Hagglunds have long been known for producing large hydraulic motors, so large in fact that they can replace large gearboxes completely thereby offering a direct hydraulic drive to applications like conveyors, shredders, drums and winches. This enables the inherent benefits of hydraulics to be used for the first time in very large drive applications producing significant performance improvements.
The drive motors can produce very high torque from starting and throughout the speed range and so for example, starting a conveyor under full load is no problem. It can also be inched forwards and backwards, stopped and started as often as you like without limits because the control of direction and oil flow is achieved by the variable displacement pump alone, the AC electric motor runs efficiently at constant speed. The only need to stop the electric motor is when shutting down for lengthy periods. This opens up a new world of control on large machines.
More recent developments at Hagglunds has now produced motors that can even push the boundaries of conventional hydraulic drive engineering. The new CBP motors can operate at very high power due to the additional port plate designed into the motor enabling twice the flow capacity that was available before. Since power equals torque multiplied by the speed, by doubling the speed, the output power is also doubled whilst keeping the overall efficiency at very high levels. Such performance requires attention to other areas to achieve high integrity and reliability such as the shaft sealings and much testing has been going on in Hagglunds large laboratories in Sweden for the last few years. Indeed so much power to test is now needed for these high power CBP motors that new cooling systems taking water from a large nearby lake have been installed to cater for the high power testing needed. Don’t worry environmentally, the temperature of the lake has been calculated and the temperature rise will be insignificant to local fauna and flora.
This means that Hagglunds can now offer drive motors that can give a continuous power output of over one thousand KW or over one MW and still retain the favourable smooth reliable torque characteristics the Hagglunds have been know for, for many years. The motors have a maximum continuous pressure of 350 bar but normally the motors are sized for working pressures around 200 bar so this means that for the full power for just one motor, a flow of around 3000 lt/min is needed from the power unit. Obviously for a machine with two drives motors such as a typical twin rotor internal rubber mixer the flow would be double this.
To achieve 6000 lt/min flow you need 8 large pumps with a displacement of 500 cc/rev operating at 4 pole speed of 1475rpm. This is quite a formidable power unit.
To accommodate these high powers Hagglunds have developed a modular power unit system called Gemini. The system comprises the following modules –
• The power unit, which can comprise of several motor pump units.
• The tank unit, which supplies the hydraulic fluid and keeps it cool. It also has system monitoring with local controls and displays.
• The Service unit houses the filtration system where most of the routine maintenance occurs.
• The control unit is PLC based and controls the whole system using BUS technology with health monitoring and logging information for analysis.
• Piping and hosing is prefabricated flanged non welded of highest quality.
With such high powers now available applications such as renewable energy applications like wind and tidal can utilize these big motors to act as pumps to supply large axial piston motors driving generators.
Other applications are large overland conveyors, ship propulsion and process applications like chemical reactors and internal mixers.
The Gemini system loses non of the attractive features of typical Hagglunds drive systems with infinitely variable speed, the unbeatable power to weight ratio giving very compact space saving dimensions around the driven shaft area and very low inertia which means a very responsive drive to accelerate or decelerate, one that can stop very quickly if overloaded so preventing catastrophic failure of machine components because the torque absorbed is always kept under known limits by the fast acting pressure controls in the swash plate pump. If the drive is overloaded it will simply stall and hold the controlled torque so protecting the machine from unacceptable forces which with geared drives with massive inertia’s in comparison can cause expensive damage and plant downtime.
Internal rubber mixer
Internal rubber mixers are very intensive batch process machines with heavy duty requirements since solid rubber is fed into the machine with various other ingredients to mix together into various compounds for tyres and seals etc The Hagglunds solution enables variable speed ratio between the rotors on tangential machines so the speeds can be adjusted to suit the compounds being produced.
LKAB 1.8 km overland belt conveyor Lulea Sweden.
Belt conveyors are employed to move bulk materials economically and efficiently saving costs of truck haulage which can often have detrimental effects on the environment and local road infrastructure. This belt conveyor for small round pellets goes up and down hill with frequent starts and stops so a drive with very smooth speed control is essential to prevent the pellets slipping or running on the belt. The Hagglunds drive provides this with full torque available throughout the speed range so you can adjust the speed without concern about torque and the ramps are smoothly controlled within the Hagglunds control system.
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