chain of events

In article ,
Mike 'Flyin'8' wrote:

UPS's don't need time to "Kick In" That is why thet are called
UnInteruptable Power Supplies.

UPS are usually designed to come online within a couple of cycles.

I have never seen a UPS that takes more than a fraction of a cycle to
transition to backup mode. In fact, units which are used in "mission
critical" applications are not the line interactive type as you seem
to be thinking about above, instead are dual online conversion. I
would assume that a UPS used for ILS equipment and radio
communications for ATC would be a mission critical design as opposed
to the less than reliable line interactive design. The dual online
conversion types are actually running off battery and an oscillator
all the time. There is no switching time.

But hey... What do I know...



Mike Alexander
PP-ASEL
Temecula, CA
See my online aerial photo album at
http://flying.4alexanders.com

On Fri, 09 Mar 2007 17:48:01 -0800, Mike 'Flyin'8'
wrote:

In article ,
Mike 'Flyin'8' wrote:

UPS's don't need time to "Kick In" That is why thet are called
UnInteruptable Power Supplies.

UPS are usually designed to come online within a couple of cycles.

I have never seen a UPS that takes more than a fraction of a cycle to
transition to backup mode. In fact, units which are used in "mission
critical" applications are not the line interactive type as you seem
to be thinking about above, instead are dual online conversion. I
would assume that a UPS used for ILS equipment and radio
communications for ATC would be a mission critical design as opposed
to the less than reliable line interactive design. The dual online
conversion types are actually running off battery and an oscillator
all the time. There is no switching time.

But hey... What do I know...

There are also "bridge" UPSes that store energy in flywheels and
ultracapacitors.

Don

There are also "bridge" UPSes that store energy in flywheels and
ultracapacitors.

I'm no UPS or Power engineer, but isn't the flywheel bridge used to
"bridge" the time it takes for a generator to come online. I was not
aware that there are UPS's using this technology. While ultracaps do
store energy, they are typically only sized to maintain an output load
for a period of about 30 seconds in the flywheel bridge. This
application isn't really a UPS per se, though would be awesome to
prevent the failure Capt Doug speaks of. My specialty isn't UPS's,
rather telecom, so take it all with a grain of salt.

Reading Capt Dougs story makes one wonder about the reliability of the
"things" we rely on for our navigation, communications etc while
flying around. I am a new pilot and would be kinda bummed out if on
final at night and the runway lights went out. Though I probably
shouldn't be, I think I am dependent upon the runway edge lighting to
make a landing at night... Maybe I am wrong... but dang that would be
an eye opener for sure if those things went out on me while on short
final, or even worse, just seconds before touchdown.

Mike Alexander
PP-ASEL
Temecula, CA
See my online aerial photo album at
http://flying.4alexanders.com

There are also "bridge" UPSes that store energy in flywheels and
ultracapacitors.

I'm no UPS or Power engineer, but isn't the flywheel bridge used to
"bridge" the time it takes for a generator to come online. I was not
aware that there are UPS's using this technology. While ultracaps do
store energy, they are typically only sized to maintain an output load
for a period of about 30 seconds in the flywheel bridge. This
application isn't really a UPS per se, though would be awesome to
prevent the failure Capt Doug speaks of. My specialty isn't UPS's,
rather telecom, so take it all with a grain of salt.

Reading Capt Dougs story makes one wonder about the reliability of the
"things" we rely on for our navigation, communications etc while
flying around. I am a new pilot and would be kinda bummed out if on
final at night and the runway lights went out. Though I probably
shouldn't be, I think I am dependent upon the runway edge lighting to
make a landing at night... Maybe I am wrong... but dang that would be
an eye opener for sure if those things went out on me while on short
final, or even worse, just seconds before touchdown.

Mike Alexander
PP-ASEL
Temecula, CA
See my online aerial photo album at
http://flying.4alexanders.com

I don't know whether a lot of the original story was tongue-in-cheek, or
whether it just got-a-little-better with each retelling; but I really can
not believe the part about the nav-aids going off line.

Basically, the runway and taxiway lighting systems need a lot of power, so I
would not be able to categorically deny any assertion. There are a lot of
budgetary and philosophical considerations involved, so a compromise between
cost and downtime is plausible--maybe even probable.

