Constructions Électriques du Nord
Northern Electrical Constructions (French: Constructions Électriques du Nord; abbreviated CEN), was a manufacturer of electrical machinery such as motors, generators, and outdoor warning sirens founded in 1897. CEN was one of the earliest manufacturers of sirens in France, producing them at least since 1926, and even after the company's closure, their sirens are a common sight in France.
History
Constructions Électriques du Nord was founded at the turn of the 19th century in 1897, with 1 source suggesting they were founded even earlier in 1885[1]. CEN started as little more than a small electrical machine shop, producing small motors which would power formerly steam-driven wool mills. The company's operations grew in size and scope during the 1900s, and the outbreak of World War I likely saw an increase in CEN's manufacturing capabilities.
Contrary to what some believe, CEN did not produce air raid sirens during World War I, with the only known manufacturers of sirens at the time being CICCA and Chollet, of which very little are known about. CEN's sirens came at a much later date in 1926, when the company began to produce various models of outdoor warning sirens under François Odoux's direction, the CEO of the company at the time. CEN produced sirens from then until its closure, with units hailing from the 1980s to support this claim. Production of CEN's sirens during the 1940s likely continued to increase during World War II, with high demand for sirens to warn the public of Axis air raids.
After the war, Odoux saw an opportunity to improve the primitive state of individual controls for small machines, with many at the time still controlled by pulley devices and belt transmissions. He founded FOX Motors in 1949, which complemented CEN's manufacturing and focused on fractional horsepower motors. FOX Motors began to produce sirens of their own in 1964, named the MONICA and PAKITA. The latter became predominant in the market, and competed with CEN's own NP2S and NP3S, despite Odoux's intention with FOX Motors to not compete with CEN at all. CEN began to produce brand new brushless AC motors begun in the early 1970s, as well as waterproof motors specifically built for a "UNITEC"'s water pumps, who later licensed their design to the American firm WEMCO.
Unfortunately, CEN had closed up shop by 1986, and became KM Europ, who carried over CEN's designs and model naming scheme. KM Europ as an independent company now no longer exists; it was later acquired by Finescur in 2006, who still produces CEN's sirens under the KMsecur name, and was split with Moflash in 2018, although Moflash's portion of KM Europ does not produce outdoor warning sirens. Though little is known about CEN, they were one of the most influential siren manufacturers in France during the 20th century; despite the company being long gone, CEN sirens are one of, if not the most common sirens in France's nationwide siren system. Today, FOX Motors continues CEN's legacy with their still manufactured PAKITA series of sirens, derived from CEN's models.
Products
Type NP2S and NP3S (collectively refered to as "NPxS")
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The Type NP2S consists of an 8-port rotor and stator. 8 conical horns are attached to each stator port, which likely improves the sirens' audible range. Whether there 10-port units are genuine Type NP2Ss or another product of CEN entirely is unclear. A few units only have 6 horns, despite the siren having 8 ports. Some units have horns with mesh screens installed to prevent debris from entering, while others do not; whether this is because they never came with them, or the mesh screens have fallen off or degraded is unknown. The horns are offset with the angle of the ports, which is typical for most French sirens produced post-WWII.
The Type NP2S was also available without horns, leaving only the horn connecting pieces attached to the stator and mesh screens covering the openings. A good number of units, assuming they are Type NP2Ss, feature a rotor-over-motor configuration, having a large conical shroud of varying size and shape suspended above the stator shielding the siren from the elements. The Type NP2S is driven by a 50/60 Hz 2.2 kW (3 hp) 3 ph 230/400 V motor above the stator, which spins the rotor at around 2850 rpm. It is unknown if 1 ph units were ever offered. The motors utilized on the Type NP2S are taller and fan cooled ("Totally enclosed, fan-cooled" type), unlike the Type NP3S's which is shorter and lacks a fan; this is currently the only way to differentiate the two models apart, aside from looking at the tags bolted to the motor.
A cylindrical assembly with a mesh screen wrapped around it serves as the siren's intake and base. This design was later carried over to KM Europ after CEN went defunct, who seemingly only branded the siren and made no other changes. CEN and KM Europ-era units are relatively identical, and the same can be said for units produced once KM Europ became KMsécur. Despite the difference between the 2 sirens being relatively minimal, the Type NP2S was not nearly as successful as the Type NP3S; comparatively less Type NP2S units exist compared to Type NP3S.
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An older version called the Type NP3S also exists, it is otherwise identical to the NP2S albeit it has a different motor that is shorter and lacks a cooling fan. Sound-wise, the NP3S has a very strong bass-y undertone with a faint raspiness, versus the NP2S' characteristic 50Hz rasp (when correctly wired). It also has been used as the base for the "Mark 2" gearbox sirens. It is not known if the NP3S and NP2S share the same rotor vane design (smooth, conical rotor on the NP3S) or not. Regardless, as far as those two models are concerned, they seem to be 99.99% identical. It is rumored that some NP3S units were fitted with a coding brake., although this is not confirmed.
