- Soken tester
Soken tester - is a portable single yoke instrument for assessing the
power lossin electrical steellaminations.
It has been developed for quick assessment of power loss in electrical steel sheet without the need for cutting and annealing, as it is the case for standardised methods like
The power loss can be estimated at 1.0 T, 1.5 T and 1.7 T and two frequencies 50 Hz and 60 Hz. Lamination thickness can be set within a range from 0.01 mm to 0.99 mm and there is no option for selecting the material
density. [Jeremy P. Hall, Evaluation of residual stress in electrical steel, PhD Thesis, School of Engineering, Cardiff University, 2001]
The power loss is measured as a product of
magnetic fieldand flux density. Both these signals are detected from the magnetising yoke, which is contained in an aluminium head (55 mm in diameter as shown in the photo). The flux density is measured from a secondary winding wound on the yoke. For that reason there is a great influence on the measured values, hence great care should be taken that the measuring head is placed on a clean and even sample.
The manufacturers of the instrument claim that its
measurement uncertaintyis lower than 5% (as referred to results from Epstein frame). [Soken Direct Reading Iron Loss Tester (Model DAC-1R-1), User Manual, Yokogawa-Martron Ltd., 20 Park Street, Princess Risborough, Bucks., UK]
The Soken tester has been developed in the second half of
XX centuryinitially as a relatively cheap and easy to use analogue device, but recently also digital devices are available. [ [http://www.otdl.com/ir02.html Direct Reading Iron Loss Tester] ]
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