gmcjetpilot
Joined: 04 Nov 2006
Posts: 170
|
 Posted: Wed Jan 24, 2007 9:41 am Post subject: alternators in aircraft (yes) OV module (no?) |
 |
|
>I have a IR ALT from Plane Power (14v) and am
| Quote: | wiring per your book. Can I use the LR3C from
B&C to prevent OV problems? Or, does
someone else sell such a device?
Thanks, David Weber
|
Dave: You don't need anything. You DO not need
the LR3C (which is a voltage regulator for and
externally regulated alternator), nor do you need
Bob's OV protection add-on for internally
regulated alternators. Unlike Bob's OV protection
the Plane Power protection is included in and
incorporated inside the alternator. The little module
on the back monitors the voltage and will CUT
OFF POWER to the voltage regulator (which
removes power to the FIELD, rotor). That will
smoothly and safely shut down the alternator with
out any load dump. Bob's set up is external
to the alternator and requires you to put a large
relay to break or cut the output, ie B-lead. It does
not shut the alternator down it just disconnects it.
You have the best of the best, relax.
| Quote: | From: Robert L. Nuckolls, III <nuckollsr(at)cox.net (nuckollsr(at)cox.net)>
Over the past week or so I've become aware of
two more incidents of uncontrolled OV
conditions arising from the failure of internally
regulated alternators.
|
Bob could you give any details? Since 14.3 volts to
14.5 volts is normal any thing over that is Over
Voltage. Are we talking 14.6 volts.
I respect that you demand repeatable test,
facts, proof and data. What happened? How
severe was this OV?
If it a typical OV anomaly or failure it was may
be 16 volts, max. What say you Bob?
When you throw out little info like that you
feed fear from ignorance from lack of info. It
severs no one except if you want to support
the contention that I-VR are infior or not
suitable for planes, which is not true of
course. I-VR have and outstanding reliability
rate and OV is not an issue. Unfortunately
Van was selling a crop of units from a dubious
supplier which created a reliability issue but
no major OV event. Again 1000's are sold
every year for aircraft use and Van's gets only
a small % back that they sell, and they sell a lot.
What are the details. I understand "I've
become aware", but if the OV was mild as
most are.
DO WE NEED TO HAVE OV MODULES ON
TOP OF I-VR? Especially for VFR planes.
As has been point out before most modern
electronics, avionics, even experimental "Glass"
and hand held GPS operate on 10-32 volts all
day and have 60 volt surge or spike protection.
Bob, looks good, but there is a product out already.
Not to steal you thunder but there is already an
existing OV module that will operate a BIG
Relay/Contactor for OV protection. It is by
perihelion-designs:
http://www.periheliondesign.com/lovm.htm
It looks like it does the same thing, open power to
the OV relay (contactor) if an OV is detected.
I appreciate Bob's effort to improve the "crow bar"
method. The new method is no longer a crow bar
and does not require a short to trip a circuit breaker.
That is good. The end result is still the same, OPEN
a big relay to cut the B-lead. I also appreciate the
disclaimer that disconnecting the alternator while
operating normally could damage it. Glad you
agree with Van and you owe him an appology for
calling him ignorant when he said the same thing.
My suggestion for all of those who fear OV, which
I think is way overblown, more than it should be,
consider the Plane Power Alternator.
Van's aircraft sells them or you can buy them
direct from Plane Power.
http://www.plane-power.com/
By the time you buy and alternator and add on OV
modules you will be better off, money, weight and
complexity with the Plane Power's unit. This company
takes the BEST possible NEW aftermarket parts
available (Nippon Denso) and modifies the fan for
proper CCW rotation, puts "aerospace" brushes on it for
low humidity operations. Of course it re-wires the
internal voltage regulators (power source) so it can be
OPENED or cut-off power with the miniature OV
module on the back. This was not easy but PP did it.
The plane-pwr OV module does a similar function as
Bob's and perihelion-designs, it cuts power at a set
voltage, but instead of a big relay is elegantly cuts
power INTO the alternator not out. It does not need a
big external relay and is all self contained. You don't
want another mechanical BIG RELAY in your system.
The module is a miniature of what Bob is proposing
and what perihelion-design is. The BIG difference
is Bob is trying to switch OFF, up to 60 amps and
at least 14.5 volts. The Plane power is dealing with
the FIELD which only draws at most 5 amps. Once
the field is cut off the alternator will produce no power.
Example: It's like stopping a car by letting off the
gas on a slight up-slope Vs. running full speed into
a wall. The cutting off the B-lead under full gallop
is the wall scenario. They both stop you but one
is going to leave a mark, ouch and may result in
sparks and flames.
Again OV with ND's has been shown to be rare
and mild. Van's aircraft has sold 100's a month
and there are 1000's out there on planes (not to
mention Millions of cars) and the problems are rare
and mild. So before you get excited and ADD stuff
onto your ND, consider the COST vs. GAIN. The
relay, wires, connectors add weight, cost and
maintenance issues. A nuisance trip will destroy
your alternator and Van's does not guarantee it.
Cheers George
Be a PS3 game guru.
Get your game face on with [url=http://us.rd.yahoo.com/evt=49936/*http://videogames.yahoo.com]the latest PS3 news and previews at Yahoo! Games.[/url] [quote][b]
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
