In rail-related applications, electrical testing is not only essential to prove the safety and reliability of new and modified electrical systems, it can also be a valuable tool for the prediction and prevention of costly failures. This article explores some of the test techniques that are most applicable to the rail sector, and explains their usefulness.
Electrical test instruments that are of particular value in railway applications include insulation testers, battery testers, low resistance ohmmeters and time-domain reflectometers (TDRs). Such instruments are widely available and most organisations involved in railway projects are likely to have access already to some if not all of them. However, it is worth noting that older instruments in particular may not offer the full benefits that are provided by the latest products.
The best 1kV insulation testers, for example, provide an extended measuring range. Instead of simply indicating ‘infinity’ for insulation resistances above few tens of megohms, these testers give accurate and dependable readings up into the tens of gigohms range. This may not seem to matter, as an infinity reading surely confirms that the insulation is in satisfactory condition.