Return-Path: Received: from [216.52.245.18] (HELO ispwestemail2.mdeinc.com) by logan.com (CommuniGate Pro SMTP 4.2.4) with ESMTP id 456021 for flyrotary@lancaironline.net; Thu, 07 Oct 2004 07:17:08 -0400 Received-SPF: none receiver=logan.com; client-ip=216.52.245.18; envelope-from=wschertz@ispwest.com Received: from 7n7z201 (unverified [67.136.146.16]) by ispwestemail2.mdeinc.com (Vircom SMTPRS 3.2.315.0) with SMTP id for ; Thu, 7 Oct 2004 04:16:35 -0700 Message-ID: <018f01c4ac5f$19c5a3b0$c6918843@7n7z201> From: "William" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: #$!%@$ temperatures still high Date: Thu, 7 Oct 2004 06:16:30 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_018C_01C4AC35.2F730DD0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1437 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1441 This is a multi-part message in MIME format. ------=_NextPart_000_018C_01C4AC35.2F730DD0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable If a voltage regulator fails, how high can the voltage go? Way higher than 28 volts -- fellow here at the airport bought an RV-6, = and on the way home the VR failed, voltage rose to where it was frying = all the guages and power supplies to GPS and Xponder. He put in the = Aeroelectric (B&C) OV protection circuit after that, and on restart the = Circuit breaker popped, traced it down to a bad ground in the circuit to = the VR. Plane had flown significant hours before this happened. Bill Schertz KIS Cruiser # 4045 ----- Original Message -----=20 From: DaveLeonard=20 To: Rotary motors in aircraft=20 Sent: Wednesday, October 06, 2004 6:57 PM Subject: [FlyRotary] Re: #$!%@$ temperatures still high Al, you are right about now having the lack of over-voltage = protection. All I have in line is a fusable link rignt now. = Fortunately, all of my expensive avionics can tolerate voltages of at = least 28V without being affected. =20 If a voltage regulator fails, how high can the voltage go? Dave Leonard Dave; That's interesting. Makes me wonder whether I should put a scope on = voltage and see if it is smooth. =20 The downside of connecting the field to the output, as I'm sure you = know, is that you now have the risk of a runaway voltage condition if = the VR fails. I guess the odds are low, but the costs could be high. = Avionics? I assume that you have a breaker (or fuse) in the alt field circuit. = You can put a "crowbar" circuit between the field lead and ground that = will trip the breaker in an over-voltage condition. I got one from = Aeroelectric. Al ------=_NextPart_000_018C_01C4AC35.2F730DD0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
If a voltage regulator fails, how high can = the voltage=20 go?
 
Way higher than 28 volts -- fellow here at = the airport=20 bought an RV-6, and on the way home the VR failed, voltage rose to where = it was=20 frying all the guages and power supplies to GPS and Xponder. He put in = the=20 Aeroelectric (B&C) OV protection circuit after that, and on restart = the=20 Circuit breaker popped, traced it down to a bad ground in the circuit to = the VR.=20 Plane had flown significant hours before this=20 happened.
Bill Schertz
KIS Cruiser # 4045
----- Original Message -----
From:=20 DaveLeonard=20
Sent: Wednesday, October 06, = 2004 6:57=20 PM
Subject: [FlyRotary] Re: #$!%@$ temperatures still high

Al, you are right about now having the lack = of=20 over-voltage protection.  All I have in line is a fusable link = rignt=20 now.  Fortunately, all of my expensive avionics can tolerate = voltages of=20 at least 28V without being affected. 
 
If a voltage regulator fails, how high can = the=20 voltage go?
 
Dave Leonard

Dave;

 

That=92s interesting.  = Makes me=20 wonder whether I should put a scope on voltage and see if it is=20 smooth. 

 

The downside of connecting = the field=20 to the output, as I=92m sure you know, is that you now have the risk = of a=20 runaway voltage condition if the VR fails.  I guess the odds = are low,=20 but the costs could be high. Avionics?

 

I assume that you have a = breaker (or=20 fuse) in the alt field circuit.  You can put a =93crowbar=94 = circuit=20 between the field lead and ground that will trip the breaker in an=20 over-voltage condition.  I got one from = Aeroelectric.

 

Al

 

------=_NextPart_000_018C_01C4AC35.2F730DD0--