| 摘要 |
<p>PURPOSE:To simplify and miniaturize apparatus constitution and to detect abnormality with high accuracy by performing the differential operation of a supply current value at the time of connecting an electric welded joint and always performing monitoring. CONSTITUTION:The current from a power supply and a control apparatus 1 to an electric welded joint 10 is measured by an ammeter 2 and converted to a digital signal by an A/D converter to be sent to a discriminator 4. The sampling cycle in this case is set to 50msec or less to perform high speed processing. In this discriminator 4, the change state of a signal is monitored by a differentiation method and the presence of abnormality is discriminated when the differentiated value is positive, that is, a current increases. At the point of time when abnormality is discriminated, an alarm signal is sent to a relay 5 to cut off the supply of a current to the electric welded joint 10 emergently. By this method, welding inferiority is eliminated. Since apparatus constitution is simple, an apparatus can be made inexpensive and small-sized.</p> |
