Page 103 - Parker - AC and DC drives and motors

Application Profile

Hydraulic Power Unit

Parker VFD Saves on Energy

Consumption and Reduces

Audible Noise

Summary

Hydraulic power units are an ideal application for Parker Parker SSD Drives Solutions
variable frequency drives, which can run in setpoint
control mode. By receiving inputs representing flow
rate or pressure, the drive can maintain just the right
pump speed to accurately hold a setpoint. Higher AC690+ Integrator Series
efficiency gained by using the VFD results in less Process
heat to be dissipated. Benefits of noise reduction and AC890PX High
energy savings can be achieved on both variable speed Power Drive
pressure compensated and fixed displacement pumps. FUNCTIONALITY
AC650S
Example of energy saving Sensorless PMAC AC650V General
Tests run on a hydraulic press system clearly show Purpose High
that substantial savings on energy are possible using Performance Drive
the Parker variable speed drive to reduce motor speed
AC650G
during parts of the machine cycle with low flow demand. Simple General Purpose
Plus, by over-speeding a pump at times of low pressure
demand, a second pump could be eliminated. The result
in this case was an average power need of just 34 HP 10 HP POWER 150 HP 2000 HP
(25kW) compared to 50 HP (38kW) using an unregulated
pump, over the entire press cycle.

Benefits of variable speed drives in hydraulic systems

• Standard pumps can be used - fixed or variable displacement
Selection of system components
• Runs three phase motor from single phase supply (limited HP range)
• Longer motor service life, with unlimited starts per hour
• Less strain on the hydraulics, oil, and other components
Smooth acceleration and braking
• No power surges, no pressure surges (cavitation)
• Quick response to change in demand
• Savings on energy consumption, reduced peak power need
Higher efficiency
• Less oil heating/reduced need for cooling
• Smaller pumps and coolers needed
Compact dimensions • System takes up less floor space
• Reduced hydraulic oil volume
• Less need for noise protection
• Improved work environment
Reduced noise levels
• Reduced motor shaft rotations
• Smoothed resonant frequencies
• Less external hardware
Integrated concept • Simple customization, pre-engineered packages available
• Fieldbus options (Profibus, CAN, Ethernet, DeviceNet, etc.)
• Higher overall system efficiency
Frequency control • Increased productivity through higher motor speed
• Simple process diagnostics

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