Using current to test integrity of cable car wires. Ever heard of it?

[Ed.Kloonk]

Hi.

I just found out that the long steel wires that hold up the cable cars that span wide valleys are checked for strength periodically using electricity.

Do you know anything about this?

[jeroen74]

Maybe they use TDR, time-domain reflectometry, for that.

[SeanB]

More likely resistance measurement, and compensate for temperature. Then as the cable wears the resistance end to end will increase. Another method is to use the cable car to measure voltage drop over a length of cable as it travels along, and this allows the detection of broken strands easily by the step increase in voltage drop as the car travels over the breaks. Advantage is that you can do the measuring without disrupting operation, just pass a current of 100A or so through the cable.