Ewing's hysteresis tester

Ewing's hysteresis tester

[¦yü·iŋz ‚his·tə′rē·səs ‚tes·tər]
(engineering)
An instrument for determining the hysteresis loss of a specimen of magnetic material by measuring the deflection of a horseshoe magnet when the specimen is rapidly rotated between the poles of the magnet and the magnet is allowed to rotate about an axis that is aligned with the axis of rotation of the specimen.