X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from willowsprings.uwyo.edu ([129.72.10.31] verified) by logan.com (CommuniGate Pro SMTP 5.2.14) with ESMTPS id 3731309 for flyrotary@lancaironline.net; Wed, 24 Jun 2009 15:01:33 -0400 Received-SPF: none receiver=logan.com; client-ip=129.72.10.31; envelope-from=SBoese@uwyo.edu Received: from ponyexpress-ht2.uwyo.edu (ponyexpress-ht2.uwyo.edu [10.84.60.209]) by willowsprings.uwyo.edu (8.14.2/8.14.2) with ESMTP id n5OJ0KS0019004 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=FAIL) for ; Wed, 24 Jun 2009 13:00:51 -0600 (MDT) (envelope-from SBoese@uwyo.edu) Received: from Boesexps (172.26.4.5) by uwmail.uwyo.edu (10.84.60.199) with Microsoft SMTP Server id 8.1.375.2; Wed, 24 Jun 2009 13:00:33 -0600 From: sboese To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] DC/DC [FlyRotary] Re: Relay Woes Date: Wed, 24 Jun 2009 13:00:00 -0600 Message-ID: <19A8F88BF784410F869C2366BDC75500@gg.uwyo.edu> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_002A_01C9F4CB.AEB118B0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 In-Reply-To: Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 ------=_NextPart_000_002A_01C9F4CB.AEB118B0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable AC solid state relays can be constructed so that once they are turned, = they won't turn off until the load voltage is zero (zero-crossing). This can = be a good thing in that little or no noise is generated when switching off = at that time. The delay in switching off is often not a problem when the voltage crosses zero 120 times a second. With a DC load, it will never = turn off. =20 Steve Boese ------=_NextPart_000_002A_01C9F4CB.AEB118B0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

AC solid state relays can be = constructed so that once they are turned, they won’t turn off until the load = voltage is zero (zero-crossing). This can be a good thing in that little = or no noise is generated when switching off at that time. The delay in switching off is often not a problem when the voltage crosses zero 120 = times a second. With a DC load, it will never turn off.

Steve Boese

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