| 摘要 |
PROBLEM TO BE SOLVED: To monitor the error of the electrical resistance value of the heating wire of a fusion connected joint with the lapse of time by causing weak current as well as current more than the weak current to flow through the heating wire to find the electrical resistance values of the wire against each current, and comparing the difference thereof with the prescribed allowable value. SOLUTION: Controller terminals are respectively connected to joint connector pins at a step S3 and, then, weak current having amperage of several 10mA is made to flow across each connector pin for measuring voltage and finding the initial resistance value R1 of a heating wire itself at a step S4. Then, fusing current of 5.5A is made to flow and, thereafter, voltage across connector pins is measured at a relatively early stage, thereby finding a resistance value R2 during a fusing process at a step S8. Then, a ratio Z% of (R1-R2)/R1 is obtained from the initial resistance value R1 and the fusing resistance value R2 at a step 9. The ratio Z and the allowable value S2 of an error with the lapse of time are compared with each other at a step S10. Then, when the value of Z is equal to or above S2, an alarm signal for showing the occurrence of a connector abnormality is outputted to stop the current carrying. |
