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Date: Wed, 27 May 2009 16:29:12 -0400
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Subject: Re: [LML] Re: Gear Relays are not working
From: Clark Baker <bakercdb@gmail.com>
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David,
Any thoughts on point #1 (the 50A breaker)?

(on all of my relays I am using the Blue Sea ones).


On Tue, May 26, 2009 at 4:22 PM, John Cooper <snopercod@citcom.net> wrote:
> Good comments so far by several responders. My personal additions:
>
> 1. A 50A circuit breaker specified in the plans will in no way protect yo=
ur
> hydraulic pump from burning up should the rotor lock up, neither will it
> protect your #10 pump wiring from burning up in the event of a fault. Thi=
s
> error by the factory dates back to the very first kit in 1986(?), and AFA=
IK,
> Lancair has never corrected it. The Oildyne pump draws maybe ~15 Amps whe=
n
> the gear are in motion, which spikes up to ~30 Amps just before the press=
ure
> switch stops the pump. A 50 Amp circuit breaker will take roughly 3 minut=
es
> to trip with 100 Amps flowing through it. Think about that.
>
> If you insist on using a circuit breaker, 30A would be better, but still
> won't protect you from smoke in the cockpit should your pump lock up. (A =
30A
> or 40A Maxi-Fuse offers better protection.)
>
> 2. Yes, connect the control power circuit breaker downstream of the main
> circuit breaker for the hydraulic pump. That way, the relays can't stay
> energized when the main CB (or fuse) is open.
>
> 3. =A0I recommend high-reliability 75A Bosch Relays for the hydraulic pum=
p,
> not the crap that the factory provided. (see details and part numbers pos=
ted
> here sometime during the last year).
>
> 4. Yes, use the back-to-back diodes to feed your "gear transition light".
> (See the schematic I posted here a few months ago). I used a red/green LE=
D
> which shows red when the hydraulic pump is running in either direction, a=
nd
> green when the nose gear door is closed.
>
> 5. Lance was a true genius when it came to aerodynamics, aesthetics, and
> business, but he didn't know diddly about electricity.
>
> --
> For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.ht=
ml
>


--=20
Clark Baker

mobile: + 1 917 558 5567


bakercdb@gmail.com