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 which should be determined and specified. Single,
Double and Triple stage Horizontal gear units type HA, HB and HC are
recommended 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
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 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 more
than the consumed HP.
1. Select a unit to transmit 9 HP from 720 rpm electric motor for
hoist drive in a class II duty crane, the reduction ratio required is
· For hoist drive a two stage horizontal gearbox type HB will be
· 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
· As the consumed HP is 9, the unit HB-350 will be 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 be
· See the ratio column and in the size VC - 32Q, for input rpm of
960 in class IV duty the rated HP is 3
As the consumed HP is 3, the unit VC - 320 will be