Ok! First of all u cannot find a motor of 4HP.The Full Load Current of a 3HP motor is 4.8A and a 5HP motor is 7.8A.U jst use the simple formula
P(kw)=1.732 X V X I X pf X Efficiency.
So, for a 4HP motor(although u cannot find it) change the rating of motor from HP to watt,voltage-415V,pf-0.8,Eff-0.8(assuming) and u jst calculate it.Thanks!!
Ok! how can u add some weight to the rotating shaft??
Basically the motor shaft is coupled to the pumps or conveyors or etc. Now when the motor is started then it is said that the motor is in load condition.In this condition two types of load acts on the motor shaft
axial load & radial load.
If the motor is started when the shaft is in de-coupled condition then it is said motor in no-load condition.
Thanks!!