The ‘CARnivore’ With an Insatiable Appetite…
How the Power Electronics XMV660 Outdoor Variable Speed Drive calmed it down
About the client
Macaulay Metals, New Zealand’s largest privately owned scrap metal processor has recently commissioned a new shredding plant at their Seaview, Wellington site. The company employs 96 staff across their four North Island locations and exports more than 90% of the material they process.
Company owner Jeff Harris and Operations Manager Glen Jacobs spear-headed the new project which took seven years to realise.
The challenge: the search for a solution to limiting starting currents
Glen initially travelled the globe and located a low-hours secondhand shredder in Milan, Italy which would form the basis of their new processing line. The mill feeds a series of brand-new conveyors and downstream processing equipment from Lindemann / METSO which separates ferrous, nonferrous metals and ‘frag’ which is the non-metallic materials associated with the metal recovery process.
The plant operator sits above the matrix of conveyors and has full visibility of the total process from his state-of-the-art control station.
The shredder in operation. Note the operators cab high aloft.
The line can recover more than 30 tonnes of metal per hour and can digest a complete car in less than 40 seconds. To achieve this some serious energy is required. The shredder is powered by a 1,030 kW, 6 kV motor.
The Schorch 6 kV, 1030 kW main mill motor. (The mill is on the other side of the wall behind Glen)
The solution: the Power Electronics XMV660 outdoor Variable Speed Drive
The original mill was started direct-on-line and utilised a large fluid coupling to soften the mechanical stress when starting. This method of starting was not an option due to limited grid capacity so Macaulay, via their electrical engineers, Stephenson & Turner, approached Power Electronics for a solution. The Power Electronics XMV660 Outdoor Variable Speed Drive was selected. This limits the starting current to less than 1.5 times the full load running current and is within the 1.8 times maximum that the local Electricity Distribution Business stipulated.
The rugged XMV660 unit was initially to be installed outdoors saving specialist buildings and clean air environments that high voltage drives usually require. However, the VSD is now partially enclosed by a structure, but is still exposed to ambient dust and grime associated with a scrap metal yard environment.
Glen checks the XMV660
An innovative filter-less ‘cyclone drive’ cooling system delivers a constant stream of clean air to the XMV660. At the air intake, a labyrinth sifts the larger dust particles from the air stream, enabling the cyclone drive to eject the remaining contaminants. This ensures a constant flow of clean air into the electronics chamber and transformer cubicle without the need to maintain conventional dust filters.
Although the main mill motor is 6 kV, the XMV660 is connected to the 11 kV grid. The integral input phase-shift transformer offers a low THDi, high level electric protection, and high power factor at low loads.
The result: on-site and remote capabilities for all teams
Covid hit just as some 62 40’shipping containers of machinery were landed at the seven acre, Wellington site.
“Covid led to delays and presented challenges in site works, buildings and commissioning but we got there in the end,” Glen recalls. “At the peak of the construction, we had 32 contractors on site. Commissioning was carried out by one Lindemann engineer physically on site and MS Teams sessions with Europe and US-based personnel. A commissioning engineer from Power Electronics Spain was also scheduled to assist, but Power Electronics NZ engineers completed online factory training and utilised the ability for the XMV660 to be connected to the internet which enabled factory engineers to also be able to monitor the commissioning process from their base in Spain.”
Due to the high power consumption of the new line and other processing equipment at the Seaview site, the main shredder is operated outside of high grid usage times. Stephenson & Turner also specified two Sinexcel Static Var Generator power factor correction systems from Power Electronics to further maximise the available site capacity. These units maintain the site at close to unity Power Factor.
“We are really pleased with what we achieved,” Glen concludes. “It wouldn’t have been possible without the support and assistance provided by local contractors and suppliers”.
Learn more about the XMV660 outdoor variable speed drives