500 Series
| 500 Series | |
 | |
| Company | Federal Signal Corporation |
|---|---|
| Produced | 1953-1982? |
| Type | Electromechanical |
| Sound output | 123-130? dBc at 100 feet |
| Horsepower | 10-20 |
| Voltage | 120, 220, 240, or 480V |
| Succeeded by | RSH-10 |
The 500 Series was a line of electromechanical sirens produced by Federal Sign & Signal. It went through a lot of prototyping, ranging from a coded unit that allows it to make a "pulsed" signal, along with variants of single and dual tone models, even different phase motors were tested. They finally settled on one design that was compact, yet effective. This model unfortunately was advertised as a "mid-range" siren by Federal, which in turn caused their Thunderbolt siren to outsell it by a long shot. The most powerful unit they made was the 10/12 port, 3-phase 500SHTT, meaning single head two tone.
Earlier Models
The earlier 500, mostly seen around Los Angeles, have a shorter projector unlike the later ones, they were offered in 9/12 port, 12 port, and more rarer 8 port. Some models had support bars inside the projector to mitigate warping.
500-DHTT
The 500-DHTT is a dual horn variant of the 500, they have 2 rotors and stators on each side, one 8 port, the other 12 port. They were offered with a 15 or 20 horsepower motor. They use the same short projector as the earlier 500, and were produced as late as 1965-67. Roughly 100 were ever made, and 7 units are known to exist as of 2020.