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The Type NP3S was also available without horns, leaving only the horn connecting pieces attached to the stator and mesh screens covering the openings. The Type NP3S is driven by a 50/60 Hz motor above the stator (with exact details unknown), which spins the rotor at around 2850 rpm. No known single-phase unit exists. The motors fitted on the NP3S is shorter and lack a fan, unlike the Type NP2S which is taller and fan cooled; this is currently the only way to differentiate these sirens, aside from looking at the tags bolted to the siren, curiously enough, on the NP2S the tag is on the motor itself, but on the NP3S it is on the stator baffle.
Just like the NP2S, this design was later carried over to KM Europ after CEN went defunct, who seemingly only rebranded the siren and made no other changes. CEN and KM Europ-era units are relatively identical, and the same can be said for units produced once KM Europ became KMséscur. Despite the difference between the 2 sirens being relatively minimal, the Type NP3S was the more successful of the two, with a majority of CEN sirens being Type NP3Ss. The KMsécur/KM Europ units all have a TEFC[2] motor regardless of being a KM2S or KM3S.
According to a document[3] found on KMsecur's website, the number in the KMxS-series represents the distance the sound of the siren will travel, (e.g 2km without horns and 2.5km with horns for the KM02S, 3km without horns and 3.5km with horns for the KM03S), it is possible that the same logic also applies to the NPxS-series.
"Mark 1" Gearbox sirens
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CEN produced several other models of sirens, none of which have known model names. These all share similar designs, with several unique aspects and variants. An example of these would be their "Gearbox" (the name is conjectural, as their exact model number is still unknown, they were often erroneously called double motor[5]/double speed sirens both nicknames coined by enthusiasts), which came standard in 8-port or 10-port, with conical horns are attached to each stator port. Some units have horns with mesh screens installed to prevent debris from entering, while others do not; whether this is because they never came with them, or the mesh screens have fallen off or degraded is unknown. The horns are offset with the angle of the ports, which is typical for most French sirens produced post-WWII.
These sirens came standard with a gearbox to speed the motors up. As expected, the rotors of these spin quite fast, at around 4400 (for the finned motor Mk.1 units) and 3750 (for the smooth motor ones) rpm. This is about twice as fast as most standard French sirens, thus the "double motor"/double speed" name. Both are relatively identical, with the only differences being variations in the motors used. At least 1 of these sirens was also equipped with some sort of damper mechanism. With a few exceptions, most of these sirens had their motors below the stator as opposed to on top of it like the Type NP sirens, with units with their motors on the bottom having a large conical shroud of varying size and shape suspended above the stator shielding the siren from the elements. It is unknown when exactly these were produced, and few of them exist, although they seem to be very common in Alsace and Oise.
There are two major variations known, the older "motor on bottom" ones are dubbed "Mark 1" or "Mk.1" and can be divided into multiple sub-categories:
- Mark 1 "Smooth motor" (10 ports), these are by far most common and the oldest of all Mark 1 units, they could optionally be fitted with a coding "sleeve" (though this was a rare option: only one was confirmed to have been equipped with it, another siren is suspected to be coded, but it has not yet been confirmed) they have a rather smooth sound owing to them spinning at around 3750 RPM.
- Mark 1 "Finned motor" (10 and 8 ports), those are relatively late models, came in both 10 and 8 ports configurations. The 10 ports units spin at approximately 4400 RPM and have a higher pitched sound. It is suspected that those might be the so-called "Moteurs Fox MONICA" sirens, although this is unlikely to be the case.
- Mark 1 "Finned motor 8-port", those could either come with the older finned-type motor as found on their 10-port counterparts or a short gearbox and different motor (as found on the "Mark 2" 8 port models), the short gearbox units are by far the rarest, and also the last Mark 1 units that CEN produced before switching to the "Mark 2" type.
"Mark 2" Gearbox sirens
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Those sirens are the successor to the older "Mark 1" Gearbox sirens, they came in the following configurations:
- 8 ports, those are identical to the NP3S, but with a short gearbox added between the rotor and motor, those seem to be relatively common as far as Mk.2 units are concerned. Mk2 8-port units all seem to have a characteristic "clunking" noise when spinning up.
- 10 ports, those use a NP3S/NP2S-style rotor/stator assembly but with 10 ports instead of 8, there are a few sub-variants known to exist, with the most common version being equipped with tall gearbox as used on the later "finned motor 10-port" Mark 1 units and a TEFC[2] motor as found on the NP2S.
- "Deep tone" 8-port, this extremely rare version (only ~5 are known to exist in France, with 3 having been installed near Toulouse and one known active in Cernay, Alsace, the last one sits in an unknown location) instead of a gearbox, they are equipped with a gear reducer (which is considerably shorter in height than the gearboxes) and a larger TEFC[2] motor, as a side effect, they are considerably quieter than other models while having a very fast, near-instantaneous wind up. This model by far seems to either have been quickly discontinued or was only built on custom order.
References
- ↑ http://pgosse.chez.com/CEN.htm (in French)
- ↑ 2.0 2.1 2.2 Totally Enclosed, Fan-cooled
- ↑ https://www.kmsecur.com/wp-content/uploads/2018/11/Texte-KMxS.pdf
- ↑ https://www.moissac.fr/actualites/cadre-de-vie/sirenes-dalerte-mardi-14-fevrier/
- ↑ This name is slightly misleading; these sirens do not have 2 motors, but instead utilize the pre-existing motor as well as a gearbox.