Crane Duty Helical Equipment Boxes
SELECTION PROCEDURE
Satisfactory performance of the gearbox depends 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 gear units type HA, HB and HC are suggested for Hoist and Long Travel drive. Three stage vertical equipment devices type VC are suggested for cross travel drives of the EOT crane. Assembly arrangement should be specified while purchasing the gear units.

1. Compute the required reduction ratio.
2. Determine the horsepower required for the prime mover.
3. Refer to the rating table, find in the ratio column and predicated on input rpm verify 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 rated HP is equal or more compared to the consumed HP.

EXAMPLE
1. Decide on a unit to transmit 9 HP from 720 rpm electric engine for hoist drive in a course II duty crane, the reduction ratio required is 31.50.
· For hoist drive a two stage horizontal gearbox type HB will crane duty helical gearbox become suitable.
· Start to see the ratio column and in the size HB-350, for insight rpm of 720 in course II duty the rated HP is 9.5
· Because the consumed HP is usually 9, the unit HB-350 will become suitable.

2. Decide on a unit to transmit 3 HP from 960 rpm electric 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 course IV duty the ranked HP is 3