Crane Duty Helical Gear Boxes
SELECTION PROCEDURE
crane duty helical gearbox Satisfactory performance of the gearbox is dependent upon correct selection. The selection of a gear unit can be influenced by the class of duty of the crane which should be determined and specified. Single, Double and Triple stage Horizontal equipment models type HA, HB and HC are recommended for Hoist and Long Travel drive. Three stage vertical equipment models type VC are suggested for cross travel drives of the EOT crane. Assembly arrangement should 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 desk, observe in the ratio column and predicated on input rpm check 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 even 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 be 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 9, the machine HB-350 will become suitable.
2. Select a unit to transmit 3 HP from 960 rpm electric engine 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.
· See the ratio column and in the size VC – 32Q, for input rpm of 960 in class IV duty the ranked HP is 3