Crane Duty Helical Gear Boxes
SELECTION crane duty helical gearbox PROCEDURE
Satisfactory performance of the gearbox depends upon correct selection. Selecting a gear unit is certainly influenced by the class of duty 
of the crane that ought to be determined and specific. 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 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 mandatory reduction ratio.
2. Determine the horsepower required for the prime mover.
3. Refer to the rating table, see in the ratio column and predicated on input rpm verify the gear box ranking horizontally for various class of duty of the crane.
4. The size should be selected such that the ranked HP is equal or more than the consumed HP.
EXAMPLE
1. Select a unit to transmit 9 HP from 720 rpm electric engine 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 be suitable.
· See the ratio column and in the size HB-350, for input rpm of 720 in course II duty the rated HP is 9.5
· As the consumed HP is definitely 9, the unit HB-350 will become suitable.
2. Select a unit to transmit 3 HP from 960 rpm electric engine for cross travel drive in a class IV duty crane, the decrease ratio required is 14.26.
· For cross travel drive, a vertical gearbox type VC will be suitable.
· See the ratio column and in the size VC – 32Q, for insight rpm of 960 in course IV duty the ranked HP is 3