Rolling mill motors (salient-pole synchronous and induction)
Two types of motors for variable-speed AC drives of rolling mills, salient-pole synchronous and squirrel-cage induction. The windings have VPI insulation, the shaft is made of high-strength forged steel, and supply is from a frequency converter. Used in hot and cold rolling mills, coilers and stands.
- Types
- salient-pole synchronous; squirrel-cage induction
- Synchronous
- roughing and finishing stands of hot rolling mills; unity cos φ
- Induction
- coilers and medium-power stands; torque at very low speeds
- Insulation
- VPI in a large autoclave
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
Variable-speed AC electric drives have become the priority technology for new rolling mills and their modernization. For such drives the manufacturer supplies motors of two types, salient-pole synchronous and squirrel-cage induction. They are supplied from a frequency converter. The choice of type depends on the stand. Where high torque and power are needed, synchronous machines are installed, while for coilers and auxiliary stands of medium power induction motors are sufficient.
Salient-pole synchronous motors provide high torque and power for roughing and finishing stands of hot rolling mills. They are easy to control and have high efficiency and a power factor equal to unity. Squirrel-cage induction motors are used for medium-power drives, including coilers and auxiliary stands. They are distinguished by a robust design, high torque at very low speeds and a wide constant-power control range.
The design is made for heavy duty. The end turns of the windings and the connections are reinforced with extra bracing to withstand electrodynamic forces during frequent reversals. In induction motors the brazing of the rotor bars to the short-circuit rings is designed for the repeated acceleration, braking and reversals typical of rolling production. A detailed analysis of the electromagnetic field and ventilation flows makes it possible to obtain a machine with maximum cooling and efficiency.
VPI insulation is carried out in a very large autoclave, so a stator of any size can be processed. The insulation is designed for the special duty and environment of a steel mill. The frame, rotor, shaft and bearings undergo static and dynamic strength calculation, and shafts are made of high-strength forged steel.
The motors work together with high-power PWM inverters for rolling mills. The manufacturer also offers induction motors for direct replacement of auxiliary DC motors of the rolling-mill type. They are used in hot and cold rolling mills, coilers, stands and metal processing lines. Power, voltage and speed are not specified in the materials provided, and these parameters are determined by the mill design. The choice between synchronous and induction versions is made at the design stage, based on the drive scheme and the stand load.
Technical specifications
| Types | salient-pole synchronous; squirrel-cage induction |
|---|---|
| Synchronous | roughing and finishing stands of hot rolling mills; unity cos φ |
| Induction | coilers and medium-power stands; torque at very low speeds |
| Insulation | VPI in a large autoclave |
| Shaft | high-strength forged steel |
| Duty | frequent reversals, acceleration and braking |
| Supply | from a frequency converter (variable-speed AC drive) |
Request a price and lead time
Rolling mill motors (salient-pole synchronous and induction). We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Questions and answers
Which types of motors are used in rolling mills?
Salient-pole synchronous motors for roughing and finishing stands of hot rolling, and squirrel-cage induction motors for coilers and medium-power stands.
Do the motors withstand frequent reversals?
Yes, the end turns of the windings and the connections are reinforced with extra bracing against electrodynamic forces. The brazing of the rotor bars is designed for repeated acceleration, braking and reversals.
What are the motors supplied from in rolling mills?
From a frequency converter in a variable-speed AC drive, together with PWM inverters for rolling mills. VPI insulation is designed for steel mill duty.
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