Thunderbolt chopper observation.

[Mister_Penetrator]

I know this video was posted before. It is the first Thunderbolt 1003 on the WisconinSirens video list. How is it that when the siren shuts down, that the chopper stops suddenly, instead of continually winding down like other thunderbolts do? http://wisconsinsirens.com/sirenvideos.php

[Trey]

Most all Thunderbolts do that I believe. I'm just guessing by the noise that the blower cut off and the horn was turned away from the camera on wind-down. (If you turn the volume up you can hear it wind down still)

[Gil]

The blower gives the Thunderbolt most of its power.

The blower shuts off before the chopper completely winds down,
making it sound like it suddenly stops, but if you listen closely,
its still going.

[q2bman]

you also can hear when it fires back up the windup starts during the wind down. The pitch is higher the second test than when it strats on the first test. That chopper seems to spin more freely than other sirens i've heard. Causes a funky allert signal. long wind up and long wind down.

[cdvtripleseven]

Notice the sound volume drops off the same time the horn stops rotating.
The rotator motor and blower motor starters are kept energized by the time delay relay in the RCM. The chopper starter is energized when the timer or other control is turned on and deenergized when the timer or other control turns off. That siren's RCM time delay is set on about 6 seconds.

[AllSafe]

Yep, RCMs have an Agastat time-delay relay in them...they have a knob on top of them to set the delay and they keep the blower and rotator relays energized for as long as it is set for.