Return-Path: Received: from bree.pipcom.com ([204.92.62.3] verified) by logan.com (CommuniGate Pro SMTP 4.1) with SMTP id 2505460 for flyrotary@lancaironline.net; Mon, 28 Jul 2003 13:27:01 -0400 Received: (qmail 21620 invoked from network); 28 Jul 2003 17:26:41 -0000 Received: from ras3-33.pipcom.com (HELO new) (204.92.62.165) by bree.pipcom.com with SMTP; 28 Jul 2003 17:26:41 -0000 Message-ID: <005101c3552d$110f23c0$0b3cfea9@new> From: "Peter Cowan/Lexy Cameron" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: starters and solonoids Date: Mon, 28 Jul 2003 13:23:36 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_004E_01C3550B.737ED900" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 This is a multi-part message in MIME format. ------=_NextPart_000_004E_01C3550B.737ED900 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hello Dale. I'll comment in your text below: Please correct me if I am wrong, but from the description, it sounds = as though you have the following setup: Battery cable goes to contactor ("automotive: solenoid"); another = cable runs from contactor output to starter solenoid. "Start" circuit = energizes the contactor coil, closing high-current path to = starter/solenoid. When start signal is removed, starter continues to = spin. =20 [||B||]-----------(C)-------------(S)-(M) The latter case is generally because the contactor has stuck = "connected" (welded). If you want to prevent this from happening where = you can't get out and disconnect it, wire two contactors _in_series_ = with the start terminals in parallel, so that they are energized = simultaneously. =20 My first solution was as above with the contactor and the solonoid = activated together. This failed. [||B||]---------(C)--(C)-----------(S)-(M) Now, if either contactor sticks, the other will still break the = high-current circuit, and the motor will stop. Don't you actually have three "contactors" above: the solonoid is = also a contactor. Surely if two didn't work going to a third is not = worth it. As I see it the solonoid has a short that provides power from = voltage to its' contactor terminals to it's winding terminal. Since my = second contactor is in parallel with the solonoid windings this short = activates it as well. The probelm is resolved by not using the contactor = terminals on the solonoid but just using it to through the gear in. = Power from the first contactor goes to motor. BTW, back when I used to install Ford engines in strange places, I = always took care to mount the contactor with the coil UP, so that = gravity would work for me in opening the circuit, should the spring = fail. Dale -------------------------------------------------------------------------= ----- Bob: Yes, but come to think of it, IF the Mazda solenoid is just an = electrical contactor, not also a gear engagement mechanism (I don't = know), you could bypass the original solenoid altogether. =20 Oh-oh, my book indicates you have to use both. The original engages = the gear. =20 Bob Darrah Yes it does engage the gear so I did wire the two solonoids in = parallel on the activation wire but I disconected the battery cable from = its' normal input side of the mazda solonoid and put it on the side that = has the cable going to the motor. This way (I thought) no current is = going through the mazda solonoid contacts. In spite of my being = convinced this would solve the problem, I regret to say there is no = change: stays running after starter switch opened. So doesn't this have to mean that power is getting from the contacts = to the coil of the solonoid???. Peter -------------------------------------------------------------------------= ----- >> Homepage: http://www.flyrotary.com/ >> Archive: http://lancaironline.net/lists/flyrotary/List.html ------=_NextPart_000_004E_01C3550B.737ED900 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hello Dale.
I'll comment in your text below:

Please correct me if I am wrong, but from the description, it = sounds=20 as though you have the following setup:

Battery cable goes to = contactor=20 ("automotive: solenoid"); another cable runs from contactor output to = starter=20 solenoid.  "Start" circuit energizes the contactor coil, closing=20 high-current path to starter/solenoid.  When start signal is = removed,=20 starter continues to spin. =20

 [||B||]-----------(C)-------------(S)-(M)

The = latter case=20 is generally because the contactor has stuck "connected" = (welded).  If=20 you want to prevent this from happening where you can't get out and = disconnect=20 it, wire two contactors _in_series_ with the start terminals in = parallel, so=20 that they are energized simultaneously. 
 My first = solution was as=20 above with the contactor and the solonoid activated together. This=20 failed.
 

[||B||]---------(C)--(C)-----------(S)-(M)

Now, if = either=20 contactor sticks, the other will still break the high-current circuit, = and the=20 motor will stop.
 Don't you = actually have three=20 "contactors" above: the solonoid is also a contactor. Surely if two = didn't=20 work going to a third is not worth it. As I see it the solonoid has a = short=20 that provides power from voltage to its' contactor terminals to it's = winding=20 terminal. Since my second contactor is in parallel with the solonoid = windings=20 this short activates it as well. The probelm is resolved by not using = the=20 contactor terminals on the solonoid but just using it to through the = gear in.=20 Power from the first contactor goes to motor.
BTW, back when I used to install Ford engines in strange places, = I always=20 took care to mount the contactor with the coil UP, so that gravity = would work=20 for me in opening the circuit, should the spring=20 fail.

Dale

 
Bob:
Yes, but come to think of it, IF the Mazda = solenoid is=20 just an electrical contactor, not also a gear engagement mechanism = (I don't=20 know), you could bypass the original solenoid altogether. =20
 
Oh-oh, my book indicates you have to use both. = The=20 original engages the gear. 
 
Bob Darrah
 
Yes it does engage the gear so I did wire the = two=20 solonoids in parallel on the activation wire but I disconected the = battery=20 cable from its' normal input side of the mazda solonoid and put it = on the=20 side that has the cable going to the motor. This way (I thought) no = current=20 is going through the mazda solonoid contacts.  In spite of my = being=20 convinced this would solve the problem, I regret to say there is no = change:=20 stays running after starter switch opened.
So doesn't this have to mean that power is = getting from=20 the contacts to the coil of the solonoid???.
Peter

>>  Homepage: =20 http://www.flyrotary.com/
>>  Archive:  =20 = http://lancaironline.net/lists/flyrotary/List.html
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