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                           AeroElectric-List Digest Archive
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                     Total Messages Posted Fri 09/09/22: 1
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Today's Message Index:
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     1. 08:08 AM - Re: Ground power  (fasilpereira)
 
 
 
________________________________  Message 1  _____________________________________


Time: 08:08:52 AM PST US
Subject: AeroElectric-List: Re: Ground power
From: "fasilpereira" <fasilpereira@yahoo.com>



>  Incorporation of the Cole-Hersee, ground
>    vehicle power connector was a compromise
>    in favor of much lower, simpler cost.
> 
>    Recall also that many installations of
>    the C-H connector on aircraft did not
>    include a pilot operated ground power
>    contator (as explained in my article
>    of some years back).
> 
>    The contactor center pin was simply
>    hardwired to the ships bus structure.
>    This is lead to an incident I cited
>    when departing Kansas City on a very
>    cold morning. The ground power operator
>    had his back turned to me while dumping
>    28v into my 14v airplane.
> 
>    Lack of pilot control opened a door
>    for the ov event I experienced. It also
>    made for erosion of the center pin on
>    FBO ground power cables AND customer
>    ground power jacks when the connector
>    was mated/demated under load.


Bob and others,

Im considering installing a C-H connector on my aircraft to be used in case of
difficulties during engine start. The plan is to build a cable with a male C-H
connector and jaws clamps and keep it in the aircraft.

Here in Brazil it is virtually impossible to find an FBO with a 12V power cart
and the 24V ones always have the 3-pin connectors. So if I ever use this cable,
that will be plugged to a 4-wheeled vehicle and Ill have to be the one doing
it.

That being said, Im considering hardwiring the C-H connector directly to the Battery
Master relay and skip all the other relays and diodes, in favor of simplicity,
weight and cost.

Do you see any other downsides on this setup other than the risk of reversed polarity
(I dont think Ill do that mistake), wrong voltage (there is no 24V ground
power available with a C-H connector in the country) or connector erosion (It
is not going to be a problem because it wont be used frequently)?

Thank you,

Fabricio

--------
Fabricio Pereira
Engineer / Pilot


Read this topic online here:

http://forums.matronics.com/viewtopic.php?p=507867#507867


 

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