Medium duty or pulsating and varying loads without severe shocks
Generators ( varying load ). Reciprocating pumps. Mixers and pulverizers ( light ). Cranes & hoists ( varying heavy loads ) Conveyors ( varying heavy loads )
1.50
2.00
2.50
Heavy duty or severe shock loads High vibrations
Compressors ( reciprocating ). Crushers & Pulverizers ( heavy duty ), Hammer mills ( heavy duty ) Vibrating Screens
2.00
2.50
3.00
SELECTION PROCEDURE
Data required :
A. Power in HP
B. Speed in rpm
C. Shaft size of driver & driven in mm
D. Service factor (per guide)
Determine the 'SERVICE FACTOR' from guide chart given.
Multiply the service factor to the H.P. of the driver (eg. electric motor) to obtain the 'EFFECTIVE H.P.'
Refer the 'HP rpm' chart in 'TABLE T. Taking the appropriate rpm column, scroll down the column until the HP equal to or greater than the effective HP is located.
Ensure that the shaft sizes of your equipments are within pilot & max. bore sizes indicated in the same 'TABLE T .
If the shaft size are larger than the max. bore indicated, select from the next higher sizes of couplings where the shaft size is accommodated.
Thus the size of the coupling can be determined. The ' Type' of the coupling is at the discretion of the customer.
For rpm other than indicated, the effective HP can be determined by simple linear equation.
EXAMPLE
A) A coupling is to be selected to couple a centrifugal pump & an electric motor.
The Data is as below -
Power: 25 HP
Speed : 1500 rpm
Shaft sizes : Pump 28mm, Motor 48mm
From the 'SERVICE FACTOR GUIDE', the S.F. is 1.00. Thus, the effective HP is 25x1.00 = 25HP
From the Table 1, scrolling down the column of 1500 rpm, 25.5HP is located which determines the smallest
size of coupling which can transmit power of 25HP.
This coupling can take max shaft size of 48mm as required.
Thus, the size of coupling is '150'
B) If the shaft size in above application was say 55mm, size 190 coupling shall be appropriate.
NOTES
The angular shaft displacement should not exceed 1.5 deg. and parallel 0.38 mm for avoiding early failure of couplings.
While fitting couplings care should be taken so that the gap between jaw and body is maintained.
Couplings will be supplied with finish bore and keyway against specific requirements at extra cost.
