predominantly. Here too, these days press-fit and spring contacts are taking over to
some extent. These give the advantage of a simplified assembly and thus savings in
production of the module user. For the power terminals in the medium and high power
range screw contacts (chapter
are still the standard in connection techniques. A
replacement with other methods is not envisaged here. In the high power range screw
connections are also the standard for the control terminals, as here greatest emphasis
is put on reliability andmechanical resilience.
Independently of the selection of the connection method, the application directives of
the manufacturer with regard to the assembly of the electrical terminals have to be
observed. Generally these will specify the maximum load and possibly restrictions
regarding the exertion of forces on the terminals. For screw connections they further
define theminimumandmaximum torque forces.
The electrical terminals of a module are not designed to bear high mechanical
forces but instead, to provide a reliable electrical connection. The torque and/or torsion
forces mentioned in the manufacturer’s datasheet have to be strictly adhered to. The
module terminalsmust not bemisused as a central mechanical mounting point for PCB,
cables and bus bars for example. Instead, these are to be stabilised mechanically by
additional measures. Otherwise they are jeopardised to fail very soon through
mechanical effects such as continuous vibrationor shock loads.
Example of a 62mm module which had been exposed to excessive torsion
10.2.2Heatsinkassemblyand thermal grease
Power semiconductors need sufficient cooling in order to be fully utilised. Without it,
current capabilities of several 100A to 1000A could not be realised. The cooling of the
semiconductors with their modules or cases which house them is achieved by adding a
cooler acting as aheatsink.