High-voltage motor supplied to recycler

Edited by the Engineeringtalk editorial team Jul 6, 2007

WEG has signed an order for a 4476kW 12-pole high voltage machine installed on a new GBP 7 million Lynx shredder owned and operated by recyclers H Williams and Son.

WEG UK has followed up its success in supplying a special 6865kW high-voltage electric motor for the world's largest industrial shredder, at Newport in Wales, with another major recycling order; this time for a 4476kW 12-pole high voltage machine installed on a new GBP 7 million Lynx shredder owned and operated by recyclers H Williams and Sons at Hitchin in Hertfordshire.

"This order was won on the excellent levels of reliability displayed by the motor supplied to Sims Metal at Newport", said Richard Emery, WEG MV/HV Product Manager.

"The Newport motor has to handle exceptionally heavy thrust loads, which can reach 116 tonnes on the motor drive end bearing; yet despite these operating conditions, it has proved to be 100% reliable".

The LynxS shredder purchased by H Williams and Sons is the latest design, allowing for improved yield of all metals.

It also contributes to the company's ongoing investment in technology to recover nonmetallic materials, such as plastics and glass, for recycling.

The primary crushing operation is complemented by air separation of heavy and light material fractions, followed by electro magnetic separation of the ferrous and nonferrous metals.

The final stage is the recovery of high-value metals from the waste stream by passing the waste through an induction field.

The role of the WEG motor in the shredder operation is to drive the hammers that crush scrap at a rate of up to 300 tons per hour.

Some 40% of the scrap is end of life cars, 40% household items and the remaining 20%, engineering scrap.

The 11kV motor is from WEG's M-Line, high voltage range.

M-Line motors are designed for larger applications in the output range up to 40MW and voltage range to 13.8kV.

They are used widely in demanding oil and gas and power generation applications worldwide, providing outstanding performance and high efficiency operation.

The M-Line motor on the Hitchin shredder has fabricated steel ribbed bearing housings for added strength.

It is also equipped with a forged shaft, and both of its main bearings are electrically insulated to ensure long-term reliability.

The motor has its own 33kV supply from a sub-station and is connected to an auto transformer.

It provides the drive for the shredder hammers via a fluid coupling.

The motor is started with the primary and secondary halves of the coupling disconnected, but when it reaches required speed, oil is pumped progressively into the secondary half of the coupling, connecting the two halves and providing an effective soft start for the motor operation.

The fluid coupling also provides protection in the event of the shredder jamming.

In such instances it will slip providing, in effect, a clutch mechanism that safeguards the motor.

"We know the people at Sims Metal and we respect their opinion, so when we asked them about using a WEG motor on our new shredder, we had no hesitation in taking their advice", said George Bond, Head of Operations for Metal and Waste Recycling.

"We have not regretted that decision; the WEG motor has operated with total reliability, running 10-hours a day, five days a week, since we commissioned it just over nine months ago in July 2006".

"The H Williams application is further endorsement of the performance and reliability of our high voltage motors in the most demanding of applications", said Richard Emery.

"Other companies have taken note of this, and the result is a high level of large machine business for WEG".