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

1. Compute the mandatory reduction ratio.
2. Determine the horsepower required for the prime mover.
3. Make reference to the rating table, see in the ratio column and predicated on input rpm examine the gear box rating horizontally for various course of duty of the crane.
4. The size should be selected such that the ranked HP is equal or even more than the consumed HP.

EXAMPLE
1. Select a unit to crane duty helical gearbox transmit 9 HP from 720 rpm electric electric motor for hoist drive in a class II duty crane, the reduction ratio required is 31.50.
· For hoist drive a two stage horizontal gearbox type HB will become 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
· As the consumed HP is 9, the unit HB-350 will be suitable.

2. Decide on a unit to transmit 3 HP from 960 rpm electric engine 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