Aluzinc a game changer for MCCS
29 March 2019 | Web Article Number: ME201914053
THE replacement of steel by aluzinc in the manufacture of Shaw Controls motor control centres (MCCs) is giving a range of benefits to the company’s customers, according to the Senior Manager Operations, Anderson Kohler.
“Traditionally, we used only steel for our MCCs, which needs to be powder coated in order to protect it from corrosion. This made it necessary to follow quite a long process in completing our products – a process which aluzinc can now simplify and speed up,” Kohler said.
The usual process of preparing the MCC panels includes welding, grinding and prewashing before the powder coating painting process can take place. These phases can now be bypassed by using aluzinc which is a material that effectively resists corrosion without a protective coating being applied.
Kohler said the extended lifespan of Aluzinc - which comprises 55% aluminium, 43,5% zinc and 1,5% silicon - allowed manufacturers of the product to guarantee that it would last for about 35 years before any major maintenance was required.
“The powder coating of steel panels complicates the earthing requirement on an MCC, as the paint layer insulates the panel and prevents conductivity. This means that technicians and installers must take special care to ensure that proper contact is made between the unit and the earth connection.”
For instance, the use of star washers must be strictly enforced among installation staff. Alternatively, certain areas of the MCCs are left unpainted to allow for earth connections. Kohler said this raised the concern that it only takes a small oversight for the earthing not be fully effective. The use of aluzinc eliminates this issue as there is no longer a paint layer between the earth connection and MCC panel.
There is also the possibility of painted parts being scratched or damaged during transport and installation. When this occurs, it leads to the time consuming task of being returned to the factory for proper powder-coating, further delaying the installation and commissioning process. “Indeed, if there is a need to weld again for any reason, then there is a repeat process of grinding and pre-washing before painting again.”
Kohler said the corrosion-resistant properties of aluzinc allows parts to be kept in stock, ready for quick assembly, something not possible with mild steel due to corrosion.
“By introducing the use of aluzinc in the manufacture of our MCCs, we can reduce the lead time on components by as much as two to three weeks, and this is a time-saving that we can pass on to our customers by delivering more quickly.”
Kohler said there were also environmental benefits to using aluzinc as a replacement. No welding means a saving on gas and electricity, for instance, while no pre-washing obviates the need for harsh chemicals. In the painting process, there is invariably waste created through surplus paint that must be carefully disposed of in terms of environmental regulations.
Shaw Controls has over 30 years’ experience as a manufacturer of quality motor control centres (MCCs), distribution boards, medium voltage (MV) switchgear, control desks, PLC and instrumentation enclosures, portable and containerised substations, E-Houses and various other electrical enclosures. The company’s Robertsham facility is ISO 9001 accredited.