1. 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 lower third of the housing. This way air flows through the heating fins and therefore heats up faster.
For cooling devices, on the other hand, an installation in the upper part is recommended so that cold air can escape.
2. What has 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 an increase in the efficiency of the whole concept. In principle, attention particularly needs to be paid to the release of the heat output to the air.
Cooling devices are generally equipped with fans.
3. 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. Their surface temperature is therefore generally high. For this reason it is important to ensure a touch guard is in place and the distance from sensitive components and cables is big enough.
4. Which devices are suitable for big control cabinets?
To achieve better heat distribution it is recommended to install several heating devices, circulation fans or fan heating systems with separate temperature control.
5. Which temperature settings can be preset in Lm-therm heaters?
Tropical setting: <35°C: switch on/70°C: switch off
Highly tropical setting: <50°C: switch on/80°C: switch off
Frost protection: <10°C: switch on/60°C: switch off
However, attention needs to be paid to the heater’s intrinsic temperature if heaters with built-in thermostats and with a high performance level are used in tropical or cold regions!
6. When does the installation position achieve the maximum degree of efficiency?
Please take note of the specific device information in this regard. Generally, however, the natural convection mentioned in point 1 of the FAQ applies.
7. 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 the installation of a separate controller necessary. For PTC heaters it is generally recommended to insert a controller.
8. Are Lm-therm heaters electrically fused?
Heaters with a built-in thermostat are linear (ohmic). It is therefore possible to fuse them 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).
9. How are heating devices fastened?
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.