E57
| E57 | |
| |
| Produced | 1957/1959-1992 |
|---|---|
| Type | Omnidirectional Electromechanical |
| Frequency | 50/60 Hz |
| Horsepower | 5.3-6.7 hp (4-5 kW) |
| Voltage | 220/380 V 3 ph |
The Standard Siren 1957 (German: Einheitssirene 1957, abbreviated E57 or E 57) is a simple medium-range omnidirectional siren. It superseded the earlier Air Protection Siren 1952 (German: Luftschutzsirene 1952, abbreviated L52) and Air Protection Siren 1941 (German: Luftschutzsirene 1941, abbreviated L141) as the German "standard siren", and was produced from its introduction in 1957 until its eventual discontinuation in 1992. The E57 is, without a doubt, one of the most well-known German sirens, and it has maintained this status even more than 30 years later after its discontinuation. Thanks to its basic yet rugged design, it was widely installed throughout Germany and exported to various other nations. The E57 also served other purposes both during and after its production run, often used as an alarm to alert the fire brigade. The E57 spawned a countless number of imitators, such as the East German VEM DS977 and the Greek VILMA Motors NEVA/VILMA 55, and its design's influence can be found throughout Europe.
History and Design
In the mid-1950s, the West German government, in collaboration with Elektror, Siemens, Helin, and Roland Sirenenbau, began to draft a brand-new standard siren which would offer superior performance and longevity compared to the sirens produced at the time. This came about after the recent division of Germany and fear of an imminent attack brought about by the Eastern Bloc. This development was primarily headed by Elektror who had earlier created the L141/L52, which the new siren would ultimately supersede. This project ultimately resulted in the creation of the E57, which conformed with the German Institute for Standardization (German: Deutsches Institut für Normung, abbreviated DIN)'s standardization order for the design of air raid sirens (DIN 41096). This standardization came about in 1952, and resulted in the creation of the L52 to meet its new requirements. The E57 was designed as a relatively maintenance free siren with a simple design; the drafting of the E57 was primarily focused on prioritizing a longer life span rather than sound output.
The E57 consists of a 9-port rotor and stator, with a grille carried over from the L52 protecting debris from entering the siren. The rotor on the E57 had thicker walls than that of the L52s, slightly improving the siren's range. A flange below the stator directs the siren's sound downwards and outwards, and has a rotation arrow cast on, which displayed the correct way the rotor was supposed to spin. This arrow was also present on the L52 but was instead cast on to the motor. The E57 is powered by a 220/380 V 5 kW (6.7 hp) asynchronous 3 ph electric motor underneath the stator driving the rotor at around 2800 rpm, brought up to this speed around 2-4 seconds after activation. The color of the stator and the motor is RAL 7026 (granite grey), as standardized by DIN 41096. The siren's rotor is coated in a varying color of polyamide paint, as an exact one was not specified in the DIN's standardization. The motor shaft's countersink is rounded on the E57, whereas the L52's was square. The E57 lacks protective conductor connections of any kind, unlike its predecessor; this was likely a casualty of making the siren as simple as possible to produce and install.
Like the L52, the E57 was designed with inexpensiveness and mass-producibility in mind. It achieved this through several means; Its most notable feature, the large protective roof shielding the siren from the elements, is constructed out of fiberglass reinforced plastic instead of steel, contributing to a less costly siren. This also makes the siren lighter overall and prevents the roof from warping and being dented, as can be seen on many L141/L52 units. Additionally, the E57's mounting holes for the roof, located above the stator ports, sit level with the stator, as opposed to the ones of the L52 which were recessed into it. The holes drilled into the stator used for attaching the grille in place on the L141 are not present on the E57, simplifying its production further. A triangular base borrowed from the siren's predecessor, with 3 holes in each corned, allows the E57 to be bolted to a flat surface. Conforming to DIN 41097, which standardized mounting methods for air raid sirens, tripod and simple pole roof mount designs were available to purchase with the E57, and it could also be fixed to a tall steel pole. The flanges on the sides of the motor that connect it to the base of the siren were made straight on the E57, compared to the L52 where they were curved.
After being finalized in 1957 the E57 was officially put into production in 1959, with the 1st units going up sometime later that year. Despite seeming relatively identical, the E57 had a varying number of manufacturing differences depending on which company produced the exact unit, and some manufacturers were inconsistent with the way the siren was designed, making it extremely difficult to differentiate what manufacturer made what unit. The E57 was never 100% standardized down to the last detail; only its approximate dimensions and configurations were specified in DIN 41096, and the fact that multiple manufacturers independent of each other produced them separately would make it very hard for each and every unit to be identical. Some E57 units even have differing rotor diameters, meaning that not all E57 rotors are interchangeable. While Elektror and Roland casted their parts themselves, Siemens and Helin often outsourced production of their sirens' rotors and stators to Garthe, a casting company based in Ennepetal. Elektror also used Garthe's parts for a brief period, though transitioned away from them in the mid 1960s. There are a few subtle differences; some of Helin's E57s had roof mounts which weren't recessed into the stator, unlike most of the other manufacturers.
A few Siemens-Schuckert produced sirens had a shorter rim above the stator, with longer ports. Siemens E57s also had 4.7 kW (6.3 hp) motors, resulting in a lower pitch and slower windup compared to other units (the less-powerful motor had no effect on the siren's overall volume). Regardless of uniformity problems, the E57 was an immediate success following its introduction, and the amount of units installed rose exponentially throughout the 60s and 70s. Luz-Sirene's Type L (German: Typ L), a similar siren inspired by the DIN design, was also produced around this time, though failed to see a comparable level of success as the E57. 1975 was an interesting year for the E57; during that year, the E57's design was improved upon to account for a minor design flaw; a washer with a sealing ring was installed on the motor shaft, below the nuts that hold the stator in place to prevent water from accumulating around the space in between the rotor and the shaft, with would ultimately result in the motor being flooded; this was a fate that many pre-1975 units shared after their protective roofs had been blown away or uninstalled for whatever reason. Furthermore, in 1975, a company named ABEG became involved with the production of the E57; ABEG primarily refurbished and reinstalled older E57 units from the original manufacturers, and even built their own units.
E57s that have been restored by ABEG can be easily identified by the ABEG tag on the motor, although without a view of the tag, they become significantly harder to identify; ABEG often used spare parts they had in storage from all of the other manufacturers' E57s. As a result, ABEG-restored E57s often have inconsistent designs and can be mistaken as products of the other manufacturers, or appear exactly identical for that matter. HÖRMANN Warnsysteme, a giant in the German siren industry, likely took over ABEG's refurbishment operations in the 1980s (with apparent exact dates of 1982, 1983, and 1986 being thrown around, although none of these are confirmed).
WIP In 1979, HÖRMANN acquired the Santa Cruz, CA-based Raytek Technologies, and began to sell both the electronic ECL and electromechanical E57 as part of an effort to expand their influence across the globe, and their sights were set on the United States. These E57s (named the E57USA) were partially modified for the American market but still retained largely the same design.
The E57 was formally discontinued in 1992 after the end of the Cold War. After Germany's civil defense division was abolished, the ownership of these sirens turned to the municipalities of which they were installed in. Many E57s saw new lives primarily as fire sirens. HÖRMANN continued to supply refurbished E57 units until late 2012, when the siren was removed from their website after an overhaul and effectively replaced by the ECN and ECI.
References