| 摘要 |
<p>The test head consists of a magnetic yoke. The yoke is excited with a.c. by excitation coils to such an extent that the metal strip under the yoke is magnetically saturated, while the yoke cross-section is such that it itself is not saturated. The excitation current amplitude, shape and frequency are so varied by a control circuit, that effects of rolling speed, strip temperature, eddy currents and strip tension are eliminated.</p> |
