|The Wayward Hammer
Joined: April 2006
Depends on the pump. Smaller ones have accelerometers (spelling - who knows?) mounted on the case that are usually integrated to give a velocity output. Inches per second being the most common.
The bigger pumps, like 5,000 HP, usually go with magnetic proximity probes that actually measure the shaft movement. Usually in thousandths of an inch.
Any reading above the alarm limit is routed through the electronic controls for the circuit breaker, or a mechanical relay, and that throws the breaker.
Probably could a decent reading on quake magnitude from these if I could get the historical data...
I know, more than you ever wanted to know. Earthquakes can be fun from about 2000 miles away.