Federal Signal Model 2

The **Model 2** is a small 2-horsepower siren that has been produced by Federal Signal and its predecessors since 1929 and is the cheapest purpose-built outdoor warning siren on Federal's current lineup, as well as one of the longest-produced sirens in the world. Over the 90+ years the siren has been produced; it has gained a reputation as the fire siren of choice for many fire stations across the world.

The Model 2 is still in production to this day, over 90 years after its introduction. Due to its small size, great performance for its size and power requirements, ease of maintenance, and low cost, the Model 2 is easily the most common siren in the United States and Canada, where it finds use as a fire siren for many fire departments. It can also commonly be found in chemical, oil, and industrial plants, where they serve as an emergency siren or lunch whistle. It competes today with other small electric sirens such as the Sentry 3V8, Federal's own Model ECLISPE8, and the ASC T-112, among other sirens.

## Design

The Model 2 is a small, simple vertical siren, using a 2 hp universal motor to drive a small, 5-port single-tone chopper at 6,000-8500 rpm, which allows the siren to reach roughly 102 dB at 100 ft. The Model 2 is available in two power configurations, the 120 V Model 2-120, or the 240 V Model 2-240. Model 2 sirens are AC/DC because of the universal motor, able to run on either 1 ph AC or high voltage DC. The siren is not available in 3 ph models. The rotor on the Model 2 is open on both the top and bottom, which allows the siren to intake on either side of the rotor to maximize airflow through the chopper. This is also what allowed the siren to be later repurposed as the Thunderbolt 1000, as air can pass through the motor, unlike sirens with single-sided rotors. The housing itself is compact and efficient, projecting both the sound from the rotor, as well as the intake evenly in all directions with little wasted output. Due to the use of a universal motor, the Model 2 has a logarithmic windup, and a rapid winddown.

The Model 2 is designed for use at fire stations and other areas where long-range coverage isn't needed, such as coverage gaps in a larger system, as well as for industrial use where a smaller industrial siren such as the Model A or Model L won't cut it. The Model 2, along with the rest of the Model series (then known as the Fedelcode series) was intended to replace the antiquated Type Mach. B, which was lacking in performance and being outsold by its competitors such as the Sterling Model M. The Model 2 matches the Type Mach. B in performance, while being much smaller, less expensive to produce, easier to install and maintain, and far more weatherproof. The two sirens were produced at the same time for a short time before the Type B was discontinued in the 1930s.

## History and Changes

    The siren was originally introduced by Federal Electric in 1929 as the Federal Electric/Fedelcode Type Mach. 2, with the earliest Type Mach. 2 units using a housing that looked similar to later Fedelcode sirens. This was then switched to a 3-louvered design, with 2 louvres on top, and 1 on the bottom. These sirens were much taller than modern Model 2s, using a "long-legged' design with taller mounting legs. These units lacked an intake cone, so they weren't as effective as later models. Their motors also had 4 brushes instead of the 2 that are used today. The Fedelcode Type Mach. 2 could optionally come with a coding mechanism allowing it to make a pulse signal, and these units were dubbed the "No. 2 Fedelcode Code Siren".
Coded signals were achieved using a rotating coding ring on the stator, instead of a damper. This ring was gear-driven by a separate smaller motor, and this would rotate a second stator to block the stator ports, nearly silencing the siren instantly. When the motor was de-energized, the second stator would move back out of the way, allowing the siren to instantly return to full output. Due to the fast-acting mechanism, the coding on this siren was fast enough that it was claimed to be capable of creating Morse code signals, something that damper-equipped sirens are unable to do. Federal Electric units were identical to the Fedelcode units, except for lacking the coding option and having the "FEDERAL" badge instead of "FEDELCODE" on the housing.

