Hello everyone,

A general question on testing hoist motor and gearboxes on gantry cranes.

A question came up about testing hoists with simply the lifting cradle or having a moderately loaded container on it to get a true reading of motor and gearbox vibration readings.

Now along with the same line would it be a better or more consistent method of reading vibration in the same direction rather then having the load coming up or down?

Historically all the readings have been done with simply the lifting cradle and in both direction's.

I am newish (2 years) at vibration and it seems to me that it would make sense to have a normal load and record in the same direction at every reading?



Original Post

I think you well understand the desirable testing plan would be at the same load, same speed, and same direction (2-tests). Tests could possibly be done when vessel is not present. You may be stuck with making measurements during normal vessel loading/unloading and have to cope with less than optimal operating conditions (union longshoremen)! You also have the issues of how comprehensive the measurements should be (number of points/directions and settings), climbing to top of gantry with instruments, and working in possible hostile weather condition! 

Good Luck,


Yes John, I understand the requirement for having the same conditions for every testing.

Unfortunately its not something that was done from the beginning of this survey program many, many years ago.

This is something I will have to discuss with the customer once I get my senior onboard with the changes.

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