The range of horsepower of electric motor drives for rolling mills is of the order of
Right Answer is:
100 to 500 HP
Rolling mills are generally classiﬁed according to their products, since, very often, a particular mill is capable of manufacturing a speciﬁc product, and the design of mill stand, mill head, auxiliaries and drives changes with the type of product.
The Rolling mill is mainly dependent on electrical energy and about 60 to 70% of electrical energy is spent on rolling operations and balance is consumed on an auxiliary operation like cutting of roll stock, furnace blower, crane operation, etc.
The motor of the rolling mill should possess the following characteristics
- Superior efficiency
- Robust frame and shaft construction to withstand the severest duty
- Less demand for maintenance
- The high degree of control and responsiveness
- Great capacity for acceleration and deceleration.
- Greater flexibility for extreme operating conditions.
- it should be capable of developing short-time torque to the extent of 2 or 3 times of rated torque.
- It should be capable of having wide speed variation.
- It should be in a position to maintain preselected speed within tolerances from no load to full load. Therefore it should have a quick response to change.
- The rolling mill requires a high-power motor generally dc motor and a slip ring induction motor of multi-kilowatt (above 100 H.P motor) is preferred.
- According to the survey of ROLLING MILLS IN RAIPUR. The normal sizes of electric motors ranging from 400 H.P. to 1000 H.P.