Today's Message Index:
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1. 08:48 AM - Re: OVM-14 question (jdpnm)
2. 06:25 PM - Re: HomeBrew Engine Monitor (andymeyer)
Message 1
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| Subject: | Re: OVM-14 question |
I choose the Z13/8 instead of the Z12 because I have electrical dependent fuel
and ignition. The Z13 seemed closest to my configuration using the Ford regulator
rather than the B&C regulator.
The design concept is based on the article listed below. I wanted to have continuous
flight with least amount of pilot intervention.
>From "Electrical System Reliability 04/00
Adding an Aux alternator with auto switching
In normal flight both alternators are ON but the Aux alternator goes to sleep because
it's regulator thinks the bus voltage is too high. If the main alt fails
to support the ships loads, the bus voltage sags waking up the Aux Alt.
Reason I have circuit breakers on some items is because with a momentary switch,
I can short to ground items to lighten load, which will trip the breakers reducing
loads. Then if appropriate I can return function to selected items as the
situation permits, By resetting the individual CB.
Cost fuse vs CB is not an issue as I have the CB already. Im also using circuit
breaker switches for some items and fuse for some other items.
My main question is how to get over voltage protection to work individually for
each alternator. It would seem that if one alternator went high it would trip
both field breakers. I think I need to monitor each output before it guts to
the buss. However I could just let it trip both field breakers and the reset on.
if it trips again reset the other. but that requires more pilot intervention.
Any reason a low voltage warning light cant be installed with a resistor of of
the terminal I of the ford regulator? I think that is what ford does.
> I'm doing 2 electrical energized field alternators (small frame 53A), one adjustable
regulator, one non adjustable regulator, 2 OVM-14 modules, one battery
off the Z13/8 dwg.
If you have two, hefty alternators then
Z12 is the better option.
> I have two 5 amp Klixon circuit breakers for the fields.
Okay
> My question is about the OVM-14. If both alternators were in output mode due
to low voltage then one went into over voltage, how do I get the OVM-14s to only
trip the circuit for the one that is over voltage? It seems like both field
circuits would trip the CB.
You don't run both alternators at the same time.
Run only the main alternator until you get a
low volts warning then turn main alternator
OFF, aux alternator ON>
> Second question is about eBus.
>
> I have Circuit breakers for many things. Instead of a second bus, I was thinking
of a momentary switch connected to the load side of all things that could
be shut off in battery saving mode. Pressing the switch would trip the breakers
for unnecessary items which could be individually turned back on if required.
would a switch be adequate or should a 704-1 relay be used to handle the shorting
load.
I'm curious as to why Z12 is un-attractive as-published?
What shortcomings in Z12 beg rectification?
Also, aside from crow-bar field breakers, why
not fuse blocks? Breakers take up space, add
a lot of fabrication/installation labor, don't
work any better than a fuse. 99.9% of all breakers
installed at the factory go to the scrap yard
never having been required to keep a wire from
smoking. Why so much investment in a feature
that adds nothing to the utility/reliability
of your airplane?
Bob . . .[/quote]
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=493716#493716
Message 2
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| Subject: | Re: HomeBrew Engine Monitor |
Well Bob, That's the funny thing. I got so frustrated at the schematic tools that
I skipped that step, but I'll go back to it 'cause I know it's the right thing
to do. Let me see if I can get something that's understandable.
Andy
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=493719#493719
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