A screw compressor with a variable speed drive (VSD) automatically adjusts the speed of the screw compressor according to the compressed air requirement and in real time according to demand.
VSD/PM screw compressors are designed for operations where the demand for compressed air fluctuates, depending on the flow demand of the compressed air users in the different processes.
In contrast to fixed-speed compressors, mostly V-belt driven propellers, which only run at full power, the VSD/PM screw compressor offers many advantages:
The VSD/PM screw compressor runs when needed, resulting in significantly lower energy costs, so the additional investment in VSD/PM technology pays for itself.
The VSD/PM screw compressor starts and stops under full system pressure, relief is no longer necessary, saving time as well as energy.
No time and especially energy is lost through unnecessary idling.
No blow-off loss occurs during normal operation.
Avoid fines from your energy supplier due to power peaks during (re)starting.
The pressure in the compressed air system is more consistent but also lower because the delta can be lowered, minimizing possible compressed air leaks.
This technology eliminates all the shortcomings of the conventional screw compressor for good and keeps energy costs manageable.
An additional element of VSD/PM technology is that you have to be fused considerably lower, also important when using power generators, here also a much lower starting load.
Energy saving is an important element in the choice of this technology
The largest cost component (about 70%) in the Total cost of ownership of an industrial screw compressor is not the machine itself, but the energy cost.
A VSD/PM screw compressor costs significantly more than a conventional fixed speed compressor, but this extra investment is quickly recouped through the energy savings.
VSD/PM technology can reduce the energy cost of your screw compressor by a factor of up to 50%.
This depends on the application and the capacity of the compressor.
The government and/or utility company may offer a discount or tax incentive to encourage your business to move to energy-efficient VSD/PM technology that helps reduce power consumption and minimize sudden spikes in demand.
The operation of the VSD/PM screw compressor
The variable drive saves energy by adjusting the speed of the compressor with a frequency control.
Unlike a conventional screw compressor, the PLC control supplies the VSD/PM screw compressor with the specific voltage required.
The system pressure and flow is measured in real time and this allows the integrated control to adapt the engine speed and torque to the actual air demand.
The idea is simple, but the technology behind it is highly advanced.
The PM motor with a voltage field between 300 and 450 volts is controlled by vector control technology with ultra-fast response time.
As a result, a high start-up impulse is obtained, and has less effect on the wear of the moving parts.
The insulation class IP-55 makes these compressors ideal for use in dusty environments (woodworking, sandblasting, demolition sites, etc.).
The heat generated is dissipated centrally through a temperature-controlled and over-sized air/oil cooler
The compressor automatically follows the compressed air requirement in both pressure and flow, which allows to work with a much smaller compressed air receiver.
By fixing the working pressure at 7 bar, you also avoid useless pressure build-up in the boiler.
The color touchscreen control panel is well-arranged and allows easy operation as well as a schematic representation of the compressor’s operation and maintenance schedule.
As an option you have the option to monitor your compressor via the internet.
The magic is in the drive, through the combination of motor and screw element.
VSD technology has the best results with screw compressors, because their flow rate and energy consumption are speed related.
If the speed of the motor is adjusted, the screw element also follows this 1 to 1, resulting in an adjusted compressed air flow.
The IE5+ Oil-cooled PM electric motor is specifically designed for this application, with regard to cooling and efficiency over the entire speed range.
Our latest VSD technology features an internal permanent magnet motor. (NdFeB)
In the VSD+ design, the PM motor shares the rotor shaft with the screw element, creating a direct drive that is particularly quiet and, above all, energy efficient.
Motor and screw element form a closed oil-cooled circuit.
This is also part of the energy savings achieved.
Finally, the new technology significantly reduces the required floor space compared to the conventional screw compressor.
A VSD compressor is by definition not designed to run continuously at full speed, even in a master/slave setup the VSD/PM compressor is the technology of choice to ensure optimal compressed air generation.