46 replies to this topic

[HB]

827Z-gJxskk

[VicHockeyFan]

Oh, boy. Some good old-fashioned good luck saved businesses around here.

[HB]

Oh, boy. Some good old-fashioned good luck saved businesses around here.

I think that the City crew saved the day by getting there in short order. They knew exactly where the shut off was unlike Oak Bay from what I remember of that one they could not find the shut off valve. I think the medical building at the corner was at the greatest risk. If you pause the video you can see its getting close to the door
The catch basins yesterday were blocked from all the rock and grass and debris that floated down the road.

Cheers to the Public works crews

[Baro]

See oak bay, Victoria does have something to offer in amalgamation: works crews who can turn off a water main in under a day!

[Bingo]

Victoria does have something to offer in amalgamation: works crews who can turn off a water main in under a day!

Have you ever tried to adjust the hot and cold water in a shower, and find out that it's plumbed backwards and the taps turn the opposite way.

Or does that only apply in the southern hemisphere?

[D.L.]

good work HB :-)

[VicHockeyFan]

That's a good video, HB, well done.

[LJ]

827Z-gJxskk

From about 1:04 forward what is the deal with the car in front of you and the flashing taillights? I have never seen them flash like that, is that peculiar to that car of is it some aftermarket install?

[VicHockeyFan]

Whoops...

[sebberry]

The van has his turn signal on. The Porsche Panamera has LED tail lights.

Time for a lesson? Good.

Alternators in vehicles produce AC voltage which must be turned into DC voltage. When you convert AC into DC, you don't get a steady flow of electricity, it "pulses".

This pulsing of electricity isn't noticeable on standard filament bulbs because they take too long to fade to off. By the time the next pulse of electricity comes along, the filament is still glowing.

LED's on the other hand stop emitting light virtually instantly, and when the voltage source is pulsing they're actually flashing on and off very rapidly. Too quickly for the eye to see, but it becomes out of sync with the refresh rate of a camera's sensor and produces flickering.

Sometimes cars will also use PWM, or Pulse Width Modulation to control the brightness of an LED. This PWM turns the LED on and off very quickly, but slow enough that you don't percieve the full brightness of the LED.

I think.

[Sparky]

^ You are 100 % correct. It's all the way the camera reproduces it at 25 frames per second. http://www.alfaowner...-giulietta.html

[HB]

You are both correct I shoot video at 60 fpm and all LED lights do that Including traffic lights at intersections.
Not visible to the bare eye but visible at 60fpm

[VicHockeyFan]

Hmmmmmmmm. I did not know that. I know that alternators convert AC to DC, but had not considered the pulse.

[sebberry]

http://www.expertsmi...7342873185.aspx

Anyway, since water and electricity don't mix, I should stop derailing this thread

[phx]

Hmmmmmmmm. I did not know that. I know that alternators convert AC to DC, but had not considered the pulse.

There is not much ripple from the alternator and it gets smoothed out by the battery.

The flickering LED would be from the electronics driving it.

[eseedhouse]

Alternators in vehicles produce AC voltage which must be turned into DC voltage. When you convert AC into DC, you don't get a steady flow of electricity, it "pulses".

It only pulses when it comes out of the diode. This is known as "ripple" but a properly designed rectifier will use an inductive choke to damp this out and leave virtually no ripple in the final output.

Most of the electrical pulsing that an automobile puts out comes from the points in the distributor, which are often poorly filtered. This can be bad if you are powering a RF transmitter directly from the electrical system and usually requires a choke between the battery and the transmitter. It's often a problem for Hams when they install a mobile transceiver.

[eseedhouse]

Your diagram is incomplete. Any competently designed rectifier will use an inductive choke (basically a coil of wire) to smooth out the ripple in the current that is there as it comes out of the diode. Also, in a car the battery acts as a reservoir that damps out the ripple.

[sebberry]

Meh.. It's a German car and Germans can't do electronics I'm sticking with my story

LED Christmas lights are another culprit. Scan your eyes across a string of LED lights and you'll see the flickr quite easily.

[Bingo]

In other words the emergency flashers were on.

[Sparky]

I heard on the Ocean news yesterday that the cause of the hydrant failure was still unknown. Rubbish.

Not only was HB the first to break the story here on Vibrant Victoria, his exposé was complete with diagnostics. Sheesh!

Nice work HB.