Ensuring that heat can be dissipated from electrical power loss via radiation or natural convection

A representation of temperature distribution in the Hirschmann RSR family.

The solutions for industrial requirements for data communication via Ethernet represent an important area of concern. The housing designs, in combination with the required electronic and electrical values, present a challenge for industrial Ethernet. For many solutions, Hirschmann Automation and Control forgoes active fans in favor of the long-life cycle of the products.

Nevertheless, it is necessary to ensure that heat can be dissipated from electrical power loss via radiation or natural convection. "Our managed IP67 switches from the Octopus Series are waterproof and therefore, have no ventilation slots," explains Paul Eberling, managing design engineer at Hirschmann Automation and Control. "Heat dissipation must be ensured by radiation and natural convection around the housing exclusively."

For products of the safety class IP 20/30/40, standards prescribe the possible widths of the ventilation slots. To assess the temperature conditions, Hirschmann engineers created several prototypes before the introduction of CFdesign in March 2006.

By simulating the temperature conditions in CFdesign, the usual six to 10 weeks required for prototypes and measurement data to determine a final housing design was cut to just one week.

In Solid Edge CAD, We Trust

Hirschmann relies on the Solid Edge CAD system for design. CFdesign is employed very early on at Hirschmann in product development and makes it possible to represent heat on the Solid Edge model directly.

A representation of flow vectors in the Hirschmann RSR family.

The initial design studies created in Solid Edge are transferred directly to CFdesign and evaluated. As a result, engineers obtain initial results about the thermal behavior of the system very quickly.

In addition to Upfront CFD, Paul Eberling also evaluated other CFD programs. "The price/performance ratio of CFdesign was the deciding factor for our decision," remembers Paul Eberling.

The fact that Hirschmann carries out fewer flow analyses than thermal analyses and that CFdesign should include enhancements for thermal applications in version 9 lead to the decision for CFdesign.

A 3-D CAD model of the new RSR family.

Hirschmann is currently developing a new housing design for the IP 20/30/40 safety class, and it was first introduced at the SPS/IPC/DRIVES 2007 conference and exposition in Nuremburg, Germany. It involves a modular housing system in which the width of the housing is variable among other things.

Using CFdesign, the engineers at Hirschmann were quickly able to determine the size of the housing and necessary heat sinks for the specified heat loss. The review of the results for the behavior when enlarging the housing by 30 mm with the same electronics on a prototype yielded a deviation of two to three percent to the results from CFdesign.

Above all, the Hirschmann engineers value the intuitive user interface of CFdesign with its checklist input options for material and loss parameters, even making it easy for employees who rarely use CFdesign to carry out analyses very quickly and safely. The automatic finite element networking rounds out the package.

As a specialist in automation and networking systems, Neckartenzlingen, Germany-based Hirschmann Automation and Control offers an integrated infrastructure for data communication throughout the company.

The fields of application extend from industrial connectors and media converters to industrial Ethernet and electronic control systems for construction machinery.