Return-Path: Received: from out011.verizon.net ([206.46.170.135] verified) by logan.com (CommuniGate Pro SMTP 4.2.4) with ESMTP id 455702 for flyrotary@lancaironline.net; Wed, 06 Oct 2004 22:26:13 -0400 Received-SPF: pass receiver=logan.com; client-ip=206.46.170.135; envelope-from=finn.lassen@verizon.net Received: from verizon.net ([4.12.145.173]) by out011.verizon.net (InterMail vM.5.01.06.06 201-253-122-130-106-20030910) with ESMTP id <20041007022541.DAHH14580.out011.verizon.net@verizon.net> for ; Wed, 6 Oct 2004 21:25:41 -0500 Message-ID: <4164A920.2030402@verizon.net> Date: Wed, 06 Oct 2004 22:25:36 -0400 From: Finn Lassen User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.4) Gecko/20030624 Netscape/7.1 (ax; PROMO) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: #$!%@$ temperatures still high References: In-Reply-To: Content-Type: multipart/alternative; boundary="------------050608000206000307000004" X-Authentication-Info: Submitted using SMTP AUTH at out011.verizon.net from [4.12.145.173] at Wed, 6 Oct 2004 21:25:41 -0500 This is a multi-part message in MIME format. --------------050608000206000307000004 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit I've heard 90, 100 or more volts. If you don't believe it and you have an alternator with an external voltage regulator, you could try feeding the field winding the full 12 volts, with the alternator running at full speed. Of course you might fry the diodes in the alternator in the process. Finn DaveLeonard wrote: > 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. > > 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. > > > > 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 > > > --------------050608000206000307000004 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit I've heard 90, 100 or more volts.

If you don't believe it and you have an alternator with an external voltage regulator, you could try feeding the field winding the full 12 volts, with the alternator running at full speed. Of course you might fry the diodes in the alternator in the process.

Finn

DaveLeonard wrote:

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.

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.

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

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