Message-ID: <001301c0e70d$1bf66ea0$23e2c740@bill>
From: "William T Bartlett" <WTBARTLETT@prodigy.net>
To: <lancair.list@olsusa.com>
References: <20010527042236.AAA2811@pop3.olsusa.com>
Subject: re:Hydraulic pump circuit breaker LNC 2
Date: Sun, 27 May 2001 17:28:19 -0700
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>>>
The hydraulic pump is often fitted where, in flight, it is impossible to
reach the 50 amp circuit breaker fitted next to the pump.  
<<<

The power to the pressure switches should not come from the hyd pump
circuit. Those little bity wires wouldn't  be saved by a 50 amp breaker.
They should be on a separate circuit. I have a push pull 2 amp pull Off
breaker on that circuit and pulling it off keeps the pump motor from
being activated. If you are using fuses (which I wish I had) you can put a
switch in that circuit. If the presure switches are not activated, when you
are testing your gear freefall or the pressure switch sticks closed, the
pump motor won't be activated. Now if those cheap intermittant relays,
powering the pump, fail (stick closed - they also stick open) you need to be
able to kill the pump motor circuit. The
intermittent relays should be replaced with constant duty relays. They have
an additional benefit of consuming less current.
Bill N7WB.

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