Yes, such as the Flaming River Industries Big Switch or the Hella with the
detachable key.
Interestingly enough, the Big Switch with a Bowden cable actuator is about
the same price
as the ciitech relay. Can't argue about the current drain; I wonder what
the weight differential
is?
Hooray for experimental aircraft! Endless hours of mucking about...
Shaun Simpkins
----- Original Message -----
From: "Steve Hagar" <hagargs@earthlink.net>
Subject: Re: Low-hold-current contactors and All-electric
panel examples
>
> Shaun:
>
> You can go with a zero amp manual disconnect switch. Summit Racing has
> about 5 different models of this type item for race cars etc. Dave and
> Terry have a nice installation of this type on their aircraft.
>
> Steve Hagar
> A143
> Mesa, AZ
>
> > [Original Message]
> > From: Shaun Simpkins <shauns@hevanet.com>
> > Date: 1/11/03 4:16:43 AM
> > Subject: Low-hold-current contactors and All-electric
> panel examples
> >
> > All:
> >
> > Jim Nelson and a few others excepted, the XS cowl can't nicely fit a
> standa> > rd "big"
> > front-mounted alternator, so past "all-electric airplane" threads on
this
> > the possibility of a B&C SD-8 or SD-20 on the vac. pad PTO as a
secondary
> > The Rotax-supplied alternator is of small capacity - 18A less
> > whatever the fuel pumps and ECU computer draw - and the vac. pad RPM is
> slo> > wer than
> > Lycoming standard, so an SD-8 is derated to about 5A and an SD-20 to
> about > > 12A. So good
> > "amperage conservation" needs to be practiced.
> >
> > An annoyance is the 1A holding current of the battery contactor relay,
> whic> > h represents appx. 8%
> > of the net Rotax alternator capacity. If you choose to implement a
fully
> r> > edundant system, with
> > dual batteries and alternators, you'll have at least 2 battery
> contactors, > > plus crossfeed contactors,
> > so this drain can add up fast. Although one can use manual contactors (
> as> > Tony K. did for
> > a while ) - possibly remotely activated via a Bowden cable - an
> alternative> > is a power-managed
> > contactor, one example of which is the cii technologies EV-200
> > http://www.ciitech.com/doc_generator.asp?doc_id1280
> > This product was designed for battery-powered vehicles, can switch 200A
> > and has a solenoid power-management circuit, which drops the hold
current
> > actuator to 130mA - an 8:1 reduction from a conventional contactor
relay,
> a> > nd possibly low enough to be insignificant. It is highly reliable,
> > lightweight, and an easy retrofit to a standard power system.
> Unfortunatel> > y, it is a lot more expensive
> > than a conventional contactor relay - $75 instead of $15. But it may
> make > > sense if you don't want to go to
> > heroic (Bowden cable) lengths to control alternator loads.
> >
> > I caution that this product has not been certified for the aircraft
> market,> > nor have I actually tested it. But
> > it's a tantalizing idea for those builders who'd like to try something
> >
> > If you would like to see how the big boys do all-electric, check out the
> SR> > -22 Pilot's Operating Handbook
> > on the Cirrus Design website
> > http://www.cirrusdesign.com
> > Page 3-28 and Page 7-39 et. seq. are very interesting reading and a neat
> wa> > y of implementing a dual-alt
> > dual-bat dual-bus system without the need for a crossfeed switch. It's
> got> > Bob Nuckolls' name all over it,
> > but I don't think he was a part of its design. Warning: the POH is
320+
> p> > ages and a 2.8MB download.
> >
> > Shaun Simpkins
> > ...no longer building but still scheming...
>
>
> --- Steve Hagar
> --- hagargs@earthlink.net
>
>
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