×
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

Using a servomotor (synchronous with permanent magnet) to generate a constant torque

Using a servomotor (synchronous with permanent magnet) to generate a constant torque

Using a servomotor (synchronous with permanent magnet) to generate a constant torque

(OP)
Hello,
I have a synchronous motor with permanent magnet. I want to use it as a "controlled brake", therefor it only have to generate a variable constant torque without fixing a speed.

I tryed to connect it with a resistance load through a 3 phase rectifier and then i modulate the resistance, but it only make a torque when it's short-circuited.
How can I do?

RE: Using a servomotor (synchronous with permanent magnet) to generate a constant torque

buy a servo drive that can operate in current or torque mode. there are zillions out there.

RE: Using a servomotor (synchronous with permanent magnet) to generate a constant torque

Your approach seems OK. But you have to consider the available voltage across the speed range you want to run. And also make sure that your resistor can "absorb" the corresponding current and power at lowest and highest speed.

It should work well also when not shorted. If the resistor isn't way too high valued.

It isn't as simple as buying one of the zillion servo drives. A PM motor usually needs an encoder or some other means of position/speed feed-back. There are encoderless servos, but not cheap and possibly not suitable for your motor.

What data do you have? For motor and resistor. What speed range are you going to run? And what torque range?

Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

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