Efficiency of electric motors is around 95%. Procedure for design of any motor could be found out from any A.C machine design book, and soft ware programs are also available, if H.P/KW of motor is known, for rated frequency and voltage

In your case 1.5 ton load is not clear(British or Matric). Yet H.P/KW could be obtained(H.P=2(pie)NT/4500), if torque and speed is known. Speed is 60 R.P.M and rating is continuous, and torque needed for pulley of 1.5 meter would be Torque=(force)(liverarm)=((1.5)(1000)(1.5)), with properly selected unite sys.

Reduction gear would be needed for the motor design at normal frequency and hence the gear friction loss should be added.

Thank you Bhupendra Desai

My supplier suggested the 13HP induction motor with 8 pole and 50HZ rating,As per engineering design procedure 1.5 ton load requires torque of 2250 N-M but 13 HP provides only123.54 N M this not suitable as per theory, can you provide the detailed solution for this. let us take 8 pole 3 phase induction motor.

T1/T2=N2/N1, Use reduction gear, N1 the motor speed would be around 4% less than Synchronous Ns=120f/P