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fire_freak_57
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2001-130 Strange “Grinding” Noise During Pitch Fluctuations

Thu Apr 18, 2019 12:16 pm

My local 2001-130 (our Village’s only siren) was installed in March 2017, and I have noticed rather abnormal pitch fluctuations with it since installation.

I am working on expanding our siren system by refurbing and donating/helping install 4 ACA Allertor 125’s that came from a system in Columbiana County that recently upgraded, but anyways, this unit in particular has some issues with it.

I am in contact with a village council member that is running for Mayor next year and I need to let him know if this siren needs fixing so it can be fixed as this opens a public safety issue (nevermind the fact that we only activate the sirens if a tornado is actually on the ground but not for tornado warnings in which rotation is observed or radar indicated, I am working with them to change this policy as well because it is another safety issue in itself) but this siren has had some abnormal pitch fluctuations since installation. Knowing this is typical with 2001-130’s, I did not question it initially.

However, over the past year (2018) these fluctuations have become more abnormal and noticeable from quite a distance and the siren has started to make a strange “grinding” noise, which is incredibly concerning for such a new siren in itself. This grinding noise, as well as the pitch fluctuations in itself, have become progressively worse over the past year. The siren did not do this when it was first installed, so I think there is some kind of mechanical problem that needs fixed. This siren is the closest to my home, so I hear it go off every Saturday at noon and have noticed this issue over the past year. For background, we do not test the sirens during winter. They are only tested from April through October and remain powered on during the winter but testing does not happen during that time.

Our other 2001-130 at the local high school about 3 miles from this unit was installed in March 2009 and does not do this, (but has a low mounted antenna so half the time it does not activate, working on a fix for this as well) so this means this is not normal by any means.

Any ideas of what can be causing this and what maintenance needs to be performed? The vendor for both installations was Federal Field Services out of Wauseon, OH (our regional FS dealer).

I need to let the Village know ASAP because if the siren failed to sound during an actual emergency due to this problem it could become a liability.

Here’s some video examples of what I’m talking about. I have included videos from 2017 shortly after it was installed so you can compare that to videos from 2018 and 2019 where you can hear the strange grinding noise:

Video from August 2017 (grinding noise absent):


https://www.youtube.com/watch?v=4sFziRWk9lc

Recording from 2018 (grinding noise noticeable):


https://www.youtube.com/watch?v=1Mv7eC0ESTI

Up-close recording from last week (my friend recorded this):


https://www.youtube.com/watch?v=CxEXzfYY3nE

My distance recording from last week (grinding noise noticeable):


https://www.youtube.com/watch?v=9wksk0s_0oY

Any feedback on this and possible corrective measures are appreciated as I plan on contacting them about the same time I present to the Village my plan on refurbishing and installing 4 ACA Allertor 125’s to fill in numerous coverage gaps (it would cost about half of what a new 2001-130 install would cost and they’d be getting four sirens instead of one new one...) about this as well as I plan on helping FFS with the Allertor installs to get them installed according to ACA specs.

Anyways, about this siren, any feedback is much appreciated as this could potentially become a serious safety issue if left undiagnosed and could become a liability should an emergency arise and the siren does not work. It is especially concerning because this siren is only two years old, and our other 2001-130 which is now 10 years old does not have any issues like this. Thanks!
Last edited by fire_freak_57 on Thu Apr 18, 2019 8:52 pm, edited 1 time in total.
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Owner of a Allertor 125 Control Cabinet, EOWS Driver, and other odds and ends.
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DJ2226
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Re: 2001-130 Strange “Grinding” Noise During Pitch Fluctuations

Thu Apr 18, 2019 8:00 pm

The pitch fluctuations are caused by wind. All 2001's will do it with enough wind actually. I came across a video a few years ago of a SRN doing it during a tornado warning. It takes a bit of wind for the older models to do it, which is why you don't see it too often.... most places don't test in the middle of a storm. It's most noticeable on the Equinox and 130 and happens with less wind. It has something to do with the design of the intake. The main change they made coming from the SRNB was making the back of the siren longer to remove the support bar that used to cross over the intake for the chopper. I'm not too sure exactly why it makes them fluctuate in pitch, but if I had to guess the chopper probably goes under a bit of positive or negative pressure when the wind is blowing towards the face of the siren since it's located higher up into the box. The pitch issue isn't really something that has concerned Federal Signal enough to worry about over the years. The 130 has been out for close to 15 years and the Equinox for about 8, and nothing, maybe besides the bushing in the rotator, has changed throughout the production of the series. That said unless the motor or rotator brushes are about to let the smoke and sparks out the head probably is fine. Try and listen to it when the weather is clear with very calm winds. It probably won't fluctuate like this.

I think the grinding sound is the siren housing resonating with vibrations from a combination of the motor and rotor and the overall sound being produced. It's been more audible on the 130 and Equinox, but other 2001's have been heard doing it too. I heard it in person with a SRNB before. I think it being louder with the 130 and Equinox also has to do with the longer back, as it would give more area for the sound to resonate out of. Certain pitches might react differently with it as well, so if the voltage going to the head changes from one test to the next and is slightly higher/lower, which can happen with variations of load on the grid that effect the output of the rectifier or chargers, it might change with it. It could also be the air going up into the intake. That's what contributes to the undertones heard with sirens like the P-50 and Eclipse NH/8.
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coastalsyrolover
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Re: 2001-130 Strange “Grinding” Noise During Pitch Fluctuations

Fri Apr 19, 2019 12:39 am

The equinox fluctuates REALLY bad. Like in every video I’ve seen.
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