chain of events

In article nk.net,
Dave S wrote:

I dont know about the approach itself, but the power issue is very
believable. If the main transformer for the whole place let go, its VERY
likely that it takes 10 or more seconds for the generator to get up and
running. Also, if I understand right, the generators dont serve the
entire airport, just select facilities and one or two main runways.

An approach system doesn't have a UPS?

--
Bob Noel
(gave up lookingn for a particular sig the lawyer will)

"Bob Noel" wrote in message
...
In article nk.net,
Dave S wrote:

I dont know about the approach itself, but the power issue is very
believable. If the main transformer for the whole place let go, its VERY
likely that it takes 10 or more seconds for the generator to get up and
running. Also, if I understand right, the generators dont serve the
entire airport, just select facilities and one or two main runways.

An approach system doesn't have a UPS?

The article said it took a few seconds to kick in.

An approach system doesn't have a UPS?

The article said it took a few seconds to kick in.

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

Generator power is another story. Typicall transfer times are
generally in the neighborhood of 10 seconds from a cold start to power
transfer.


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

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.

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

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.

Newps wrote:

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.

If you keep posting facts instead of idle speculation you're going to
ruin USENET.

"Mike 'Flyin'8'" wrote in message
...
An approach system doesn't have a UPS?

The article said it took a few seconds to kick in.

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

Generator power is another story. Typicall transfer times are
generally in the neighborhood of 10 seconds from a cold start to power
transfer.

So..was it really a UPS, or a backup generator? Remember, the story we got
was 2nd hand/anecdote.