Crane Duty Helical Gear Boxes
SELECTION PROCEDURE
Satisfactory performance of the gearbox depends 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 specific. Single, Dual and Triple stage Horizontal gear systems type HA, HB and HC are suggested for Hoist and Long Travel drive. Three stage vertical equipment units 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 predicated 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 than the consumed HP.

EXAMPLE
1. Decide on a unit to transmit 9 HP from 720 rpm crane duty helical gearbox electric electric motor for hoist drive in a class II duty crane, the decrease ratio required is 31.50.
· For hoist drive a two stage horizontal gearbox type HB will end up being suitable.
· Start to 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
· Since the consumed HP is certainly 9, the unit HB-350 will end up being suitable.

2. Select 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 input rpm of 960 in class IV duty the rated HP is 3