دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: a special coupling between the camshaft and the magneto of a large engine. At cranking speeds the magneto is made to rotate in quick spurts to produce large pulses of voltage at the time of ignition for each cylinder.

n: an alternator with permanent magnets, which is used for generating current for the ignition system of an internalcombustion engine.

n: an instrument used to measure the intensity and direction of a magnetic field, especially that of the earth.

n: a surveying device that measures the intensity and direction of the earths magnetic field.

instrument used to measure the intensity and variances of the magnetic fields in the earth.

n: (mmf) a force that carries a magnetic pole of a given strength around a magnetic circuit.

n: magnetostriction vibration mainly caused by change of magnetic field, thus it causes change of magnetic material. The vibration that caused by alternating current through sympathetical steel magnet core, which force to bit, the speed higher than the trad

n: a tightly banded scroll of special steel that vibrates when a magnetic field is applied to it. The vibration of the scroll sets off a transmitter, which is alternately switched on and off at 15 to 60 times per second. The transmitter causes compressional sound waves to travel through the formations surrounding the borehole. Each formation material will exhibit its own characteristic effect on the elastic wave propagation.