FAQs from Rohde & Schwarz

Switch cycles of the HMP Series


In the datasheet of the HMP series i could not find any information concerning the MTBF time of the relay switching the output power. Do you have any further information available?


The relay we are using has the following MTBF data:

Mechanical: DC coil: 20.000.000 operations min. (at 18.000 operations/hr)
Electrical: 100.000 operations min. (at 1.800 operations/hr under rated load)

As we do not switch the output of the HMP series under load in general, we can orient on the mechanical cycles.
Before we open the relay, we lower the output voltage using the linear regulator which leads to a better reaction time in comparison to only switching the relay.
Furthermore, the relay is first closed and then the voltage at the output is increased again by the linear regulator. This means that the load to be switched is very low.