Tuba wrote:Is this the same with electronic sirens?
It's applicable to electronic sirens as well. Switching to electronic sirens you actually use less power in general since the tone generation is solid state instead of mechanical, and because of that electronic sirens aren't handicapped in the same way mechanical sirens are in terms of their ability to perform. You have a much easier time running big omnidirectional electronic sirens on battery power.
The biggest omnidirectional DC-powered mechanical siren on the market right now is the 16V1T-B, which is rated for a mile range and 129 dB. It's electronic siren counterpart would be the Whelen WPS-2910, rated for roughly the same spec. I've heard both, and they both perform about the same in the field. With that said, the 16V uses dual 8 HP 72VDC motors vs the 10 400 watt drivers and amps in the Whelen. It takes 6 batteries to run the 16V vs the 4 for the 2910. Once you go beyond that for omnidirectional mechanical sirens it becomes less practical. I have no doubt that the 40V1T will outrun a 2910, but now your're talking about a siren with a 40HP 208/240/480VAC motor. Not only are you stuck without the battery backup, now you're stuck with expensive 3 phase. Ultimately that is why Sentry never brought the 40V1T-B to production, at least officially anyway. It's not impossible for them to do it. Their 14 HP motor from the 14V-B can drive one of the siren's choppers, so they could very easily stick two of them together and make it work, but it would draw a hell of a lot of amps. That's what kept the siren from hitting the market to begin with. The rectifier, if the company they source theirs from even can supply one with the required output, would draw some serious amps on the line voltage side, and the batteries wouldn't take too kindly to it it either in a straight DC setup. If I had to guess they could develop a 96 VDC 14 HP motor to use in the siren. It wouldn't change the situation with the rectifier, but as a DC only siren it might take some of the heat off the batteries. Problem now is you have 8 batteries that are needed to run the siren. Even if the 2910 can't keep up in the field it now looks more practical and will cost less to maintain over the years, possibly less upfront as well, compared to the 40V1T-B.
The solid state property of electronic sirens also applies to rotating sirens. The ASC T-135 and a 560 Hz Whelen WPS-4008 will both hit 133 dB at 100 feet and get roughly 2 miles of range, but the Whelen can do it with 48VDC at 3200 watts vs the 72VDC 20 HP motor in the ASC. 4 batteries vs 6.