Probes (3)

Question 1

Three basic types of coils

Answer 1

• Probe Coils (surface coils)
• Encircling Coils (outside diameter / O.D.)
• Bobbin Coils (Internal Diameter / I.D.)

Question 2

Probe Coil alternative names:

Answer 2

• rotary/spinning
• manual rotating
• pancake/spot
• pencil
• spring loaded

Question 3

Probe Coil features

Answer 3

• recessed
• protected by epoxy wear face
• non-conductive housing (plastic) to prevent heat transfer from fingers
• coil shielding to restrict spread of eddy currents

Question 4

Rotary or Spinning (Probe Coil)

Answer 4

auto scanning of bore and fastener hole side walls with the fasteners removed.

Question 5

Ring Probes (Probe Coil)

Answer 5

Central opening to scan around fasteners and holes on surface around the hole.
- donut shaped

Question 6

Manual Rotating Bore Probes (Probe Coil)

Answer 6

Use an adjustable collar to maintain position when in a bore hole and rotated by hand.

Question 7

Pancake or Spot Face Probes (Probe Coil)

Answer 7

Large diameter for large subsurface scanning

Question 8

Spring Loaded Probes

Answer 8

Used for scanning rough surfaces, minimizing lift-off

Question 9

Encircling Coils

Answer 9

Coils encircle around the outside of tubes, bars or rods, inspecting material outside -> inside
- material must be centred (use centring rollers)

Question 10

Bobbin Probes

Answer 10

Inspect inside tubes from the inside -> outside.

• attached to long flexible shafts
• must be centred within tube (plastic tangs, spring rollers, brushes)
• heat exchangers
• cooling tubes

Question 11

Why are Bobbin probes named what they are?

Answer 11

name “bobbin” from how coil is wound, similar to winding thread on a sewing bobbin