Eddy-current system for the vibration-testing of blades

Patent · Sat Jan 01 00:00:00 EST 1977

OSTI ID:862838

Jacobs, Martin E ^[1]

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1. Chillicothe, OH

This invention is an improved system for the vibration-testing of cantilevered non-ferrous articles by inducing eddy currents therein. The principal advantage of the system is that relatively little heat is generated in the article being vibrated. Thus, a more accurate measurement of the fatigue characteristics of the article is obtained. Furthermore, the generation of relatively little heat in the blade permits tests to be conducted in low-pressure atmospheres simulating certain actual processes environments. Heat-generation in the vibrated article is minimized by utilizing eddy currents which are generated by an electromagnet whose magnetic field varies but does not change polarity. The typical winding for the electromagnet is excited with pulsating d.c. That is, the winding is alternately charged by connecting it across a d.c. power supply and then discharged by connecting it across a circuit for receiving current generated in the winding by self-induction. Preferably, the discharge circuit is designed so that the waveform of the discharging current approximates that of the charging current.

• DOE Contract Number: E(33-2)-1
• Assignee: United States of America as represented by United States Energy (Washington, DC)
• Patent Number(s): US 4026142
• OSTI ID: 862838
• Country of Publication: United States
• Language: English

Related Subjects

eddy-current
vibration-testing
blades
improved
cantilevered
non-ferrous
articles
inducing
eddy
currents
therein
principal
advantage
relatively
heat
generated
article
vibrated
accurate
measurement
fatigue
characteristics
obtained
furthermore
generation
blade
permits
tests
conducted
low-pressure
atmospheres
simulating
processes
environments
heat-generation
minimized
utilizing
electromagnet
magnetic
field
varies
change
polarity
typical
winding
excited
pulsating
alternately
charged
connecting
power
supply
discharged
circuit
receiving
current
self-induction
preferably
discharge
designed
waveform
discharging
approximates
charging
eddy current
magnetic field
power supply
eddy currents
accurate measurement
pressure atmosphere
charging current
charge circuit
inducing eddy
accurate measure
currents therein
/73/