Heaters

A control cabinet heater protects electronic and electromechanical components from damage caused by cold, moisture, and condensation, thereby contributing to the system’s functional and operational reliability.

Extreme temperatures and condensing humidity can lead to corrosion, short circuits, leakage currents, malfunctions, and a significantly shortened service life of the components.

Thermal management encompasses all measures for heating, cooling, and dehumidification to maintain the permissible operating temperature and humidity in the control cabinet and prevent failures in the long term.

As component density increases—for example, as part of Industry 4.0—heat dissipation rises significantly; even a temperature 10 K above the permissible operating temperature can cut the service life of electronic components in half.

The required heating capacity depends on the control cabinet size, the power dissipation of the installed devices, the desired internal temperature, and environmental influences; for larger cabinets, multiple heating units with separate controls are often used.

Lm-therm uses both classic heating resistors as well as PTC heating elements and PTC cartridges.

For good heat distribution, the heater should be mounted in the lower third of the enclosure so that the air can rise through natural convection and heat the entire cabinet.

Depending on the device type, mounting is done either by snapping onto a DIN rail or by direct screw fastening; electrical connections are made via a connection cable or terminal block.

Natural convection must not be impeded by excessive equipment density; recirculation fans or forced-air heaters can be used to achieve forced convection with better heat distribution.

In large control cabinets, it is often advisable to use multiple heaters or forced-air heaters with separate temperature control to avoid hot spots and ensure uniform temperature distribution.

Heaters with an integrated thermostat typically do not require a separate controller; however, the size of the control cabinet, component density, and environmental conditions may make the use of additional controllers advisable. For PTC heaters, an upstream controller is generally recommended.

In addition to the standard setting range of <25°C On / 60°C Off, typical presets include, for example, a tropical version that turns on below 35°C and off at 70°C, a high-tropical version with 50/80°C, and frost protection with 10/60°C.

For demanding environments, devices with a high protection rating—e.g., IP65 for certain control cabinet heaters—are available to effectively keep out dust and moisture.

Heaters protect against low temperatures and condensation, while cooling units dissipate waste heat; together, they ensure that the internal temperature remains within the permissible range and that components operate reliably.

Most units are designed for quick installation on a DIN rail or with screw fasteners; connection is typically made via terminals or pre-assembled connection cables.

Lm-therm provides a calculation tool for heating and cooling capacities and offers technical consulting to review the calculated design and propose a suitable solution.