with ESMTP id 715731 for flyrotary@lancaironline.net; Thu, 08 Sep 2005 15:48:48 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.152.59.72; envelope-from=atlasyts@bellsouth.net Received: from ibm70aec.bellsouth.net ([68.213.226.209]) by imf24aec.mail.bellsouth.net with ESMTP id <20050908194804.GFJY7017.imf24aec.mail.bellsouth.net@ibm70aec.bellsouth.net> for ; Thu, 8 Sep 2005 15:48:04 -0400 Received: from [192.168.0.100] (really [68.213.226.209]) by ibm70aec.bellsouth.net with ESMTP id <20050908194757.UVEP20379.ibm70aec.bellsouth.net@[192.168.0.100]> for ; Thu, 8 Sep 2005 15:47:57 -0400 Mime-Version: 1.0 (Apple Message framework v728) In-Reply-To: References: Content-Type: multipart/alternative; boundary=Apple-Mail-2--274703816 Message-Id: <5DA1A3C7-D058-46BF-99E4-7097F61BE91E@bellsouth.net> From: Bulent Aliev Subject: Re: [FlyRotary] Re: Overvoltage control (help Ed A) Date: Thu, 8 Sep 2005 15:47:47 -0400 To: "Rotary motors in aircraft" X-Mailer: Apple Mail (2.728) --Apple-Mail-2--274703816 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Mark, I'm bringing my alternator to Soggy Bend for you to alter it. I don't have the Things to do it myself:) What else do I need? It will be a good learning experience for the rest. Buly On Sep 8, 2005, at 3:39 PM, Mark R Steitle wrote: > Ed, > > I wrote up step-by-step instructions a while back on converting an > ND alternator from internal regulator to external. If anyone is > interested, let me know and I will send it to them directly. This > conversion makes it so that you can shut the thing down by cutting > the power to the field wire as is the method used by the Perihelion > Design OVM. > > > > Mark S. > > > > From: Rotary motors in aircraft > [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson > Sent: Thursday, September 08, 2005 2:24 PM > To: Rotary motors in aircraft > Subject: [FlyRotary] Re: Overvoltage control (help Ed A) > > > > On alternators with internal regulators (most Auto alternators), > breaking the low current Field circuit may not (will likely not) > stop the alternator from producing current. Most of the > alternators need the field coil current to "bootleg" their start in > producing voltage, but once generating - do not need the external > field coil current to continue. That is why if you have an > alternator with an internal regulator, you can not depend on > opening the low current field coil circuit to kill the power and > why you would need a method similar to the one described in this > thread of breaking the high current (Power lead usually referred to > as the "B" lead) through a high capacity relay (Contactor) or a > "fuse". > > > > There are always side effects when interrupting a high current flow > (less if the current flow is minimal). If there is a large > inductive load (such as a large DC motor) then the back EFM can > produce a high voltage spike. There are reports that alternators > may increase their voltage dramatically if there is a sudden loss > of load -but, its never been clear to me if that is a > malfunctioning generator or caused by the lost of load - never been > tempted to experiment. However, I once had two batteries which > connected to the alternator through their contactors. I could > switch the batteries on and off the alternator line without any ill > effects - not quite the same as dumping a large load - but, after > starting on just one battery, the load was fairly high when put > back on line. However, one battery was always on-line. > > > > So not certain what effect breaking the "B" lead would be (since it > would depend on conditions) but since many designs have a "fuse" > in the "B" lead for that purpose, I am going to hazard my opinion > that the effects of breaking the "B" lead may be less serious than > what-ever bad situation is causing you to want to do that in the > first place. Ideally, of course, is to have an externally > regulator alternator (or a modified auto alternator with the > internal regulator disabled so unable to provide the field coil > internally) and a low current circuit breaker tripping mechanism > for the field coil. > > > > > > Ed > > ----- Original Message ----- > > From: WALTER B KERR > > To: Rotary motors in aircraft > > Sent: Thursday, September 08, 2005 2:14 PM > > Subject: [FlyRotary] Re: Overvoltage control (help Ed A) > > > > If you don't have a low current way to break the field current, > and need to break the high current line, then you have to used this > OV module to trip a breaker that's holding in a main contactor for > your high current "B" lead. If any of that was confusing, Ed can > explain it :-) > > > > Cheers, > > Rusty > > > > ====================================== > > Help Ed. I almost understand Rusty's comments, but Mark S left me > in the dust. Us old dogs are sometimes hard to train! > > I think that with an internal regulator; just because you break the > field current supply , a failed regulator may keep powering the > field with the internal alternator voltage. The continous breaker > in the big alternator line can protect the battery and airplane > except what happens to the alternator in the meantime if the > interal regulator is applying a large field current to the field > will the alternator burn up quiet rapidly and possible start a fire? > > > > Bernie, soggy Treasure Coast although we had a bonanza just taxi in > so must be drying out a little > > > > --Apple-Mail-2--274703816 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=ISO-8859-1 Mark, I'm bringing my alternator = to Soggy Bend for you to alter it. I don't have the Things to do it = myself:) What else do I need? It will be a good learning experience for = the rest.
Buly

On Sep 8, 2005, at 3:39 PM, = Mark R Steitle wrote:

Ed,

I wrote up = step-by-step instructions a while back on converting an ND alternator = from internal regulator to external.=A0 If anyone is interested, let me = know and I will send it to them directly.=A0 This conversion makes it so = that you can shut the thing down by cutting the power to the field wire = as is the method used by the Perihelion Design OVM.=A0

Mark S.=A0

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline= .net] Ed = Anderson
Thursday, = September 08, 2005 2:24 PM
To: Rotary motors in aircraft
[FlyRotary] Re: = Overvoltage control (help Ed A)=A0=A0On alternators = with internal regulators (most Auto alternators), breaking the low = current Field circuit may not (will likely not) stop the alternator from = producing current.=A0 Most of the alternators need the field coil = current to "bootleg" their start in producing voltage, but once = generating - do not need the external field coil current=A0to continue.=A0= That is why if you have an alternator with an internal regulator, you = can not depend on opening the low current field coil circuit to kill the = power=A0and why you would need=A0a =A0method similar to the one = described in this thread of breaking the high current (Power lead = usually referred to as the "B" lead) through a high capacity relay = (Contactor) or a "fuse".

=A0

=A0

=A0

=

----- Original Message -----

WALTER B = KERR

Rotary motors = in aircraftSent: Thursday, September 08, 2005 2:14 PMSubject: [FlyRotary] Re: Overvoltage control (help Ed = A)=A0

=A0 If you don't = have a low current way to=A0break the field current, and need to break = the high current line, then you have to used this OV module to=A0trip a = breaker that's holding in a main contactor for your=A0high=A0current=A0"B"= lead. =A0

=A0

Rusty

=A0

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

Help Ed. I almost understand Rusty's comments, but Mark S = left me in the dust. Us old dogs are sometimes hard to = train!

I think that with an = internal regulator; just because you break the field current supply=A0, = a failed regulator=A0may keep powering the field with the internal = alternator voltage. The continous breaker in the big alternator line can = protect the battery and airplane except what happens to the alternator = in the meantime if the interal regulator is applying a large field = current to the field will the alternator burn up quiet rapidly and = possible start a fire?

=A0

Bernie, soggy = Treasure although we had a bonanza just taxi in so must be drying = out a little

=A0


= --Apple-Mail-2--274703816--