×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

problem operating 2 geared motors at the same time with one hyd pump

problem operating 2 geared motors at the same time with one hyd pump

problem operating 2 geared motors at the same time with one hyd pump

(OP)
i installed one hydraulic pump fixed displacement 25 gal/min.two motor spool v20 sectional valve bank .the motors must run independently w flow controles. the lift motor is rated at 16 gpm has 1" ports and 1/2"case drain.the flowcontrole for this motor has 3  3/4" ports.
the shaker motor rated at 6 gal/min has 3/4"ports and the flow controle has 3  1/2" ports.
the problem im having is when i run the two motors at the same time the shaker motor works great on #3 on flowcontrole however the lift motor runs les than half even with the flow control on all the wayand heres the wierd thing when i turn up the shaker motor the lift motor goes faster too. am i just missing something here?
any help would be greatly apreciated.

RE: problem operating 2 geared motors at the same time with one hyd pump

You are using bypassing flow controls.  When the shaker motor control is set to low flow excess flow from the fixed displacement pump is being dumped back to tank and little flow is avaialble for the lift motor.
When you increase the flow to the shaker motor the pressure rises also pushing more flow to the lift motor.
Where are the flow controls in the circuit?  Before or after the directional valves?
You would be better off with a tandem pump.  One side for the shaker and one side for the lift.  Split the pump, not the flow.

Ted

RE: problem operating 2 geared motors at the same time with one hyd pump

It seems you have connected both the Motors in Parallel Connection through control Valve.

Parallel Connections are more efficient only when load on each motor is same. Raising the pressure on one motor cause the other one less efficient & may disrupt the speed relation. you can increase the system pressure to increase torque of highest pressure motor. How about connecting both the motors in series.  speed of the motors can be controlled by bleed-off flow contol valve & torque can be adjusted by relief valves.


 
 

RE: problem operating 2 geared motors at the same time with one hyd pump

Do not connect the motors in series.  The motor shaft seals will not handle the pressure created by the downstream motor.
Do not manage motor torque with a relief valve.  Permit the system to deliver what the motors require at the flows delivered to the motors.
Use relief valves only to protect system components.
Bleeding off flow from an upstream motor will deprive the downstream motor of flow that may be required to reach desired speed.

Ted

RE: problem operating 2 geared motors at the same time with one hyd pump

(OP)
ted thankyou that makes sense the flowcontrols are after the spoolvalves. goes as such. from spoolvalve too in on flowcontrole then the controled flow goes to motor and from the motor back to spoolvalve the e flow on flowcontrole goes to tank. would it make any difference if i went straight to tank i wouldent think so since the return on the spool goes to tank anyways. is there anyway i can make this work or is there no way to?
kiran
these need to be independently controled the motors have two totally different loads and operate at different rpms so series is out of the question

RE: problem operating 2 geared motors at the same time with one hyd pump

Change out your pump to a tandem pump, two pumps on a common drive shaft.  Select each section to provide the maximum flow you want for each motor.  You will have two separate motor circuits.  Use separate directional valves.  You can use the flow controls to control the speed of each motor.

Alternatively, you can use a rotary flow splitter between the single pump and separate directional valves.  For about the same money as the rotary gear splitter you could just get a tandem pump to replace the single pump.

Ted

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

White Paper - How ESI is Helping Move New Medical Device Product to Market Quicker & More Cost Effic
Early Supplier Involvement has long been a strategy employed by manufacturers to produce innovative products. Now, it almost seems like a necessity. Because decisions made in the design phase can positively affect product quality and costs, this can help add value to OEM bottom lines. This white paper will discuss many facets of ESI, including why it’s so valuable today, what challenges limit the benefits of ESI, how cost is impacted, and more. Download Now
White Paper - Moving to a Driverless Future
This white paper describes what we see as the best practices to support a sustainable engineering process for autonomous vehicle design. It exposes how to use simulation and testing in common frameworks to enable design exploration, verification and validation for the development of autonomous cars at a system, software and full-vehicle level to drive a mature product development process for automated driving. Download Now
Research Report - How Engineers are Using Remote Access
Remote access enables engineers to work from anywhere provided they have an internet connection. We surveyed our audience of engineers, designers and product managers to learn how they use remote access within their organizations. We wanted to know which industries have adopted remote access, which software they are using, and what features matter most. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close