Excellent post. I want to further support the importance of properly sizing the hydraulic pump for the machine. An inproperly sized pumped, as most of you know, can cause all sorts of expensive problems.
HYdraulics may be more efficient than some gearboxes, but in many cases the better efficiency would come from being 100% electric everything. What hydraulics can do very well is put the most energy in a small place, and a cylinder will live well even if you stall it So there is a time and place where hydraulic power is the best choice, but it is not everywhere. Most time changing to hydraulics is not done for efficiency.
Let's be clear here. This article argues that hydraulics are more efficient than GEARBOXES, not electric motors. Most hydraulics are powered by electric motors in the first place, and I am quite sure that a high efficiency direct drive brushless motor is more efficient than the induction motors usually used for hydraulics. However, if you have a gearbox in the drive train, you often lose 40% to the gearbox, and his points about bulk and weight are still well taken in certain applications. However, it is important that we think clearly about where the inefficiencies are or we will solve the wrong problem.
Good posting on this subject. I appreciate the comparison to electric systems and the benefits to be gained by applying hydraulics. I have long suspected that the trend to shift as much as possible to electric positioning systems and such might not always be the best approach.
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