Hibbert Magnetic flux standard. THis consists of a high quality stable ALNICO magnet with a circular magnetic field gap. A circular coil can be triggered to drop through a given height through the magnetic field gap. This generates an known (calibrated) magnetic flux. The unit is marked with 22200 Lines. This is an old magnetic unit.
I line = 1 Maxwell = 1-8 Wb. Therefore 22200 lines = 0.000222 Wb = 222 mWb.
The standard has two different coils. one 10 turns with origonal wiring and one with 100 turns that has been repaired and rewired.
When used on a magnetic flux meter as seen in pictures measured with 10 turn coil 2.15 mWb.
With 100 turn coil 21.2 mWb.
The unit comes in the origonal box.