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Homework Help: Hydraulic Circuit Query

  1. Jul 21, 2015 #1
    < Mentor Note -- thread moved to HH from the technical engineering forums, so no HH Template is shown >


    I am struggling with a couple of questions and would like to check my working so far.

    Question 6:

    To explain the operation: I believe the electric motor turns the pump which draws hydraulic fluid into the system through component F (which one depends on the direction of the pump). This creates a flow, turning the hydraulic motor. Because the pump and motor can only accept a certain flow, as more fluid is drawn into the system pressure will build, causing Components B&C to open in turn. The fluid will leave the system through the variable restriction, but only at a rate which maintains the required pressure in the system.

    Is this a correct interpretation of the circuit? I am not sure how to explain Question 6 part c) regarding the limitations of speed control - can anyone help?

    I would say that because the Pressure Relief Valves will be opening and closing, it would cause a fluctuation in the speed at A?

    Question 7:

    I am struggling to know where to start on this question, any guidance would be appreciated.


    Attached Files:

    Last edited by a moderator: Jul 21, 2015
  2. jcsd
  3. Jul 21, 2015 #2


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  4. Jul 22, 2015 #3
    Sorry I am not sure which components you mean?

    My understanding was:

    A = fully rotational bi-directional fixed displacement hydraulic motor
    B & C = Pressure Relief Valve
    D = bi-directional fixed displacement hydraulic pump
    E = Electric motor
    F = Variable Restriction with Integral Non Return Valve

    I will admit I am not entirely sure how the PRVs operate in this circuit - do they simply open when pressure reaches a certain level or are they a holding tank?

    I would appreciate help to walk through how the system operates. I believe from there it will help me answer the follow on questions once I understand whether my interpretation of the system is correct.

  5. Oct 16, 2016 #4


    Do you have any thing to share from this?

    I have made further progress with the purpose of the components, understand to an extent how the circuit works but the Restriction valves image with the arrow is throwing me. They both point in the direction which the non returns open so would be redundant??

    Any tips would be greatly appreciated.

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