Crane Duty Helical Gear Boxes
SELECTION PROCEDURE
Satisfactory performance of the gearbox is dependent upon correct selection. The selection of a gear unit is definitely influenced by the class of duty of the crane that ought to be determined and specified. Single, Dual and Triple stage Horizontal equipment devices type HA, HB and HC are recommended for Hoist and Long Travel drive. Three stage vertical equipment devices type VC are recommended for cross travel drives of the EOT crane. Assembly arrangement should be specified while buying the gear units.

1. Compute the mandatory reduction ratio.
2. Determine the horsepower required for the prime mover.
3. Make reference to the crane duty helical gearbox rating desk, discover in the ratio column and based on input rpm verify the gear box ranking horizontally for various course of duty of the crane.
4. The size ought to be selected in a way that the ranked HP is equal or more compared to the consumed HP.

EXAMPLE
1. Decide on a unit to transmit 9 HP from 720 rpm electric motor for hoist drive in a class II duty crane, the decrease ratio required is 31.50.
· For hoist drive a two stage horizontal gearbox type HB will end up being suitable.
· See the ratio column and in the size HB-350, for input rpm of 720 in class II duty the rated HP is 9.5
· As the consumed HP is usually 9, the unit HB-350 will end up being suitable.

2. Decide on a unit to transmit 3 HP from 960 rpm electric electric motor for cross travel drive in a class IV duty crane, the reduction ratio required is 14.26.
· For cross travel drive, a vertical gearbox type VC will end up being suitable.
· Start to see the ratio column and in the size VC – 32Q, for insight rpm of 960 in class IV duty the rated HP is 3