The Siren Board

Well about a month ago while taking pictures in Frankfort, KY, I came across this:















I stood there, scratching my head, bewildered.

I called the EMA director this morning before recording today's test in Frankfort (Trocks797 on YouTube). While I forgot to ask specifically about the batteries, he did say Frankfort has no plans to remove or replace the Thunderbolts. He did say not to record the one at Bondurant Middle School, which is the one pictured here, because the rotator is broken right now and they are fixing it this month.

While he should be able to provide me with a definite answer when I speak to him next, what do you guys think is going on here??

By the way, all connections to and from the battery are in place. It appears as if it is active and doing something. What gives?

I would guess the battery box is for the federal control box. probably powers the radio receiver box. probably a two way radio too.

There's absolutely no way those batteries have enough juice to run a 10 hp [3 phase] blower!

My best guess is that they run the chopper and rotator in an emergency under the philosophy of something is better than nothing.

Yeah, I knew that was impossible. Ian and a few others told me that. Ian also said the memory on the board is non-volatile, as in it doesn't need power. I should note this is the only one in the system that has the battery pack. Maybe they bought it hoping it would work!

The chopper by itself is not really going to provide any adequate sound, let alone during an emergency. Maybe the controls were donated off a newer setup where the siren itself was somehow damaged beyond repair with the controls intact?

What confuses me is that, why would you run the controls on battery, and the siren on non-battery? If there doing that.. It would be awesome to see a ThunderBolt fully working that ran on batteries though!

Guys, it's pretty apparent NOTHING on that siren except for the controls is powered by those batteries. Powering that siren would require a very large inverter, which is not present in those pictures.

I'm thinking somebody got suckered on upgrading that siren for the narrow band requirements.

I wouldn't be too quick to discount the possibility of battery backup.

The 10 HP 3 phase motor data plate shows 35A @ 240V which works out to 14,500 Watts (V x I x 1.73). I didn't see data for the chopper or controls, but they probably consume another 2000-3000 Watts, for a total of about 17,500.

The lower box (which contains the batteries) appears large enough to hold at least 6 automotive batteries. Assuming 250 Amp-hours per battery, that works out to 18,000 Watt-hours at 12 VDC. Of course, the batteries won't be able to supply that power indefinitely, but they would most likely last long enough for a typical warning.

The last few years have seen big advances in high power semiconductors, which has led to very efficient, compact DC to AC inverters. A 15 kW 3 phase DC-AC inverter that measures about 35x26x16 inches can be found here: http://www.solren.com/pvi10-15kw.html

If something similar to that is in the upper box, I wouldn't be surprised if this T-Bolt has been retrofitted with full battery backup.

holler wrote:Guys, it's pretty apparent NOTHING on that siren except for the controls is powered by those batteries. Powering that siren would require a very large inverter, which is not present in those pictures.

I'm thinking somebody got suckered on upgrading that siren for the narrow band requirements.

I might be wrong here, but isn't the chopper motor (shared by the model 2) capable of running on DC? Or is that just the newer Model 2s only?

Landmobile: First the input says 205-385 volts which means you would need 18 batteries to power the inverter.

Second the battery box holds 4 batteries look at the rivets in the cabinet. That is where the shelf is for the top two batteries.

I would think a tbolt could be battery back up with a new motor for the blower and a rotate motor. Not real sure about the chopper at 48 volts it would be slow. But this installation looks interesting and I would like to know more.