Contact US

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

Brushless Servo Motor

Brushless Servo Motor

Brushless Servo Motor

Aside from resistance and insulation test, can you please give me an idea how to test a servo motor without using a servo driver. It is a 1.5hp, 0 to 3000 RPM.

Thanks a lot.

RE: Brushless Servo Motor

If you need to load test it without a drive, you will have to couple it to another motor and run it as an alternator, with a resistive load.  Without the load, you could at least check the open-circuit voltage, again with it driven as an alternator.

If you really want to keep it simple, try spinning it with a variable speed electric drill (possibly use a bit of sleeving eg heatshrink to couple the drill to the motor), that will give you the open-circuit emf - best viewed on an oscilloscope to check the waveshape and phase relationships of the output phase voltages.  The waveshape could be sinusoidal (a brushless AC motor and more common for a servo application) or more trapezoidal (classic brushless DC motor).  If you vary the speed you can plot voltage against output frequency, to give the o/c voltage-speed characteristic.  Of course, you ideally need to test against a known good motor.

RE: Brushless Servo Motor

Suggestion: It depends what is needed to be tested. Generally, tests can get very involved.

RE: Brushless Servo Motor

You can connect another motor or drill to the servo and drive the servo up to 1000 rpm and take voltage readings of the phases. This should give you the KE (Voltage Constant) of the servo. You could then compare it to the specs of the mfg to see if the mags haven't been damaged.

Cameron Anderson
Sales & Applications Engineer
"Dedicated to the Science of Motion"

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


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. 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