Frank Szmulowicz, Ph. D. (asker) Jun 19, 2015:

Vielen Dank. I like the answer "smoothing choke". It fits the context perfectly. Would Lancashireman care to enter it so I may acknowledge his (I assume) contribution?
Johanna, congratulations on successfully juggling four children and four chickens, without dropping one in the process.
Thank you Erik for your extensive discussion. You convinced me as to Lancashire's proposed answer.
In general, I am very impressed by the level and tone of the German-English proz and your kind hospitality here.
Johanna, congratulations on juggling four children and four chickens without dropping one in the process.

Erik Freitag Jun 19, 2015:

Drossel "dr." steht hier für "Drossel" (engl.: choke), da hat Lancashireman auf jeden Fall recht.

Die Bezeichnung "Impulssperrdrossel" ist ein bisschen kryptisch. Ich nehme an, gemeint ist einfach eine Glättungsdrossel.

Frank Szmulowicz, Ph. D. (asker) Jun 19, 2015:

I am most grateful for all the help to you Johanna and to Lancashireman. I am sure we are closer to the answer than before.

Johanna Timm, PhD Jun 19, 2015:

dr. kann in dem Kontext eigentlich nur Dreh*(er/ung) sein (sage ich mal als deutscher Muttersprachler) - but electronics is not my field, so I can't help you with a translation !

Lancashireman Jun 19, 2015:

Sperrdreher? Only three references found, all in patents.

Frank Szmulowicz, Ph. D. (asker) Jun 19, 2015:

Thank you. And what is the best English translation in relation to inverters?

Johanna Timm, PhD Jun 19, 2015:

Sperrdreher lmpuls-Sperrdreher (durch Drehen bewirkte Sperrung)

Lancashireman Jun 19, 2015:

Sperrdrossel? Not sure how best to translate. Some sources suggest 'reactance coil'.