Sterling Vertical Siren

Sterling Vertical Siren series
Company	Sterling Siren Fire Alarm Co. Sentry Siren, Inc. (Model 2V8 only)
Produced	1931?-???
Type	Omnidirectional Electromechanical
Sound output	-
Horsepower	2-7.5 hp

The "Sterling Vertical Siren" is a series of vertically-oriented electric sirens that was produced by the Sterling Siren Fire Alarm Company of Rochester, New York. These sirens were marketed for general alarm use, and were most commonly sold to fire departments to serve as an outdoor fire alarm, calling firemen to a fire station. The series of sirens was believed to have been introduced between 1931 and 1937.

The vertical lineup consisted of three main models, each a different size to specifically fit the needs of different customers. These were designated as the Model 2V8, Model 3V and Model 5VX (also available as the 3VX or 7.5VX).

History and design

The development of vertical Sterling Siren Fire Alarms is believed to have begun in mid-late 1930 or early 1931. The mastermind behind the project was Merton C. Armstrong, Plant Superintendent and the primary designer and engineer of the company. The sirens were likely intended to serve as Sterling's competitor to the "FEDELCODE" series of sirens, which had been introduced just a few years prior, seeing widespread success and installations along the East Coast, which Sterling Siren had previously dominated.

While the specifics of the design for the sirens varies between the three primary models, all three of them share a general pattern and various design features. Each of the three models consists of a cast iron base on which a vertically oriented electric motor is mounted. Atop the motor sits an open-topped, cast iron fan housing, in which the cast aluminum fan is mounted. The siren's head assembly is capped off with a stylized spun aluminum dome that both shields it from the weather, and helps guide sound from the siren's ports downwards, making these sirens especially suited for rooftop installations.

The electric motors on the sirens were shielded by a sheet-steel hood that wraps around the edges of the mounting base and fan housing. The siren's Identification badge is typically mounted to the motor hood, allowing for key information on the machine to be identified without requiring disassembly. On Models 3V and 5VX, the motor hood has numerous scale-like louvers punched into it, allowing the siren to intake air more effectively. These are not present on the Model 2V8, as it intakes air from large openings or an air intake tube above the impeller, rather than through the bottom of the assembly. Due to having a taller stator, the Model 2V8 features an additional aluminum cowling under the top rain cap, helping it project sound downwards.

Models

Model 2V8

The Model 2V8 is the smallest of the 3 models within the vertical lineup. Mod. 2V8s were intended to compete directly with the FEDELCODE Type Mach. 2 siren. Similarly to a Type Mach. 2, the Mod. 2V8 utilizes a two horsepower electric motor to drive a 5 port, 8 inch rotor at around 7000 RPM. The Model 2V8 was also available in 4/5 port dual tone as the Model 2T (or possibly 2T8, it is currently unclear). Model 2V8s had AC/DC universal motors furnished in both 110 and 220 Volts AC. The sirens were small and with low power requirements, making them rather popular amongst smaller fire departments. Early production Mod. 2V8s feature a ported mounting stand, much like what is seen on Models 3V and 5VX. These were dropped fairly early in production for unknown reasons.

Model 3V

The Model 3V served as a sort of middle ground option between the Model 2V8 and Model 5VX. The Model 3V is believed to utilize a 220 Volt, 3 Horsepower motor, running at around 3300RPM. Currently, all documented Model 3Vs seem to be single phase, with examples being found with both 8 and 12 ported impellers. Not much is known about Model 3Vs due to their rarity.

Model 5VX

The Model 5VX is the largest siren in the vertical lineup, featuring an impeller with comparable diameter to that of a Model M siren. These sirens were advertised as filling a very similar role to the Model M, essentially serving as its vertical counterpart, with similar range, volume and power requirements being claimed in advertisement material.

The Model 5VX, much like the Model M, was offered in 3, 5 and 7.5 horsepower configurations, with 3 and 7.5 hp sirens being referred to as Models 3VX and 7.5VX respectively. The Model 5VX was offered in 8, 12 and 16 port configurations, with 12 port models having a noticeably larger rotor when compared to 8 and 16 port models. Typically, Model 5VX sirens operate on 220 volts AC, and were known to be furnished with both single and three phase electric motors to suit the needs of Sterling's customers. It is likely that two-phase models were also offered, but none are currently known to exist.

The Model 5VX enjoyed a very similar level of success to the Model 2V8, especially along the Eastern Coast of the United States, but both of the two models were greatly outsold by the Model M in terms of sales.

Trivia

• Most vertical Sterling sirens feature a tag with an identical layout to that of a Model M's tag, but with different fonts for the lettering. Models manufactured before February 1936 feature a "Patent Applied For" lettering along the bottom.
• Model 2V8s were manufactured by Sentry Siren, Inc. for a short period after Sterling Siren's closure in 1973. These are distinguishable from genuine Sterling Model 2V8s by their vented motor hoods. These are typically furnished with 4/5 port rotors, which were rarely used on Sterling models.
• The patents for the Model 5VX depict it with a solenoid-actuated damper for use as a coding siren. It is not known if these sirens were ever produced.
• Models 3V and 5VX were often referred to as Models "K2" and "K5" by siren enthusiasts. These names have since been proven to be misnomers, and were never stamped onto Sterling Vertical Sirens. This misnomer is likely due to a widespread image of a Model 5VX's tag, where the VX was mistaken for a K due to the angle and lighting of the image.
• With roof mounting losing popularity in the 1950s and noise pollution becoming more of a problem, it is not uncommon to find Vertical Sterling sirens with their cowls removed or horns added in an attempt to increase the siren's effective range.

Further Reading

• Patents for a Sterling Vertical Siren
• Map of Sterling Siren Fire Alarm locations