Wonder drug for poor life expectancy

With good maintenance, structurally, a quayside gantry crane could remain in service for more than 40 years. But drive control systems are letting the team down, with a life expectancy of just 15 years.
“After 15 years, evolving technology and diminishing spare parts support means that the overall performance of a drive is less than satisfactory to the user compared to acquiring new equipment,” says Mr Tok Soon Chong of retrofit expert Portek.


Availability of spare parts becomes a major headache. Original or compatible printed circuit boards and their components may simply no longer be obtainable after 10-15 years, while not all manufacturers will support availability of spare parts for their products over such a long period.


“This results in crane downtime becoming a very serious economic factor,” says Mr Tok.


He adds that older cranes were also invariably designed with less mechanical and electrical protection, simply because the requirement to do so was less stringent. In contrast, modern programmable logic controllers (PLCs) and drive systems have built-in detection and interlocks which prohibit many unsafe operation.


The price of a drive retrofit is about 10%-15% of the cost of acquiring an entirely new crane. Furthermore, in many drive retrofit projects, crane owners take the opportunity to refurbish the entire crane, including making structural repairs and upgrading mechanical components such as the operator cabin, brakes, spreaders and so on. The total cost of retrofit, according to Portek, is therefore usually about 30% of the cost of a new crane.


“For a drive replacement on a quay crane, an operator would be looking at paying around $800,000 and for an RTG $300,000,” says Mr Tok.


Company president Larry Lam adds that the 15-20-year life extension to a crane that a drive change brings postpones a terminal's capital expenditure, while at the same time improving the performance, reliability and safety of the crane, which may generate lower insurance premiums.


“If it cost $800,000 to install a new drive and thereby extend the working life by 20 years then the terminal is effectively paying just $40,000 a year, which is a small price to pay given the advantages it generates,” he says.


Mr Tok nevertheless comments that, while a successful drive retrofit will ensure the electrical components of a crane will continue to give a good performance, it cannot exactly mirror the performance delivered by a brand new crane, since this will incorporate all new mechanical and structural components.


“However, all older cranes are suitable for upgrading with a new drive and Portek will retrofit any cranes that are structurally fit,” he says. “In addition, the company offers a 12-month guarantee on all drive retrofits that we undertake.”
(Source:http://www.portstrategy.com)