X-Virus-Scanned: clean according to Sophos on Logan.com X-PolluStop-Diagnostic: (direct reply)\eX-PolluStop-Score: 0.00\eX-PolluStop: Scanned with Niversoft PolluStop 2.1 RC1, http://www.niversoft.com/pollustop Return-Path: Received: from tomcat.al.noaa.gov ([140.172.240.2] verified) by logan.com (CommuniGate Pro SMTP 4.3c4) with ESMTP id 860426 for flyrotary@lancaironline.net; Thu, 07 Apr 2005 11:30:36 -0400 Received-SPF: none receiver=logan.com; client-ip=140.172.240.2; envelope-from=bdube@al.noaa.gov Received: from mungo.al.noaa.gov (mungo.al.noaa.gov [140.172.241.126]) by tomcat.al.noaa.gov (8.12.11/8.12.0) with ESMTP id j37FTejB005634 for ; Thu, 7 Apr 2005 09:29:45 -0600 (MDT) Message-Id: <6.2.1.2.0.20050407091849.03503840@mailsrvr.al.noaa.gov> X-Mailer: QUALCOMM Windows Eudora Version 6.2.1.2 Date: Thu, 07 Apr 2005 09:29:16 -0600 To: "Rotary motors in aircraft" From: Bill Dube Subject: Re: [FlyRotary] Re: Timing In-Reply-To: References: Mime-Version: 1.0 Content-Type: text/html; charset="us-ascii" At 10:37 PM 4/6/2005, you wrote:

In a message dated 4/6/2005 7:54:16 PM Pacific Standard Time, lors01@msn.com writes:

The RX-8 sensor is magnetic reluctance. Same type, size & shape as the 3rd gen. In fact if you have a 3rd gen sensor, you can use it if you can mount it correctly. The Subaru sensors will also work but they are poor quality (many failures reported) so don't go there.

Tracy, I hope you know the answer to this question. Does the reluctance type sensor need a magnetic wheel to work? If the sensor has the magnet and a coil of wire might the pulse be made by any electrically conductive material? I am not an EE, rather a ME so I may be showing my "little bit of knowledge" but if I remember the theory you should just need a conductor to "cut" the line of magnetic flux. The use of a aluminum tooth wheel wouldn't save much weight but it would be nice to not have to paint it to prevent rust!

Magnetic reluctance sensors need a steel "tooth" on the moving disk to operate. The tooth (or teeth) must be a material that you can pick up with a magnet. Thus, aluminum won't do. You could put a steel "ring gear" on an aluminum pulley, I suppose.

The sensor has a magnet inside. When the tooth comes near, it makes an easier path for the magnetic field from the sensor magnet. (Kind of like putting the keeper on a horseshoe magnet.) This increases the magnetic field in the sensor pick-up coil, generating an electric current. This voltage "pip" is sensed by the electronics.