Crane Duty Helical Equipment Boxes
SELECTION PROCEDURE
Satisfactory performance of the gearbox is dependent upon correct selection. Selecting a gear unit is crane duty helical gearbox certainly influenced by the class of duty of the crane which should be determined and specified. Single, Double and Triple stage Horizontal equipment systems type HA, HB and HC are suggested for Hoist and Long Travel drive. Three stage vertical gear units type VC are recommended for cross travel drives of the EOT crane. Assembly arrangement must be specified while ordering the gear units.
1. Compute the required reduction ratio.
2. Determine the horsepower required for the prime mover.
3. Refer to the rating table, observe 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 should be selected such that the rated HP is equal or more than the consumed HP.
EXAMPLE
1. Select a unit to transmit 9 HP from 720 rpm 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 become suitable.
· Start to see the ratio column and in the size HB-350, for input rpm of 720 in class II duty the rated HP is 9.5
· Because the consumed HP is definitely 9, the machine HB-350 will become suitable.
2. Decide on 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 become suitable.
· See the ratio column and 
in the size VC – 32Q, for insight rpm of 960 in class IV duty the rated HP is 3