Fault in Crane Wiring

Short circuits occur when +Volts are exposed to a difference of potential, not just earth.

The magnet cable doesn't last forever especially when you've got rough crane drivers. I would expect to change the cable once every 6 months.

Either one part of the part of the DC circuit is being connected to a common point allowing a short between the two magnet wires to have path back along the frame or the two magnet leads are getting touched together in a short circuit or there is a intermittent or partial internal short in the magnet itself that allows it to pull well past the fuses rating and blow them.

If your operators are rough with them they are also more than likely over running the duty cycle times to the point of burning them out and causing internal shorting problems.

For the life of me I've never worked out just how a crane driver managed to wrap the magnet cable around the winch drum.

They are a law unto themselves, nothing is safe from them!

We had one driver that when he was seen coming on shift the electricians would be making up spare cables.

Tonys thats funny :). Once our electricians are made to connect the cable three times in a shift.

The crane driver wouldn't be named Wilf would he?

He could wreck anything! Just try getting a 5-ton magnet out of the cab of a Scania artic. I've got to admit I was sat on the floor howling with laughter! Luckily the driver wasn't in the cab.

You know what we can't scold these guys or in case they become more rude in operating. They are in our department itself but they got their own union here. Our crane doesn't have a brake/thruster in LT and CT. They use revere control for braking like a drifting car. Does anyone use this method of braking

It's a standard method of braking the motors are designed for it. Brutal as it is it's the easiest way to drive a crane. Reverse braking is limited to a percentage of the motor full output.

We had two cranes on the one track. I'd got 45tons on the hook the other driver had 75tons of molten metal. Despite reverse braking there was an almighty clang when the cranes met! Each cane weighed in at 175tons never mind what was on the hooks. The 1000A breaker tripped due to both of us using maximum breaking

<...The crane driver wouldn't be named Wilf would he?...>

Or Homer, perhaps?