A : Manual release: The principle of manually releasing the steel ball is to suck the steel ball through the magnet on the handle, and then to separate the handle and the steel ball through the artificial external force, which will inevitably lead to deviation and rotation of the steel ball in the falling process. Causes the steel ball to come into contact with the wall and deviate from the center after it comes into contact with the specimen, and because each person or the same operator has different strengths for each operation, it will cause errors in the results and affect the success rate of the test. B : Electric release: The principle of electric release of steel ball is that the steel ball is fixed perpendicular to the electromagnet and fixed at the center of the Plexiglas tube. After the power is turned off, the electromagnet loses its magnetism and then falls freely. After the contact with the sample, it rebounds and greatly improves Test efficiency and data reliability. At the same time, it also satisfies the requirement that the steel ball falling in the standard does not allow rotation and is in the center position. Air-Cooled Condensing Unit,Air Cooled Condensing,Condensing Units Fittings,Heatcraft Condensing Unit TAIZHOU NANFENG COLD-CHAIN CO., LTD , https://www.windpolar.com