So today was the monthly siren test, and I was inside when I heard something that sounded like a single tone Thunderbolt. I went outside to see if I could hear it better, and I realized that it had the same sound as a 2001-130 only it was lower pitched. There was another 2001 nearby which was higher pitched and so the 2 sirens produced a perfect minor 3rd. It was very cold outside, so it could have been messing up one of the 2001's batteries, but the fact that the lower pitched siren was still very loud and was producing a minor 3rd with the higher pitched 2001 is what makes me suspicious. Since some new 2001s have been installed recently here, is it possible that FS has changed the 2001s to a 10 port configuration? All they would have to do is switch out the 12 port 2t22 rotor with a 10 port rotor, along with making a new stator, so is it possible that this could be the case?
It definitely wasn't an Equinox, it didn't have that nasally sound that they have.
I am most likely guessing it was just underpowered, but the fact that it had a normal and fast windup along with a normal rotation (at least thats what it sounded like), plus it didn't change pitch while it was running is just too suspicious for me to pass up. I will wait until next month, and if it sounds the same way then I will record it and post the recording here. I might also try to find it, and I suspect that this is a new installation because last month I remember no sound coming from the direction this came from.
Re: 10 port 2001-130s?
Posted: Thu Jan 05, 2017 4:44 am
by murrfarms
Zarlog wrote:It definitely wasn't an Equinox, it didn't have that nasally sound that they have.
I am most likely guessing it was just underpowered, but the fact that it had a normal and fast windup along with a normal rotation (at least thats what it sounded like), plus it didn't change pitch while it was running is just too suspicious for me to pass up. I will wait until next month, and if it sounds the same way then I will record it and post the recording here. I might also try to find it, and I suspect that this is a new installation because last month I remember no sound coming from the direction this came from.
If one of the batteries has a bad cell, the siren will run basically just how you describe. Most often the other three good batteries in the bank will supply enough starting current to allow the chopper motor to spin up at a normal rate of speed until the batteries plateau out in their capacity, and the chopper will then hold whatever top speed/pitch it reaches at a steady rate as long as the other batteries maintain their rated output current. However if the siren has a transformer rectifier (TR) to supply power and is using it for that particular run, I honestly can't think of what would cause that to happen right off the top of my head. Normally a DC electromechanical siren powered by a TR will either run at what is considered "normal" speed, or it flat out just won't run at all.
Re: 10 port 2001-130s?
Posted: Thu Jan 05, 2017 6:00 am
by DJ2226
Yep, sounds like what I experienced at one point with one Lee County, AL. The pitch right towards the end drops to about that same as a 10 port siren.
I experienced this during the January monthly test of the Eau Claire County WI system. The SRN closest to my house wound up quick, sustained steady pitch entire test, and seemed to rotate normal. But the pitch of the unit was noticeably lower than when I heard it for the June test. Maintenance is performed on all sirens each spring (around april), and I believe this siren has always done this around this time of year. It could be the near zero, to 5 below temperatures taking their toll on the batteries, but I am not sure. I told the city about it and they believe that batteries werent an issue. I am suspecting it was one of the batteries had gone bad as suggested above. The SRN's in the county don't have rectifiers, only the SRNBs, 130s and 508 does. I will eventually get around to posting the January test video on my YouTube page. DJ2226, your video sounds more like the batteries have all already gone bad, as the siren doesn't have a normal fast windup, and progressively gets worse throughout the video.