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Flashcards in Eddy current Deck (43)
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1

which component in an eddy current inspection system provides current to the test coil?

oscillator

2

which component converts changes in eddy current magnitude and distribution into signals to be processed?

bridge circuit

3

what effect does high conductivity have on eddy current depth of penetration?

reduced depth of penetration

4

what's the term for signal changes caused by the eddy current field intercepting a corner of a part?

edge effect

5

if all other factors remain unchanged what effect does higher frequency have on eddy current depth of penetrations?

shallower depth of penetration

6

what's the definition of the standard depth of penetration of eddy currents?

point where eddy current strength drops to 36.8% of surface strength

7

how many times deeper than the standard depth of penetration is the effective depth of penetration?

3 times

8

what's the desirable signal-to-noise ratio for flaw detection?

3 to 1

9

how can you eliminate line voltage fluctuations that may be affecting your signal-to-noise ratio?

switch to a battery powered unit

10

based on application, what are the three general classifications of eddy current probes?

1. surface 2. Inside diameter (ID) 3. Encircling

11

what characteristics of a probe determine the surface area inspected?

diameter of the probe and any shielding in the probe

12

what type of eddy current probes concentrate the field directly under the coil and overcome many of the problems associated with edge effect?

shielded probes

13

what's the definition of impedance?

total opposition to the flow of AC in an eddy current coil

14

Where do phase angles form?

where the sine waves, representing 2 elements of AC, cross

15

What does the line (formed on a CRT) between the dot with the probe off the part (Po) and the dot when the probe is placed on the part (P1) represent?

lift off

16

how can you configure impedance plane instruments to measure amplitude changes only?

calibrate the unit in the sweep display mode

17

how much operating time remains when the low-battery indicator indications appears?

1/2 hour

18

Which control on the Nortec 2000 is used to adjust numerical parameters or the display appearance, depending on the function selected?

smartknob

19

What key is pressed on the Nortec 2000 to display information to adjust the basic operating conditions of the unit, such as frequency or gain?

MAIN/FILTER key

20

Which function key will activate the bolt hole scanner controls?

SETUP/SPECIAL key

21

Which of the two immediate executions keys is used to execute an instrument operation or respond to a prompt?

ENTER key

22

Which menu soft key would you press after the MAIN key in order to change horizontal and vertical gain together?

press gain menu soft key after you've pressed the MAIN key

23

What is the operating frequency range of the Nortec 2000?

100 Hz to 12Mhz

24

what two ways can the phase angle or rotation be set?

using the smartknob or INC/DEC keys

25

Which two keys must be pressed before you can adjust the sweep with the smartknob?

first the DISP key then the DISPLAY key

26

From which menu would you start to reset the unit to factory default settings?

SETUP menu

27

Where should the flying dot be located after nulling is complete?

50 percent full screen height and 50% full screen width

28

What must you make sure of when placing the probe on the crack standard?

make sure probe is on a good area away from any cracks

29

When is the sensitivity check required?

when using the Air Force General Purpose reference standard

30

during surface flaw detection, how would you estimate a discontinuity's size?

by comparing it's indication with your crack standard's indication