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

1. Compute the mandatory reduction ratio.
2. Determine the horsepower required for the prime mover.
3. Refer to the rating table, see in the ratio column and based on input rpm examine the gear box rating 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 even 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 be suitable.
· See the ratio column and in the size HB-350, for crane duty helical gearbox insight rpm of 720 in class II duty the ranked HP is 9.5
· As the consumed HP is usually 9, the machine HB-350 will become suitable.

2. Select a unit to transmit 3 HP from 960 rpm electric motor for cross travel drive in a course IV duty crane, the decrease ratio required is 14.26.
· For cross travel drive, a vertical gearbox type VC will be 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