Helios SB-250-EC SilentBox Acoustic Inline Fan

■ Installation:
Installation in any position without restriction – horizontally, vertically or pitched – suitable for intake or extract (Exception: SVS must not be installed with the swing-out motor impeller unit facing upward).

■ Motor
Totally enclosed external rotor motor with ball bearings, impregnated windings insulation class F, designed for continuous operation, maintenance free and interference-free.

■ Casing
Like an internal attenuator. Acoustically lined with abrasive resistant 50 mm thick mineral fibreboard. Four quick release clamps permit easy access to motor scroll and impeller set.
Swing out motor and impeller.
Spigots on intake and exhaust twin-seal rubber gaskets fit standard ducts. All parts manufactured from galvanised sheetsteel.

■ Impeller
With backward curved highquality polymer blades. Inflow via inlet cone.

■ Electrical connection
Terminal box (IP 54) is supplied with a 60 cm long electric cable.

■ Motor protection
With thermal contacts wired in series with the windings. To reset the thermal contacts the main supply must be switched off and on.

■ Speed control
Stepless 0 – 100 % using electronic controller or 5 step transformer controller (see table).

■ Protection class
IP 44

■ Casing
Extremely flat casing in longer design with more than 50 mm thick sound-absorbing mineral wool lining and glass fibre surface. The acoustic box which is placed in front of the fan reduces the sound level for the intake significantly. The sound pressure level is reduced to a smaller extent (see sound levels in the tables above the performance curves).

■ The swing out motor and impeller unit permits maintenance and cleaning without disassembly of system components. The swing-out range must be considered for the inspection flap.

■ Impeller
Energy-saving centrifugal impeller with backward curved blades from high quality polymer. Dynamically balanced for low noise operation.

■ Electrical connection
Terminal box (IP 54) mounted on running cable.

■ Motor protection
With thermal contacts wired in series with the windings which automatically reset after cooling.

■ Speed control
Stepless 0 – 100 % by use of electronic controller or 5 step transformer controller (see table).

■ Protection class
When installed in ducting the fan is rated IP 44.