| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an electronic balance in which a variable can be calculated accurately by preventing the temperature of a permanent magnet or a case from being elevated. <P>SOLUTION: An electronic balance 1 comprises a permanent magnet 6 which is fixed inside of a case 20, a lever 4 and a control unit 3. The lever 4 is supported to be oscillated by a fulcrum 8. In the lever 4, a measuring tray 9 on which an object W to be measured is placed is connected to one end portion, a movable electromagnetic coil 7 of an electromagnetic force generation device is connected to another end portion, and the movable electromagnetic coil is disposed inside of the case 20. In the control unit 3, an electromagnetic force generated by allowing a current to flow to the movable electromagnetic coil 7 is balanced with a load caused by the object to be measured and a variable is calculated from a current value required for balancing. A fixed electromagnetic coil 10 is further provided which is fixed inside of the case 20 and by allowing a current to flow to the fixed electromagnetic coil 10, the control unit 3 forms a magnetic field being opposite to and having the equal magnitude to a magnetic field generated by the movable electromagnetic coil 7. <P>COPYRIGHT: (C)2013,JPO&INPIT |
