Customised subrack extension for CPU ventilation
In order to ensure a very high level of reliability, no rotating components are normally permitted in railway technology, so that possible causes of damage are minimised. A HEITEC customer had planned the use of a higher-performance CPU for one of its existing systems in the railway sector In order to ensure a very high level of reliability, no rotating components are normally permitted in railway technology, so that possible causes of damage are minimised. A HEITEC customer had planned the use of a higher-performance CPU for one of its existing systems in the railway sector. This significantly more powerful CPU had to be cooled due to the high heat development. This required the use of fans that were not provided for in the previous system.
Brief technical description
- Customised, stainless steel housing (V2A)
- 4 axial fans 12V
- L x W x H: 240 mm x 84 HP x 1 U
- Temperature switch-off for temperatures < -20°C
- Shock and vibration resistant in accordance with EN 50155
- Extended temperature range in accordance with EN 50155
DC wide range voltage input 14.4V - 154V
Realisation
As a solution, HEITEC designed a cost-effective, 1U-high sheet metal housing that can be used as an extension to the existing system. This meant that the customer was able to continue using his existing subrack in full. The housing provides space for four axial fans, which cool the CPU sufficiently. There are a number of requirements that the system must fulfil for railway technology applications. One of these is high shock and vibration resistance of the system. But the system must also function perfectly and fail-safe in the extended temperature range from -40°C to +85°C. The mechanical stability was achieved through a design customised to the application. HEITEC was able to fulfil the ambient temperature requirements by selecting the appropriate components and painting the assemblies.
However, good maintainability of this subrack extension for easy handling during operation was also a prerequisite. HEITEC realised this with an innovative design. The fan housing consists of just three parts, which are screwed together. In addition, the filter mat used can be changed easily and without tools.
In this particular application, it was also necessary to develop a circuit that included an integrated temperature switch. This ensures that the fans are no longer supplied with power at a temperature of less than -20°C and prevents damage to the fans caused by the cold.
Customer benefits
- Customised system
- High impact and vibration resistance
- Extended temperature resistance from -40°C to +85°C
- High reliability and service life
- Good maintainability thanks to the use of only a few parts and a filter mat that can be replaced without tools
- Cost-optimised design
- Railway certified according to EN50155
