Conclusion

Compared to all variable-frequency drives, the particularity of rolling mills, which are frequent if not systematic, is the importance of their constant-power operation. We have explained the implications of this for machine design. The dimensioning of reciprocating machines, whether synchronous or asynchronous, in particular thermal, is very difficult to deal with in its entirety; the dimensioning variables being torque, speed, flux, and of course cycles. Temperature rise is related to these four parameters, but the thermal time constants, rotor and stator, are different and only known to motor manufacturers.

It was impossible to cover every type of motorization found in rolling mills, but without being exhaustive, we have described the most frequently encountered generic cases, from winders to hydraulic roll clamping.

We have used a simple,...