However, the nav-aids (localizer, glideslope, and marker beacons) require
very little power at each location--probably less than a personal computer.
And a TVOR requires very little more; so, like several others, I am willing
to postulate that the story, as told, is false.

Peter
Just my $0.02

On Fri, 09 Mar 2007 19:52:39 -0800, Mike 'Flyin'8'
wrote:


There are also "bridge" UPSes that store energy in flywheels and
ultracapacitors.

I'm no UPS or Power engineer, but isn't the flywheel bridge used to
"bridge" the time it takes for a generator to come online. I was not
aware that there are UPS's using this technology. While ultracaps do
store energy, they are typically only sized to maintain an output load
for a period of about 30 seconds in the flywheel bridge. This
application isn't really a UPS per se, though would be awesome to
prevent the failure Capt Doug speaks of. My specialty isn't UPS's,
rather telecom, so take it all with a grain of salt.

Reading Capt Dougs story makes one wonder about the reliability of the
"things" we rely on for our navigation, communications etc while
flying around. I am a new pilot and would be kinda bummed out if on
final at night and the runway lights went out. Though I probably
shouldn't be, I think I am dependent upon the runway edge lighting to
make a landing at night... Maybe I am wrong... but dang that would be
an eye opener for sure if those things went out on me while on short
final, or even worse, just seconds before touchdown.


Check out Pentadyne.com and activepower.com for flywheels.

Don

Mike 'Flyin'8' wrote:

While ultracaps do
store energy, they are typically only sized to maintain an output load
for a period of about 30 seconds in the flywheel bridge. *This
application isn't really a UPS per se

Why not? As long as those 30 seconds suffice to e.g. get said generator
online, the system serves to maintin power in the event of a utility power
failure, making it an uninterruptible power supply.

Which part of UPS don't I get?

Anno.

While ultracaps do
store energy, they are typically only sized to maintain an output load
for a period of about 30 seconds in the flywheel bridge. This
application isn't really a UPS per se

Why not? As long as those 30 seconds suffice to e.g. get said generator
online, the system serves to maintin power in the event of a utility power
failure, making it an uninterruptible power supply.

Which part of UPS don't I get?

Anno.

The "U" part.

Uninteruptable means you never miss a cycle, the light bulbs never blink,
etc.

Uninteruptable supplies are now cheap for small systems and available, but
costly, when aplied on a grand scale. What you descrbed is a backup or
standby generator with automatic changeover.

If you think of the situation that the passengers might see inside the
terminal, most of the lighting and possibly the schedule monitors would be
backed up by the standby generator--because there are enough battery powered
emergency lights to prevent panic and/or injuries. OTOH, the computers
which drive the monitors would be on UPS. Today, most of the monitors would
probably be on UPS as well, since it is no longer expensive to do so--and
probably contributes to calm amoung the public in the terminal.

Peter

Peter Dohm writes:

If you think of the situation that the passengers might see inside the
terminal, most of the lighting and possibly the schedule monitors would be
backed up by the standby generator--because there are enough battery powered
emergency lights to prevent panic and/or injuries.

Do power failures normally cause panic?

--
Transpose mxsmanic and gmail to reach me by e-mail.

Mxsmanic wrote:
Peter Dohm writes:

If you think of the situation that the passengers might see inside the
terminal, most of the lighting and possibly the schedule monitors would be
backed up by the standby generator--because there are enough battery powered
emergency lights to prevent panic and/or injuries.

Do power failures normally cause panic?

New York City, 1977
West Coast of USA, 1996

Mike 'Flyin'8' wrote:


UPS are usually designed to come online within a couple of cycles.


I have never seen a UPS that takes more than a fraction of a cycle to
transition to backup mode.


We have UPS's in the tower and TRACON. They work only when properly
maintained. Ours are not and it's a 50/50 bet that the entire
tower/TRACON will reset when they don't work. If they don't work it's a
10-15 second deal while everything comes back on line. That's why we
always manually turn on the back up generators whenever there are
thunderstorms in the area.




In fact, units which are used in "mission
critical" applications are not the line interactive type as you seem
to be thinking about above, instead are dual online conversion. I
would assume that a UPS used for ILS equipment and radio
communications for ATC would be a mission critical design as opposed
to the less than reliable line interactive design.

They are not.