The GRB Galaxy Roof Mounting Belt Driven Twin fan range represents the latest development from Vent-Axia in high performance, run and standby twin fan. Designed to be controlled inconjunction with Vent-Axia Trakmaster twin fan controller range, the total package offers the end user flexibility when interfaced with or without a (BMS) Building Management Systems, such as: manual selection; 12/24hr auto changeover ensuring the extended life of the fan and motor; night setback during low levels of occupancy, for energy management control during 24hr extraction.

The unit casing is manufactured from mill finished aluminium fitted with discharge aluminium weather louvre with bird mesh as standard. Assembly is controlled to BS EN ISO 9001.

Individual gravity return shutters are fitted as standard to prevent air recirculation through the standby fan or the system during shut down periods. Galaxy Roof Mounting Fans are only suitable for horizontal mounting. When installed on a shallow pitch roof a special upstand will needed to compensate for the angular difference – to be manufactured by others.

To meet COSHH requirements, double pole service isolator switches are fitted and pre-wired from the fans and mounted to the outer casing to reduce installation time and cost. Access to the fan section is via an easily removed top access panel for cleaning and maintenance during shut down periods.

The Galaxy range is available in four models with extract performance ranging from 0.02m³/s up to 2.5m³/s (720m³/h to 9000m³/h), with pressure characteristics of up 400Pa.All models
are supplied with inlet spigots on the underside of the unit casing and a discharge anodized aluminium weather louvre.

Fan / Motor Assembly

Galaxy GRB belt driven fans are double inlet double width, forward curved centrifugal fans belt driven by totally enclosed fan ventilated motors, wound to suit 220-240V/1/50HZ or 380-415V/1/50Hz electrical supply. Protected to IP54, against dust and water jets complying with BS EN 60529.

Motor insulation is Class F as a minimum, suitable for operating temperatures up to +40°C. The fans and motors are mounted on a steel frame, with anti-vibration mounts between the frame and casing and a flexible connection between the fan scroll and fan plate, minimising vibration. All belt driven Galaxy units are supplied with metric pulleys to ISO 4183 and wedge belts to ISO 4184 and DIN 7753.

Electrical

All Motors are available in either, single phase 220-240V 50 Hz capacitor start and run. Three phase 380V-415V 50Hz. The service isolator is supplied with all models with 20mm and PG11 entry, protected against dust and water jets from any angle.

Performance
The GRB fan performances is tested in accordance with test BS848 Part 1.

Sound Levels
The fan sound levels are measured in a reverberant chamber in accordance with BS848 Part 2. Published dB(A) figures are free field sound pressure levels at 3m with spherical propagation at a reference level of 2 x 10–5Pa (20 micro-Pascal). The inlet and outlet sound power level spectra figures are dB with a reference of 10–sup>12Watts (1 pico-watt). To ensure minimum noise levels during speed control, an auto transformer speed control is recommended.

Quality Assurance
Design and manufacture are in accordance with the standard for quality management system BS EN ISO 9001.