×
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!
*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

Cowbrush

thread1630-479033

Cowbrush

Cowbrush

(OP)
Hi there

We are 2 students from Belgium and we need some help with our project.
So our project is an automatic cowbrush. Maybe silly but I am a famrmer so it's usefull for the future. :)
So we don't know how to change the direction of our 3 phase motor. We also want that when there's to much resistance, the motor stops.
To build it in real life, it needs to be as cheap as possible. Is there anyone that could maybe help us? We would reaaly appreciate it.

Thanks in advance

F&S
Replies continue below

Recommended for you

RE: Cowbrush

Direction change during operation, ie backwards and forwards, is this what you are asking?

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

RE: Cowbrush

You should look up VFDs. That's what's needed for this project. About half of them have built-in PLCs that would allow you to program things like time on and reversing and stopping on too much load. They also allow you to bring the speed up smoothly instead of banging on and off and electromechanical forward and reverse contacts. A VFD also avoids chattering and over used contacts.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Cowbrush

Exchange or interchange any two of the three supply conductors and the motor will reverse.
If a motor is called upon to drive to much load, heat will be generated internally in the motor windings.
Light overloads may shorten the expected life of the motor.
Heavy overloads will lead to rapid motor burnout.
An industrial induction motor will typically stall at 2 times to 2 1/2 times full load torque.

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

RE: Cowbrush

Quote:

An industrial induction motor will typically stall at 2 times to 2 1/2 times full load torque.
And, if the overloads don't trip in less than 3 seconds the smoke will pour out of the motor.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Cowbrush

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

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


News
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