Worked at nuke plant construction back in 70's. We needed to do a test pick with a 50ton 300' tall tower crane, wouldn't do it. Talked to manufacturer and they told us to turn field current up on 300HP DC winch motor. Stop broke on electronic board and motor went to 0 current,which meant motor let go of test load,110% of capacity,about 6"s off ground, That tower crane started swinging about 6' back and forth.wired rope spooling off drum like crazy,ruined it. Started this test at 7AM,this at 11PM,called it a day. Still would climb. Oh and was on top when it let load go.