Process automation of metal to Carbon relays: On — Line measurement of electrical parameters

The manufacturing process of Metal to Carbon relays used in railway signaling systems for configuring various circuits of signals / points / track circuits etc. consists of seven phases from raw material to finished goods. To ensure in-process quality, the physical, electrical and various other parameters are measured manually with non-automated equipment, after each stage. Manual measurements are tedious, error prone and involve lot of time, effort and manpower. Besides, they are susceptible to manipulation and may lead to inferior quality products being passed, either due to deliberation or due to malefic intentions. Due to erroneous measurement of electrical parameters, the functional reliability of relays is adversely affected. To enhance the trustworthiness of measurement of electrical parameters & to make the process faster, an automated measurement system having proprietary application software and a testing jig attachment has been developed. When the relay was fixed on the testing jig, the software scanned all the relay contacts and measured all the electrical parameters viz. operating voltage / current, contact resistance, release voltage / current, coil resistance etc. The result was stored in a database file and ported on an internet website. Thus, the test results of individual relays were available on-line, with date & time tags and could be easily monitored.