Product Data Sheet – TWM 220 N

AC Electromagnetic Yoke

The TWM 220 N electromagnetic yoke provides a portable means of creating AC magnetic fields for the detection of surface indications during magnetic particle testing.

The TWM 220 N can be directly connected to a 230V AC supply. Used with our adjustable pole pieces, it is ideally suited for testing uneven surfaces, tube bends, angle pieces, etc.

TWM 220 N Magnetic Yoke


  • Lightweight ergonomic design
  • Durable rugged construction
  • Oil and abrasion resistant
  • Individual serial number on each yoke

Specification Compliance

  • EN 60204-1: 2006
  • EN ISO 9934-3: 2002
  • DIN VDE 0100-410:2007
  • DIN VDE 0100-540:2012

Product Properties

Electrical supply 230 V
Frequency 50 Hz
Pole cross section 28 x 22 mm
Weight of yoke 3.2 Kg
Pull-off strength 18 Kg AC


Defect location: surface

Ideal for:

  • Field testing
  • Difficult to reach areas
  • Uneven surfaces
  • Spot inspections
  • In-service inspections
  • Weld inspection

Defect examples:

  • Seams
  • Tears
  • Shrink cracks
  • Grinding cracks
  • Quenching cracks
  • Fatigue cracks

Part Number



Dimensions A B C - Tiede Yokes

A: 168 mm
B: 268 mm
C: 158 mm

Dimensions D E F - Tiede Yokes

D*: 285 mm
E: 202 mm
F**: 250 mm

*Minumum pole distance

**Height in straight position

Dimensions G H J - Tiede Yokes

G*: 105 mm
H: 202 mm
J**: 250 mm

User Recommendations

NDT Method
Magnetic Particle Testing
Accessories Carry Case ( part numbers 136001, 136005)
Pole pieces See below
Download this Product Data Sheet as a PDF
Pole attachments for Tiede Yokes

Articulated legs for fillet seam inspection (part number 077004)

Pole attachments for Tiede Yokes

Articulated legs for inspection of angle pieces, tube bends and other uneven areas (part number 077001)

Pole attachments for Tiede Yokes

45° poles for fillet seam inspection (part number 077003)

Pole attachments for Tiede Yokes

Protective poles to safeguard the pole areas (part number 077002)