Crane Duty Helical Equipment Boxes
SELECTION PROCEDURE
Satisfactory performance of the gearbox depends upon correct selection. Selecting a gear unit can be influenced by the crane duty helical gearbox course 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 recommended for Hoist and Long Travel drive. Three stage vertical equipment systems type VC are recommended for cross travel drives of the EOT crane. Assembly arrangement should be specified while purchasing the gear units.
1. Compute the mandatory reduction ratio.
2. Determine the horsepower necessary for the prime mover.
3. Refer to the rating desk, find in the ratio column and based on input rpm check the gear 
box rating horizontally for various course of duty of the crane.
4. The size ought to be selected such 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 decrease 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 course II duty the ranked HP is 9.5
· As the consumed HP is 9, the unit HB-350 will end up being 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 ranked HP is 3