Crane Duty Helical Equipment Boxes
SELECTION PROCEDURE
Satisfactory performance of the gearbox is dependent upon crane duty helical gearbox correct selection. The selection of a gear unit is usually influenced by the class of duty of the crane which should be determined and specific. Single, Dual and Triple stage Horizontal equipment devices type HA, HB and HC are recommended 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 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, see in the ratio column and based on input rpm examine the gear box rating horizontally for various class of duty of the crane.
4. The size should 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 electric motor 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 be suitable.
· See the ratio column and in the size HB-350, for input rpm of 720 in course II duty the ranked HP is 9.5
· Because the consumed HP is definitely 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 class IV duty crane, the reduction ratio required is 14.26.
· For cross travel drive, a vertical gearbox type VC will end up being suitable.
· See the ratio column and in the size VC – 32Q, for input rpm of 960 in class IV duty the ranked HP is 3