Crane Duty Helical Equipment Boxes
SELECTION PROCEDURE
Satisfactory performance of the gearbox is dependent upon correct selection. Selecting a gear unit is influenced by the class of duty of the crane that ought to be determined and specified. Single, Dual and Triple stage Horizontal gear systems type HA, HB and HC are suggested for Hoist and Long Travel drive. Three stage vertical equipment products type VC are suggested 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 necessary for the prime mover.
3. Refer to the rating table, find in the ratio column and based on input rpm examine the gear box ranking horizontally for various class of duty of the crane.
4. The size ought to be selected such that the ranked HP is equal or even more compared to the consumed HP.

EXAMPLE
1. Select a unit to transmit 9 HP from 720 rpm electric motor for hoist drive in a class II duty crane, the crane duty helical gearbox decrease ratio required is 31.50.
· For hoist drive a two stage horizontal gearbox type HB will be suitable.
· See the ratio column and in the size HB-350, for insight rpm of 720 in class II duty the rated HP is 9.5
· Since the consumed HP is certainly 9, the machine HB-350 will become suitable.

2. Select 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 become suitable.
· See the ratio column and in the size VC – 32Q, for insight rpm of 960 in class IV duty the ranked HP is 3