In conversion technology, high energy efficiency and dynamics are equal requirements in the requirements specifications, even for very powerful applications. To meet those standards, Rexroth now optionally combines servo controllers or electronic frequency converters with axial-piston variable displacement pumps in the Sytronix variable speed pump drives family. These versions reduce energy consumption by up to 50% with significantly higher dynamics as fixed displacement pumps. Through intelligent energy management with the Smart Energy Mode software function, manufacturers are also able to reduce energy consumption for start/stop operations and highly dynamic applications. Direct comparisons show savings potential of up to 60% of maximum connected load.
In the combination of variable speed drives with fixed displacement pumps that have been common until this point, machine manufacturers increase energy efficiency, but also have to make compromises when it comes to high pressures and flow rates – especially in the case of fast load reversals. By using A4 and A10 series axial-piston variable displacement pumps in the Sytronix versions FcP 5000 and SvP 7000, Rexroth combines the energy savings potential with significantly increased dynamics. In contrast to fixed displacement pumps, the motor does not have to brake first for load reversals, reverse the rotational direction, and then re-accelerate the entire pump. Actually, it is sufficient to adjust the pivoting angle and pivot it through zero. With any rotational speed, the axial piston pump achieves the load reversal considerably faster than fixed displacement pumps.
Sytronix FcP 5000 uses a new, economical frequency converter series from Rexroth with an output of up to 90 kW. Sytronix SVP 7000 uses the highly dynamic IndraDrive servo drives of up to 630 kW output. As a specialist for drive and control technologies, Rexroth combines the best speed-torque-characteristics of electric drives with the ones of the pump´s performance in all Sytronix versions. To do so, the plug-and-play modules take advantage of the full performance of both components. In addition, the manufacturer integrates all fluid technology specifics into the drive software. Sytronix reduces noise emissions by up to 20 dB(A) and reduces cooling needs for the hydraulic medium.
Intelligent network management with Smart Energy Mode
In start-stop operations and highly dynamic applications in metal forming technology, the Smart Energy Mode software function is responsible for the intelligent energy management of the IndraDrive drives. The function combines two principles: the feed-in supply unit saves the energy recovered in braking operations in intermediate circuit capacitors. Feed-in/recovering supply units feed the braking energy back into the power supply and take power from the network again for the next acceleration processes. Smart Energy Mode creates a power voltage-independent intermediate circuit voltage while simultaneously using capacitors as energy stores. That avoids peak loads on the network side and reduces losses in the power supply system. With initial applications in punching machines, machine manufacturers were able to reduce the maximum connection power while maintaining the same productivity of 53 kW by nearly 60% to 22 kW. They reduced the intermediate connected load from 7.3 kW um approximately 30% to only 5.1 kW.
