Ft.Worth, Tx Tornado with Whelens Roaring in Background.

[Alasiren1977]

I dont think this has been posted here before, there is a good minute of the Whelens going off in Wail mode. Why they turned off while the tornado was still on the ground, i will never now!

http://www.youtube.com/watch?v=LWoCQ2Q8o2g

[uncommonsense]

Why they turned off while the tornado was still on the ground, i will never now!

http://www.youtube.com/watch?v=LWoCQ2Q8o2g

Because most sirens are not rated for continuous duty (Sentries being the exception). Mechanical sirens would overheat and fry their motors. With Whelens, the drivers will ultimately overheat from the constant current through them and blow.

[JasonC]

Why they turned off while the tornado was still on the ground, i will never now!

http://www.youtube.com/watch?v=LWoCQ2Q8o2g

Because most sirens are not rated for continuous duty (Sentries being the exception). Mechanical sirens would overheat and fry their motors. With Whelens, the drivers will ultimately overheat from the constant current through them and blow.

They shouldn't. Their drivers are rated for continuous duty. Most electromechanical sirens are also rated for continuous duty now. They were simply set off for their 3-minute alert cycle and the timer simply timed out, and they weren't reactivated (although they probably should have been)

[AllAmericanFE]

Whelen sirens need a rest period. When the guy that normally sets off the sirens was on vacation we had a tornado warning and the Columbus Fire Alarm Office set them off again right after they shut down. This caused a massive amount of driver and amp failures and cost the EMA about $150,000 to fix.

[Justin]

How are these drivers cooled anyway? I'm thinking some sort of heat sink would be used, but if they fail like that it says to me that the sink isn't big enough or there aren't enough of them.

Either way, it's a very serious design flaw and one that should be addressed as soon as possible. A failure like that is just simply unacceptable, tornado's don't wait for sirens to be sounded.

[Travis]

Hehe I remember that day. I actually was working out at Alliance Fort Worth and I heard both Vortex's on the property very clearly.

Most North Texas municipalities will only do one cycle during tornadoes. I guess they figure that if you haven't heard the sirens in the 5 minutes they've been activated for...you aren't going to hear them. They are for people outdoors, and I think that it was pretty evident what the emergency was that day.

[bwillcox]

That was an insane day.

I still remember Jory getting on the 88 repeater and saying this over the noise: "KJ5RM PRIORITY... TORNADO WARNING DALLAS COUNTY!

You hear that over your radio and your blood just goes cold, because you know the storm is going to Bring It.

Not too long after that my coworker Ben (who is also a ham and a spotter) and I were looking out the loading bay door at the rotation as it passed just north of downtown. Of course, the mighty Thunderbolts were roaring. Everywhere.

That was also the day I found out that the Bolt at DFR station 1 closest to work is a single tone The next closest to us (Station 18?) was a dual tone and you would occasionally hear that clearly.

[Alasiren1977]

Whelen sirens need a rest period. When the guy that normally sets off the sirens was on vacation we had a tornado warning and the Columbus Fire Alarm Office set them off again right after they shut down. This caused a massive amount of driver and amp failures and cost the EMA about $150,000 to fix.

Well that really isn't what Whelen is claiming on their product sheets then because they say that these sirens can go up to 15 to 30 minutes "continuous" on their battery packs. If they needed time to rest then I'm sure that would have not been said by the manufacturer.