Can I get a 40KN force from a hydraulic cylinder powered by an electric motor?

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Discussion Overview

The discussion centers on the feasibility of generating a force of 40kN using a hydraulic cylinder powered by an electric motor connected to a car battery. Participants explore the requirements for motor and pump sizing, as well as considerations for efficiency and electrical specifications.

Discussion Character

  • Technical explanation
  • Exploratory

Main Points Raised

  • One participant proposes that it is possible to achieve any force with hydraulics, including 40kN, regardless of the power input.
  • Another participant calculates that raising a 40kN load over a specific distance in a given time can yield a power requirement of approximately 200W, suggesting a motor in the range of 300-400W to account for losses.
  • Concerns are raised about the electrical specifications, including the need for appropriate wire gauge and the potential for higher startup currents than the nominal 25A draw.
  • Efficiency of the motor and pump is suggested to be around 60-80%, which may impact the overall power requirements.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the specifics of motor and pump sizing, as well as the implications of efficiency and electrical considerations. Multiple viewpoints on these aspects remain present.

Contextual Notes

Participants mention assumptions regarding efficiency and electrical characteristics, but these factors remain unresolved in the discussion.

SteveAlex
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Im thinking of designing a tipping trailer for a car. I need a force of 40KN exerted to tip but would this be too much for driving with an electric motor powered by the car battery. If not what size of motor and pump would I need? thanks
 
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With hydraulics, you can get absolutely any force with absolutely any power input. You can hand-crank 40kN with hydraulics. In fact, I'm pretty sure you could find a hydraulic car lift that does just that.

Now, if you have a force, say these 40kN, and the time in which you want to raise the load a certain distance, you can get power. Say you want to raise 40kN load 1 foot in 1 minute. That works out to roughly 200W. Factor in loses, both mechanical and electrical, and you are probably looking for a 300-400W motor. At 12V, that works out to something in the 25-35 amp range. You should be able to draw that from a car battery.
 
Thank you for reply, very helpful
 
Just for completeness the equation K^2 is using is ..

Power = Force * velocity = force * distance/time

Force in Newtons
Distance in Meters
time in seconds
Power in watts

If drawing 25A think about the wire gauge needed and use appropriatly rated switch and fuse. A standard 30A rated switch might not last very long as the startup current could be much higher than 25A.

Perhaps assume the motor is only 60-80% efficient? The pump?
 

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