adkrr64 What voltages are involved in the locomotive MU cables? Those get plugged/ unplugged all the time without any special precautions to power them down.
What voltages are involved in the locomotive MU cables? Those get plugged/ unplugged all the time without any special precautions to power them down.
According to this, 74 volts DC. Something else to consider, I believe the MU cabling is all signal and control, and not providing significant power to anything so wouldn't provide much current, whereas the ECP brake cable would have to provide enough current to power 200+ brake controls.
I just asked someone who would know, but he's not here on the forum. I'd guess nothing over 72VDC.
Edit: MU cables carry 74 VDC control voltages, at least in the old stuff we run. I'd have to believe we could still MU our old ALCOs with anything modern.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
tree68 adkrr64 What voltages are involved in the locomotive MU cables? Those get plugged/ unplugged all the time without any special precautions to power them down. I just asked someone who would know, but he's not here on the forum. I'd guess nothing over 72VDC. Edit: MU cables carry 74 VDC control voltages, at least in the old stuff we run. I'd have to believe we could still MU our old ALCOs with anything modern.
74VDC. And they don't carry for more than a dozen or so connections, reliably. RRs have rules about how many locos can be MUed. Also, you have to do a continuity check every time you build a consist.
MU connectors and cable do fail and get burned contacts, but they are pretty reliable - they also "fail safe".
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
oltmannd tree68 adkrr64 What voltages are involved in the locomotive MU cables? Those get plugged/ unplugged all the time without any special precautions to power them down. I just asked someone who would know, but he's not here on the forum. I'd guess nothing over 72VDC. Edit: MU cables carry 74 VDC control voltages, at least in the old stuff we run. I'd have to believe we could still MU our old ALCOs with anything modern. 74VDC. And they don't carry for more than a dozen or so connections, reliably. RRs have rules about how many locos can be MUed. Also, you have to do a continuity check every time you build a consist. MU connectors and cable do fail and get burned contacts, but they are pretty reliable - they also "fail safe".
All depends on what the definition of SAFE is.
https://www.ntsb.gov/investigations/AccidentReports/Reports/RAR0202.pdf
Because of MU failure engineer only had Dynamic Braking on the lead unit, not all three units like he thought.
Never too old to have a happy childhood!
When an engine is acting up for no obvious reason, pull the MU cable and see if that helps. Many engines now have a dummy receptacle for both ends of the MU cable. Sometimes leaving one end plugged into the live receptacle, even with the other end in the dummy slot can cause strange things to happen.
Jeff
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