Technology

Precise technology behind the Lm-therm products

Quality through craftsmanship

The precise technology of Lm-therm products ensures high quality and efficiency. You can find all the necessary information and interesting key facts on the technology behind the Lm-therm products here:

  • Why is heating/cooling necessary?
  • Information on climatisation / FAQ
  • Calculation tool

If you have any other questions, our team of professionals will be happy to provide you with information at any time. Just contact us!

Why is heating and cooling necessary?

Lm-therm’s heating and cooling devices ensure the right climate in the control cabinet and thus increase the reliability of control systems and ensure that they function properly. Fans and cooling devices prevent individual components or entire control systems from overheating, for example.

Information on climatisation (FAQ)

Here you can find important information and answers to frequently asked questions on the climatisation of control cabinets and the basics regarding thermal processes and special product-specific features.

What is the ideal place for installation in the control cabinet?

Natural convection is the best way to achieve optimum heat distribution. It is therefore recommended to install the heater in the bottom third of the housing. This way, air flows through the heating fins and therefore heats up faster.

With cooling devices, on the other hand, installation in the upper section is recommended so that cold air can escape.

What needs to be considered with regard to convection?

The goal is not to affect the natural convection of the heater negatively by packing the installed devices extremely densely. Installing heaters with fans or blowers or using circulation fans can lead to forced convection. This gives the heating system a higher degree of efficiency and therefore achieves better heat distribution. This results in the whole concept becoming more efficient. Particular attention needs to be paid to the release of the heat output to the air as a matter of principle.

Cooling devices are generally equipped with fans.

What do you need to know about the surface temperatures on PTC heaters?

Due to the lower surface temperature, Lm-therm heaters with built-in thermostats are a safe alternative to PTC heaters. PTC heaters do not have a temperature-triggered shut-off function and their surface temperature is therefore generally high. That’s why it’s important to ensure that a touch guard is in place and that there is enough distance from sensitive components and cables.

Which devices are suitable for big control cabinets?

To achieve better heat distribution it is recommended to install several heating devices, circulation fans or blower fan heating systems with separate temperature controls.

What temperature settings can be preset in Lm-therm heaters?
  • Tropical setting: <35 °C: switch on/70 °C: switch off
  • High tropical setting: <50 °C: switch on/80 °C: switch off
  • Frost protection: <10 °C: switch on/60 °C: switch off

However, if heaters with built-in thermostats and high outputs are used in tropical or cold regions, attention needs to be paid to the heater’s intrinsic temperature!

When does the installation position achieve the maximum degree of efficiency?

Please take note of the information for the specific device in this regard. Generally, however, the natural convection mentioned in point 1 of the FAQ applies.

Is it necessary to install separate controllers?

Heaters with built-in thermostats do not require separate controllers. However, factors like the size of the control cabinet, the number of built-in devices, and other external influences may make it necessary to install a separate controller. For PTC heaters it is generally recommended to insert a controller.

Are Lm-therm heaters electrically fused?

Heaters with a built-in thermostat are linear (ohmic). They can therefore be fused equal to the load current (I=P/U). PTC heaters, on the other hand, are to be protected by a slow-blow fuse with five times the load current (I=P/Ux5) because of the high inrush current (PTC effect).

How are heating devices mounted?

Heating devices can be snapped onto a 35 mm DIN rail or screwed in directly (take note of the device specifications). The electrical connection can be implemented via a connection line or a connection terminal on the device.