CLM Siren Rotation

[System 7000]

What speed did the CLM siren rotate at? There is a video on YouTube that shows it rotating very fast, but I can?t work out if the video shows a CLM rotating under its own power using its rotator, or if it is simply being pushed by hand.

I can hear a hum in the video, but I can?t work out if this is the rotator motor, some sort of other motor on the roof of the building (perhaps a ventilation unit), the camera itself, or just some ambient noise.

This video of the building on which the CLM was located being demolished seems to show the siren spinning as the building collapses, indicating that the rotator was not locked, and therefore could have been spun by hand.

I also can?t work out how fast the siren is rotating in the Tocsin B Exercise (I?m fairly certain that the siren is a CLM) ? I can?t establish how much of the variation in sound is caused by the rotation and how much is caused by the quality of the old recording. Does this siren sound as though it is rotating as fast as the one in the video?

Thanks for any replies!

Regards,
Jerry.

[System 7000]

After looking at the video in more detail, it seems to me that the siren must be rotating using its own rotator motor rather than being spun by hand - the movement seems too smooth to be done by hand.

If the CLM genuinely is rotating under its own power, it must be doing something like 16 RPM - or the video could have been speeded up a bit.

What do you think? Rotating under its own power? Or faked in some way?

Regards,
Jerry.

[ginbot86]

After looking at the video in more detail, it seems to me that the siren must be rotating using its own rotator motor rather than being spun by hand - the movement seems too smooth to be done by hand.

If the CLM genuinely is rotating under its own power, it must be doing something like 16 RPM - or the video could have been speeded up a bit.

What do you think? Rotating under its own power? Or faked in some way?

Regards,
Jerry.

CLM sirens have been out of service for decades; it's just simple stop motion animation that makes the CLM somewhat look like it's rotating.

In almost all CLMs' cases (or the ones that still stand) the transformer that converts the 3 phase power into an unusual 550 Volts was removed.

[Siren_Dude]

That video is the one I upload. I didn't film it but I know it must of been spun by hand. The building it was on was abandoned and wouldn't have any connection to power. The building was also in bad shape and is why the destroyed it. As you can see when it was falling, the rotation mechanisms were not locked in any way so the guy probably spun it around for some fun. I would think the CLM siren would have a much slower rotation, like many of the newer siren today.

[System 7000]

I hadn't considered stop motion animation - I thought that it was just a poor quality recording from an early cell phone camera.

So if this video of the CLM rotating is simply someone moving it by hand, what speed did CLM sirens rotate when they were in service?

There is a brief clip of a CLM in Alert here, taken from the Tocsin B recording. It sounds to me as if it is rotating quite quickly in this clip - perhaps as much as 6 or 8 RPM?

Regards,
Jerry.

[MattDean1003]

We're still not 100 percent sure whether it's a CLM or not.

[System 7000]

We're still not 100 percent sure whether it's a CLM or not.

I know that we can't be 100% sure, as there is no image of the siren being recorded. However, it does seem to have the same distinctive sound characteristics that the CLM siren had.

We certainly know that the CLM was a 10/12 port siren. I believe that the CLM had the 12 port chopper in the large horn on the front of siren, and the 10 port chopper in the smaller 'periscope' horn on the back of the siren. This would make the 12 port sound dominant, with the 10 port sound only coming through clearly when the siren was facing the person or microphone.

The recording from Tocsin B does seem to fit this description, so it seems probable that it is a CLM.

Regards,
Jerry.