Thumper
Thumper turns up in 2 fields: electrotechnology, railroad. Here is what it means to the people in each one.
Thumper in electrotechnology
Field nickname for a surge generator that pulses a faulted cable so the fault can be heard and pinpointed.
A thumper is a capacitor-discharge surge generator that repeatedly dumps a high-voltage pulse, from a few kilovolts up to 32 kV or more, into a faulted underground cable. At the fault the insulation breaks down with an audible thump and ground vibration, which crews pinpoint with an acoustic pickup after a time-domain reflectometer gives an approximate distance. Too much thumping can damage healthy insulation, so energy and the number of shots are kept low.
"TDR puts the fault about 340 metres out, set the thumper to 12 kV and walk the route with the ground mic."
Thumper in railroad
A nickname for an older diesel-electric multiple unit train, known for its loud, rhythmic engine noise.
A colloquial term for early diesel-electric multiple unit passenger trains, named for the distinct, low-frequency rhythmic thumping sound produced by their four-cylinder diesel engines. These units were heavily used on non-electrified branch lines in the UK, but the term is occasionally applied by North American mechanics to any older, rough-idling diesel engine that shakes the carbody.
"They assigned us that old thumper for the branch line run, so bring your earplugs."