| 摘要 |
<p>Electrical control system for supplying a predetermined amount of power to parts of thermoplastic conduits weldable by the Joule effect, stabilises by normal methods, the welding power, or the actual value indicated quadratically as J or U, of the welding current J or of th welding tension U. This may be effected by a regulator controlled by dephasing, at least approximately to a prescribed value, and the residual discrepancy in the value at any moment is compensated by the duration of welding so that the integral always gives, at least approximately, the value established for the joint in question. Method avoids the expense entailed in providing a highly accurate means of regulating the power supply with effective security against the possibility of errors. The objective of automatic control is achieved satisfactorily without more than normal commercial precision being called for from the different part-control circuits.</p> |
