×
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

Jobs

Open Loop / Synchronized Conveyors

Open Loop / Synchronized Conveyors

Open Loop / Synchronized Conveyors

(OP)
We have three conveyors that are driven by one jack shaft.  We would like to install three individual variable frequency drive and motor systems and continue to synchronize these conveyors with an open loop control.  

Has anyone done this successfully?

RE: Open Loop / Synchronized Conveyors

Yes, this can be done. By "open loop", I take it to mean that you do not want to utilize feeback devices like encoders or tachometers. With a standard variable frequency/
variable voltage drive you could expect open loop speed accuracy of about 5-7%, with an open loop vector drive you could get down to 1% or so if everything is matched. That should be plenty for your application. I am using ballpark figures here and a general case. If you need specific info the manufacturer specifications will provide that or someone in this group may if you provide more specific information.    

RE: Open Loop / Synchronized Conveyors

I agree with Rhatcher that yep you can use an open loop control scheme. The numbers given are well in the order you should expect.
 BUT why??
Ensure that your application has some slippage and can tolerate some variation.
You have used the name 4 wheeler so take the analogy of a 4 wheel drive running on a sealed road. If there is a variation between front and rear wheels then something snaps.
The use of closed loop control provides some feed back and if tuned carefully will ensure you do not distort a "rigid product" like steel or paper.
 If you are conveying material like ore or coal go for open loop.

Regards Don
Ps to be very very very pendantic you cannot syncronise in open loop ie no feed back = no synch

RE: Open Loop / Synchronized Conveyors

Suggestions: Notice that
1. Encoders may be used in the "open loop" control as speed sensors and directly control motor speed. Two dependent motors on the third one could use encoders/speed sensors. One motor may be without any sensors.
2. Assuming a belt conveyor, even small difference in the roller surface speed and belt linear speed will cause friction and belt wear.

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!


Resources