Mailing List lml@lancaironline.net Message #32669
From: Bob B. <rbelshe@comcast.net>
Sender: <marv@lancaironline.net>
Subject: RE: [LML] Re: Lancair 320 gear problem -- help wanted
Date: Thu, 03 Nov 2005 13:49:24 -0500
To: <lml@lancaironline.net>
Great experiment, Scott.  
 
I would expect that the pump would just get hot if you powered both leads.   It might trip the breaker if you held power on long enough. 
 
Did you really get the pump to run in the "wrong" direction some of the time?  You said  "at least six sequential connections to both wires were made separated by a second or so (Dn-Up, Up-Dn) and all but one resulted in the pump running primarily in the down direction with foaming visible in the up direction tube.."  Do you mean the pump keeps running when you connect 12v to the "other" wire?  Do you mean it starts in one direction and then reverses when you connect the second wire?
 
If the pump ever runs in the wrong direction it would open the wrong pressure switch and never shut down!   
Does anyone know how this motor is wound?  I think it is probably a series motor with two field windings.  It should be impossible to do what you reported.
 
Also, it has been noted that the motor relays are Ford starter relays.   In automotive service they would be starting and interrupting over ten times the current they see in our application.  Fusing of the contacts should be a rare (if ever, occurrence).   In the instance where relay power is left on for a long time they could stick in the closed position due to an internal melt down of some sort.
 
Thanks again for your experiment, and all the good info you provide this group.   Please don't take this as criticism. 
Like you, I'm just trying to understand why people have so many problems with the LNC2 gear system. 
Fortunately, I have had none, except for a blown seal and a leaky (in one direction only) dump valve.
 

Bob Belshe
Moraga, CA
Lancair 235/320  
http://home.comcast.net/~rbelshe/

 
 



 
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