| 摘要 |
<p>An electrical control terminates the upset current of a flash welding process as a function of platen position. It comprises an operational amplifier which is used as a comparator. Voltage from a first source is fed to the comparator, this voltage being adjustable to provide for termination of the upset current at a selected position of the movable platen of the flash welder. Voltage from a second source is impressed upon a potentiometer and this voltage is varied in magnitude as the movable platen moves toward its closed position on the stationary platen. The variable voltage from the potentiometer is also fed into the comparator. When the algebraic sum of the voltage from the potentiometer and offset voltage of the comparator becomes of a magnitude (more or less) than the adjusted voltage from the first source, the comparator acts in the manner of a precision switch to set into operation means to terminate the upset current. <IMAGE></p> |
