Motrac Hydraulics continues on its new course with Shaft generator
Two years ago Motrac Hydraulics told a special story about eco-design: a better, greener design that also saves money. Motrac's branch office Hydromarine had developed a PTO-driven hydrostatic on-board generator. The problem with existing systems was that they had limited power and showed an unstable frequency. Motrac was able to develop a shaft generator of 75kVA with a stable frequency. Meanwhile, we are two years further and Motrac has successfully delivered the necessary systems, including a large 120kVA system. This success encouraged the company to develop a full range, to serve the market further. In future you will find the new range at Motrac under the name EcoGenDrive.
Deeper into technology
With the EcoGenDrive shaft generator, a Power take-off (PTO) takes mechanical power from the propulsion engine. A hydrostatic drive drives the generator to the desired frequency. The special thing about this concept is that the hydraulic system is built on the basis of a closed loop system with a pump with a variable output. This means that the piping of pump and motor are directly coupled, without the intervention of valves or control valves, which significantly increases efficiency. Only a limited volume of flow is used to cool the heat generated from the oil. Due to the hydrostatic drive, the generator speed does not depend on the diesel engine speed. This makes it possible to use the complete generator power under any desired sailing condition.
What makes the system unique is that the frequency remains stable under both varying loads and changing speeds. This is made possible by an electronically adjustable Linde pump and a very fast Völkel controller, and more than 60 years of experience in Linde hydraulics. Because Motrac is active in various markets, the company can utilize experiences from other markets. Especially for this system, Motrac has used an adjustment in the Linde pumps to be able to adjust the output extremely quickly and thus to be able to respond accurately to changing conditions.
Green sailing and cost savings go hand in hand
The closed hydrostatic drive ensures an efficiency which is considerably higher than that of a conventional hydraulic system. Above all, it is a reliable, sustainable solution that can save on costs. The use of this shaft generator, instead of a conventional diesel generator, leads to considerable savings in fuel. The main engine has a more efficient consumption per kW than a smaller diesel generator. Lower fuel consumption leads directly to a reduction of harmful emissions, giving the system a green character. Because no running hours are made with the diesel generator during the voyage, this directly reduces costs for the maintenance of the ship. The EcoGenDrive shaft generator shows how economic benefits and reduced environmental impact complements each other perfectly. The shaft generator is on the 2020 energy list for energy investment deduction (EIA). This allows you to benefit from tax deduction. More information can be found on the site www.rvo.nl code: EIA 240609
The shaft generator is available in four models EGD40, EGD65, EGD85 and EGD120. The models are equal to the available power and are available in both 50Hz and 60Hz. The starting point here is the ideal pump-motor combination, even though this also depends on the speed of the PTO. The EcoGenDrive shaft generator is supplied with a well-known Stamfort generator. Because there is no change on the generator side compared to a conventional diesel generator, you can also expect the same performance with regard to starting currents. The connection is also virtually identical. Because a traditional generator is used and the current is not generated by means of an inverter, the short-circuit resistance is guaranteed as one is accustomed to on board. In the coming period, Motrac will further expand the possibilities of synchronization, parallel operation and load sharing.
Teamco Shipyard B.V.
Teamco Shipyard has now embraced the eco-design concept. The company takes this concept into account with every new customer, according to Patrick Janssen - responsible for the reduction of ships at Teamco:
‘With the first installation we were very curious about the results’, says Patrick. ‘We also tested the generator extensively on board, switching the load on and off at varying engine speeds. Both we and the Electrical engineer were very surprised by the stability of the frequency. The frequency was even more stable than that of a diesel generator, and the sound was hardly perceptible.’
Patrick continues: ‘The set is easy to install. The pump on the PTO is large, but that is also necessary to be able to deliver the power at idling speed. On the other hand, the generator itself is extremely compact and you can always leave it somewhere in a corner. There is also no need for an exhaust duct and box cooler. It is important to pay attention with the hydraulic pipes; we placed the hydraulic oil cooler in the main engine LT-system, along with the fuel cooler and the gearbox cooler. So, one has to take care when measuring and fitting the pipes under the decking. Now that we know this, we can take sufficient account of it in advance. In general, it saves space in the engine room. Our upcoming projects are mainly tankers where a certain generator set-up is required to be able to pump in emergency operation. The shaft generator can be seen as a full-fledged generator, and therefore we can also handle the generator set-up cleverly on board in the future.
The advantages of the EcoGenDrive generator are clear to Patrick: ‘It's the cost savings which make the shaft generator so attractive, as well as savings on fuel and, of course, the lack of maintenance costs on a diesel generator. It is also a great advantage that this system reduces emissions and thus has a green image, but ultimately it is the cost savings that are the deciding factor. Our next three ships are destined for Chemgas; both are very important to them.’
Of course, you can always contact us for more information.
Motrac Hydrauliek B.V. / Hydromarine
T: +31 (0) 78 – 615 95 96