It is very important to find out electrical parameters for an electrical engineer.
Very time installation of motor required certain parameters calculations which are stated as below:
Electrical Parameter to Find

Alternating
Current


SinglePhase

ThreePhase


Amperes when horsepower is known

HP x 746
E x Eff x pf 
HP x 746
1.73 x E x Eff x pf 
Amperes when kilowatts are known

KW x 1000
E x pf 
KW x 1000
1.73 x E x pf 
Amperes when KVA are known

KVAx 1000
E 
KVA x 1000
1.73 x E 
Kilowatts

I x E x pf
1000 
1.73 x I x E
x pf
1000 
KVA

I x E
1000 
1.73 x I x E
1000 
Horsepower = (Output)

I x E x Eff
x pf
746 
1.73 x I x E
x Eff x pff
746 
As from above we can find out ampere a motor can take. Day to day checking motor ampere is very much required for an electrical engineer.