CVS Ferrari is one of the youngest companies to enter into the straddle carrier market and it is strongly convinced about the benefit that straddle carriers can have over others.
Advantages of straddle carriers
Straddle carriers are by far the most simple and effective system today available in the market for different reasons. First of all CVSF SC can do all the jobs and can be easily managed by Terminal Operation Systems with great saving in software management packages. Straddle carriers have higher flexibility compared to RTG or RMG handling systems since one can always decide to deploy the right number of units to handle, the quantity of containers one has to handle and they can be sent to all corner of the terminal.
They have higher productivity rates compared to terminal tractors since they can lift containers off the ground without the need of an STS operator and they can stack straight in the yard without the need of waiting for the availability of another machine (i.e. RTG or RMG). They have higher selectivity compared to again RTGs or RMGs since they can stack up to two or three high max, and can sort out a specific container in less time due to the higher travelling speed.
Since CVSF came quite late into this world, it was forced to bring as many innovations as possible in order to break through. Today CVSF is the only manufacturer able to deliver a straddle carrier one over two or one over three completely hydrostatic with the motors fitted straight inside the wheel hubs. This solution is recognised as a major innovation as it reduces the maintenance costs which had previously been due to frequent breakdown of those mechanical parts involved in the transmission of the torque from the engine to the wheels. The variable displacement pumps and motors fitted on CVSF hydrostatic machines have a lifespan of more than 24,000 hours before replacement.
Following the same concept applied to the hydrostatic version, CVSF has fitted the electrical motors straight inside the wheel hubs in order to save all the mechanical parts that often get extremely amaged during daily operations. The regenerative system fitted on the CVSF electrical straddle carrier will reduce by approx 10-15 per cent the fuel consumption compared to competitors. The use of the same type of permanent magnet motors for generating energy, for hoisting and for travelling will minimise the cost of the inventory in the spare part department. The use of can bus integrated management control means that the same CPUs are completely interchangeable all around the machine; another inventory cost savings.
On top of this CVSF has decided to use a latest generation motor. It is a ‘permanent magnet motor’ meaning the magnets mechanically fixed inside the rotor. This solution guarantees the magnets are better fixed, resulting in the possibility of using the motor at a higher rotating speed without the risk of loosing the magnets (this defect is present in motors using magnet fixed with glue or systems other than mechanical ones).
This solution also offers two other great advantages:
• The ability of blowing the cooling straight into the centre of the rotor where the temperature gets higher and the heat is generated
• The ability to use the same motor for a number of different applications inside the machine, as the range of rotating speeds offered by this motor varies from 800 rpm up to 9,000 rpm
This means the same motor is used for hoisting and for travelling where the rotating speed reaches 4,000 rpm and the same motor also is used for generating the electrical energy where the rotating speed can go up to 2,100 rpm.
In addition CVSF has designed the entire electrical system in a way that it is capable of regenerating energy developed by the motors when they are working as a brake (i.e. when lowering the load or when the machine is braking).
The savings in fuel consumption offered by the ability of reutilising the kinetic energy generated by the motors and transforming this into a sort of potential energy available whenever you need it, is the real challenge offered by the electrical straddle carriers. CVSF standard models are already capable of reutilising kinetic energy by absorbing it inside the bus capacitors on top of the motors and delivering it to the auxiliaries system fitted on the machine or using it for whatever combined movement desired.
In the future, electrical straddle carriers will change the ways machines are operated and they will pay back more as people will be able to lift the load while braking or accelerate while lowering the load. This virtuous way of driving will allow a higher fuel savings rate till the ability to store this kinetic energy in a different way becomes available.