In 1948, when Federal Electric became Federal Enterprises, the Fedelcode Type Mach. 2 was slightly redesigned with a small rounded nub on top of the housing but was otherwise identical to a Fedelcode Type Mach. 2. The coding mechanism would also be discontinued, and the Fedelcode name was dropped in favor of the Federal Enterprises name, and the "FEDELCODE" and "FEDERAL" badges were discontinued. The siren would also be renamed to the Model 2. The siren would then see another redesign sometime in the early 1950s, when the siren would switch to a new design with much shorter legs and evenly spaced louvers, and an intake cone was added to improve the siren's performance. The siren became overall much more compact as a result. Both of these designs were short-lived, being produced for only a few years each, which makes these the least common Model 2 designs.

The design was changed again to the modern current design when Federal Enterprises became Federal Sign & Signal in 1955, featuring a new shroud with 1 louver on top, and 2 on the bottom. This version of the Model 2 continues to be sold to this day and has remained largely unchanged since then, besides the tag placement. The Model 2's chopper and motor were used in Federal's popular Thunderbolt series that were produced between 1952 and 1990, with the Thunderbolt 1000 essentially being a rotational supercharged Model 2. Early Thunderbolt 1000Ts made use of the 2T's 4/5-port rotor, though the Thunderbolt 1000T would eventually use its unique 5/6-port rotor. The Model 2 was rebranded and resold by several other manufacturers such as GCS and W.S. Darley & Co, and these are identical to a standard Model 2 except with their custom housings.

### Model 2T(T)

A dual-tone variant of the standard Model 2 was introduced in the late 1940s/early 1950s as a dual-tone alternative to the standard Model 2, named the **Model 2T** (or **Type 2TT** for units built during the FS&S era, while Enterprises units are simply marked as Type 2). The siren was intended for civil defense purposes during the Cold War. The Model 2T used a 4/5 port dual tone chopper and stator instead of the 5-port the normal 2 used, though this resulted in the siren only being able to produce 100 dB at 100ft due to noise cancellation from the sounds clashing, as well as the shorter height of each port. The Model 2T shares the same rotor as the 4/5-port variant of the Thunderbolt 1000T built between 1954 and 1959. The Model 2T was otherwise entirely identical to a standard Model 2 and came in both the "long-legged" and standard variants.

    The Model 2T was discontinued sometime around 1981 for unknown reasons, leaving the standard single-tone Model 2 as the only available version. Due to its shorter production run, Model 2Ts are much harder to find than standard 2s. Model 2Ts were often painted civil defense yellow, which can help identify suspected 2Ts although this is not foolproof.

### Canadian Model 2/Model 2-3Z

Federal Signal also had a variant of the Model 2 that was designed specifically for the Canadian market and is essentially a Model 2 flipped upside down. This variant is marked on the tag as "**Model 2-3Z**", although Federal also refers to them as "**Canadian Model 2**" in the manual. The motor is now located on top of the rotor, with the intake being located between the mounting legs. Model 2-3Zs lack an intake cone due to a lack of space between the mounting legs. The motor itself is surrounded by a cylindrical cover, which shields it from the elements. On earlier models, the cover was attached to the siren itself and was separate from the housing, but this was changed on later models to integrate the motor cover with the housing itself, likely to reduce the cost of production. These changes were meant to protect the siren from the harsh cold and snow of Canadian winters and improve the siren's durability.

The rotor, motor, and stator are all identical to a standard Model 2. A common misconception is that these sirens run at a lower pitch than standard Model 2s, however, this is not the case. This is usually due to the brushes wearing out, or the siren being underpowered as many of these are 240 V models running on 120 V. The siren's housing physically resembles Fedelcode era Model 2s with the skirt placement, although they are significantly shorter in height with the bottom piece being much shorter. Many also have the nub on the top of the housing shared with early standard Federal Enterprises units.

Model 2-3Zs are by far the most common fire sirens in Canada, though lack of maintenance has led to many units dying or wearing out as the brushes age. It can be assumed that these began production around the same time as Fedelcode era Model 2s, although these appear to have been produced as late as 1986 with minimal design changes. Little documentation exists from Federal Signal about these sirens beyond the manual. Interestingly, the manual depicts the siren with a standard Model 2 housing despite all Model 2-3Zs using their housing. The Model 2-3Z is no longer in production today, having been replaced by the standard Model 2.