ACA Screamer

**Company** | Alerting Communicators of America

 **Type of siren** | Omnidirectional Electromechanical

The **Screamer** was a series of small omnidirectional sirens that was produced by Alerting Communicators of America (ACA) and later the American Signal Corporation, and was the smallest of ACA's omnidirectional sirens (not including the short-lived Sentry 95), with the larger Banshee and Cyclone sirens being sold alongside them, and they enjoyed the longest production run of any of ACA's omnidirectional sirens.

## History and General Design

The Screamer first appeared in ACA's catalogue in 1968, a year after ACA was formed after B&N's closure. The Screamer is a very simple siren in design, with a motor of variable horsepower attached to a mounting bracket, that drives the rotor. Screamers come with a fibreglass weatherproof shroud that protects the siren from the elements, with the shape differing depending on the model. This simple construction makes them relatively maintenance-free. Early Screamers had a more unified design, with the same shroud shape being used for every model, lacking the mounting bracket on the motor, and the model names also differed from the later Screamers. This design change would occur in 1973 in an attempt to streamline the series.

The earliest Screamers were larger in size, utilizing an 8-port rotor and stator and a shorter motor that was 10HP. This would later be redesigned into the Banshee. These early 8-port Screamers are hard to find, as they were succeeded by the rest of the series. See the main image for an example.

The Screamer would be sold throughout the entirety of ACA's existence, all the way until 1994 when ACA faced bankruptcy and was reformed into ASC by Hörmann. Most of the Screamer line would be carried over into ASC and continue production, with the S-2, S-5, and S-7.5 all being produced by ASC. These are completely identical to their ACA versions, with the only difference being the paint being gray instead of yellow, and the addition of ASC decals. The Screamer S-10 was not carried over, as the need for dual tone sirens had passed, and as such production of the S-10 would end in 1994. These were sold as the SC-2, SC-5, and SC-7.5, and the Banshee and Cyclone would be sold as the SC-15 and SC-50, being incorporated into the Screamer series. Once ASC was bought back in 1998, the Screamers would be renamed to the OM-102, OM-109, and OM-112, with the Banshee becoming the OM-117. The Cyclone would be renamed to the C-125. The rest of the Screamers would be sold under ASC until 2004, when the series was finally retired in favor of ASC's newer Tempest series of sirens, the T-112 and T-121, which were both louder, and had DC motors allowing for battery backup.

Many Screamers still operate to this day as both their original and ASC variants, as their simple design makes them reliable, and low-maintenance. However, they never sold as well as Federal's Model series that they were competing with. But what the Screamers lacked in power, they sure made up for in punch. It can be expected that many Screamers will continue to warn the public for many years to come.

There are 6 different models of Screamer that were known to be produced:

## S-2

    These are the smallest of the Screamer sirens, as well as the cheapest. Originally introduced into ACA's lineup as the Screamer 102, it originally used the same shroud style as the other early Screamers. It would later be redesigned with a motor mounting bracket, a different shroud, and would be renamed to the S-2. The S-2 uses a 2HP AC motor, driving a 9-port single tone rotor which allows the siren to reach 102 dB at 100ft. These came in both single and three phase AC. A 2.5HP variant of this siren was also produced, tagged as the S-2.5.

These are intended for use at fire stations and other areas where small coverage is needed, similarly to Federal Signal's Model 2. Single-phase S-2s make use of a start capacitor, which creates the necessary phase shift in the start winding to get the motor rotating. The drag caused by the centrifugal switch that disconnects the start winding once the motor is up to speed causes a sharp and sudden drop in pitch during winddown, similar to Sentry Siren's single-phase sirens. The S-2 would continue to be sold after ACA's reformation into ASC as the ASC OM-102 until 2004.

## S-3

The Screamer S-3 was a very short-lived option, with no known units existing today. It's unknown when it was produced, but an advertisement for the Screamer series dated sometime after 1973 advertises this siren. It was rated for 103 dB at 100ft, and used a 3HP AC motor. It's likely the S-3 met a similar fate to Federal Signal's C1 1/2 Model 3, where it was only marginally better than the 2HP model while being more expensive to produce, and it was outshone in price/performance ratio by the S-5 and S-2. Little else is known about this model.

## S-5

These are the midrange option in the Screamer line, and can be differentiated from the S-2 and the S-7.5 by its shroud. Rather than having the chopper stick out from underneath the shroud, the shroud now completely covers the height of the chopper, which makes it visually distinct. This is due to the rotor and stator being shorter in height than other models. People often mistake the S-2 and S-7.5 for the S-5, due to not knowing the differences. The S-5 came exclusively in 9-port single tone, and the S-5 makes use of a 5HP AC motor, which increases its sound output to 105 dB at 100ft. These competed with Federal's Model series. These came in both single and three phase power. The S-5 would be later sold as the ASC OM-109 after ACA became ASC, and would be sold until 2004 when it was discontinued.

## S-7.5

These are essentially a higher horsepower version of the Screamer S-2, and can often be difficult to differentiate from a Screamer S-2 due to their near-identical design. What sets these apart from the S-2 is that they instead use a 7.5HP AC motor, giving it a snappier windup. They also have a larger lip underneath the stator, a shallower, wider skirt, and a larger capacitor housing on single-phase units. The S-7.5 was available exclusively in 9-port single tone, reaching 108 dB at 100ft. These are very often mistaken for Screamer S-2s and Screamer S-5s. These were available in both single and three-phase AC. These were also sold by ASC as the ASC OM-112 after ACA became ASC, until 2004 when it would be discontinued. The rotor from this siren would also be used in the PN-20 and later the RM-130.

## S-10

The largest of the Screamer sirens, these are very similar in design to the Screamer S-5 with the lower shroud, but rather than using the 9-port single tone rotor of the other Screamers, the S-10 came in 9/12 port dual tone, and 8-port single tone. Early units were also available in 10/12 port dual tone, using the rotor and stator from a B&N Mobil Directo. The S-10 uses a 10HP AC motor, and was originally released as the Screamer 100, before being redesigned and renamed to the S-10 in 1973. These are the only Screamers that came in dual tone, and it reached 112 dB at 100ft, the loudest of all Screamers. These came exclusively in three-phase AC, and unlike the rest of the Screamers, the S-10 was not carried over after ACA became ASC, and as such it was discontinued entirely in 1994.

## Screamer 105

    The Screamer 105 was a short-lived model of Screamer that was introduced alongside the others in 1968. The Screamer 105 is a unique siren, differing in design from the rest of the series. The Screamer 105 is a small omnidirectional siren with a motor-over-rotor configuration, with a 5HP Doerr AC motor driving a small 8-port single tone rotor and stator. The motor has a built-in two stage air compressor which works similarly to that of a Chrysler to feed air into the rotor, which is meant to improve the siren's performance. The siren's overall design resembles that of a CLM Type 92763CP, with a large mesh screen protecting the siren's motor and rotor. The siren was offered in both two or three signal models, with the three signal model having an extended intake with a coding damper to allow it to create pulse signals. At some point in the siren's lifetime, the siren was redesigned with a larger 9-port rotor and stator placed underneath the siren. which was similar to other single tone Screamers. The upper rotor was kept, and this was likely a last-ditch attempt to get more performance out of the siren as well as making the siren 8/9 port dual tone. The Screamer 105 was ultimately a failure, selling few units and being discontinued in 1973, when the Screamer line was finalized in design. Today, only a single example remains in existence, an early two-signal model on display at the Pacific Northwest Naval Air Museum in Oak Harbor, WA.