Model L

Federal Signal Model L
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Company	Federal Signal Corporation
Produced	1946-present
Type	Directional Electromechanical
Sound output	112 dB @ 10 ft
Horsepower	½ hp
Voltage	120/240 V AC/DC
Preceded by	Federal Signal Model A Federal Signal Model D Federal Signal Model J Federal Electric Model 1/2
Documentation	Manual

The Model L is a small industrial electric siren produced by the Federal Signal Corporation, intended for use in industrial areas, indoor use, and short-range outdoor warnings. The Model L shares this purpose with the Model A in Federal Signal's lineup, being the larger and louder alternative. The Model L is the heavy-duty variant of the Model D.

Due to its small size, the Model L is popular both with industrial sites requiring a small siren, as well as with siren enthusiasts who commonly buy these sirens due to the ease of restoring and operating them. Model Ls can also be commonly found on drawbridges, warning when the bridge is raising. The Model L has stood the test of time as a reliable, cheap siren that gets the job done wherever it is installed. Its closest competitor is the Sentry F-2, as well as Federal's own Model A.

History and design

The Model L was introduced in 1946, making it one of the oldest sirens Federal Signal currently still produces. It was a modification of the existing Model D, which had been in production for a few years beforehand. The Model L is largely identical to the Model D but has a cylindrical intake instead of a conical one. The motor is also heavier duty than the Model D's motor and is suited for continuous extended use. The Model L is able to be mounted on nearly any surface and is cheap compared to larger sirens, leading to it becoming popular as an industrial warning siren, as well as a fire siren for rural communities.

The Model L is simple in design, being a small single rotor electric siren. The siren uses a small 8-port aluminum rotor and stator, driven by a heavy-duty ½ hp AC/DC universal motor running at either 120 or 240 V AC/DC depending on the model. 5-port models were also available as the Model A-5. The motor runs at a high rpm, with the siren peaking at a relatively high pitch. Due to the siren's small size, finger guards are included on the stator ports. The Model L is rated at 112 dB at 10 ft, with an operating range of 200 ft.

By default, the Model L comes with a metal stand which attaches to the rounded motor cover through two swivel mounts, which allows the siren to be aimed vertically wherever is required. These mounts are secured by nuts to keep them in place. The stand includes holes for mounting on a wall, floor or ceiling. The Model L has had almost no visual design changes over the years, with the only major change being the metal tag having been replaced by a sticker on newer units to save on costs.

The siren was originally very visually distinct from the Model A, using a cylindrical intake and flanged outer skirt to project the sound in one direction instead of the conical intake and skirt of the Model A. The Model A would later be redesigned in 1970 to use the same skirt as the Model L. The skirt was originally much wider than the later models, similar to the Model J's, with wide-skirt Model Ls being produced until the early Federal Sign & Signal era.

The Model L borrows the rotor and stator from the earlier vertical Model 1/2, which it would ultimately replace. The Model L shares its rotor and stator with its predecessor, the Model D, which was nearly identical except for using a conical intake instead of a cylindrical one. The Model L eventually replaced the Model D entirely. Like the Model A, the Model L comes painted red from the factory. Some vehicular sirens, such as the Model X and XL, use the same rotor and stator as the Model L as well.

Variants

Model LV

A vertical variant was produced for a period of time, named the Model LV. It is designed to be placed on top of traffic signals for street clearing purposes through the use of a small pipe and stand fixed to the inside of the Model L's intake instead of the normal stand, with the siren facing downwards. These are far less common to find than standard Model Ls, as the traffic lights these once stood upon have long since been replaced. The Model LV comes standard with screw threads attached to the top of the motor cover, which allows for an optional strobe beacon to be mounted on top of the siren. The Model LV is otherwise identical to a standard Model L. The Model LV is no longer in production.

Model PL

The Model L is one of several sirens that is compatible with the Pulsator accessory, and Model L units that were built with the Pulsator from the factory are designated as the Model PL. These are capable of making a rapid pulse signal by operating a flapper attached to the rotor through two wires and a gear reduction drive. These can be easily identified from other units by their distinctively shaped intake. These are uncommon to find, and no longer produced today.

Model K

A variant of the Model LV with a strobe beacon permanently attached to the motor cover also existed as the Model K, though this was later discontinued as the standard LV would have an optional removable beacon later in production. The Model K comes with a carrying handle, as well as a bell-shaped intake. The Model LV and Model K are no longer sold by Federal Signal. Both sirens are rare, with the Model K having very few known units left in existence and the LV being slightly more common.