Attend the education session “Fundamentals of Hydraulic Systems 101” on Monday, March 9 from 8 a.m.-12 p.m. at IFPE 2020IFPE college courses offer professional development hours (PDHs), and interested individuals are encouraged to sign up now.


By Dr. Medhat Khalil, Director of Professional Education and Research, Milwaukee School of Engineering (MSOE)

Fundamentals of Hydraulic SystemsIt’s a common question that often arises when considering power transmission options: Which is best – mechanical, electrical or fluid power systems?

The short answer? None. Why? Because when one considers all points of view or all possible applications of a system, one is not definitively better than another. However, there is consensus regarding which specific system works best for certain applications.

When it comes to fluid power, hydraulic systems are known to provide greater power density and less energy density when compared to electrical systems. And to better understand these terms, the upper part of the figure shows a side-by-side comparison of a hydraulic motor and an electric motor that has the same power capacity. What’s obvious is the electric motor is significantly larger than its hydraulic counterpart. In this particular case, it has 10 times the weight and size of the hydraulic motor, meaning the hydraulic motor has a greater power/weight ratio.

Also known as specific power or power density, power/weight ratio is very important for mobile machines, since it directly affects compactness. The higher the power density value, the more compact the machine. As a result, the ability to fit more power into less space justifies the wide use of hydraulic systems for earth-moving and aerospace applications.

Now let’s try to understand this property from another angle. Consider hydraulic motors and electric motors of the same size, as shown in the lower part of the figure. It indicates a hydraulic motor receiving pressurized fluid with pressure of 300 psi can produce the same amount of power as an electric motor of the same size. The average working fluid pressure in hydraulic systems is 3,000 psi, which means a hydraulic motor can have 10 times the power capacity of an electric motor of the same size.

About the Education Session

KhalilDr. Medhat Khalil, who boasts more than 30 years of experience teaching fluid power for industry professionals, will conduct an education session – “Fundamentals of Hydraulic Systems 101” – at IFPE 2020 in Las Vegas, Nevada on Monday, March 9 from 8 a.m. until 12 p.m. in the Westgate Ballroom E-F.

Geared toward professionals seeking to achieve a greater understanding of the principles of hydraulic control and improve their practical skills in building hydraulic machines, the session will cover the following:

  • Reading hydraulic schematic diagrams
  • Predicting pump efficiency under specific operating conditions
  • Drawing the power distribution for the duty cycle of a machine
  • Investigating the losses in a hydraulic system
  • Building hydraulic circuits using different concepts

Hydraulic system builders and users will also find this education session beneficial in aiding their understanding of the operating principles of hydraulic components, using the right terminologies, determining the proper specifications of a hydraulic component, and much more. 

Dr. Khalil’s presentation has been excerpted from a reference book he authored, entitled “Introduction to Hydraulics for Industry Professionals.”

For more information on IFPE 2020, visit  

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