© THETA Ingenieurbüro GmbH 2018
Thermal Calculations
for Electrical Devices
For all those who operate electrical devices and installations, both the reliability and the price of the apparatus are important
quality features. The current-carrying capacity and the possible heating resulting from this quantity have a significant influence on
these features because the dimensioning of electrical devices depends on the keeping to temperature limits that are laid down by
law.
Consequently, the dimensioning of the heat dissipation is of great importance. This job should, therefore, be taken on by
specialists in measuring and calculating the heating of electrical devices. The usually combined and thus complex electrical-
thermal problems are diverse. This implies: a standard solution does not exist (see table).
We offer you an efficient engineer´s service in this field. Our strength lies in both the combination of several calculation methods
and the experimental verification of the results. By suggesting suitable materials and an optimum geometry for the devices to be
developed, we help you to minimise power losses and to improve the heat dissipation. In this way, we help you to construct
electrical devices showing a high current-carrying capacity.
With our service, we put you into the position to influence and optimise the qualities of your products in a well-directed way. Due
to our calculations, you save expenses for developements and tests.
Method
Thermal
Network
Method
Finite Element
Method
Advantages
Reliable information about convection,
coolant circulation and coolant rate
Calculation of parallel heat transmission
processes
Little calculation required
Precise calculation of heat conduction
Automatic drawing up of the thermal
network out of the geometry
Disadvantages
Complex heat
transmission processes
cannot be described
sufficiently
A lot of calculation
required, especially at
dynamic loads
Examples
Current-carrying capacity of
Kiosk Transformer Stations
Switchgears
Development of Fuses
Short-circuit calculations of insulated
busbars
Comparison of Thermal Network Method and Finite Element Method
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