×
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

testing motor direction

testing motor direction

testing motor direction

(OP)
I have been asked a question on motor rotation dose anyone know of a test the can tell the direction a motor will rotate when it is conected to a 3 phase supply with a known phase rotation (motor leads not marked)the question was asked to aviod starting large drive the wrong direction when connected to gear boxes with roll back protection

RE: testing motor direction

This appears to be a difficult case since there is no way you can determine the motor rotation direction without testing it; whatever it may require to implement it. Suggestion: The disangagemet of gear from the motor gearbox is a good idea. Another way would be to gradually apply increasing voltage while monitoring current in the motor leads. If the current increases more in one phase sequence connection than in the other, then the direction of rotation is incorrect. However, this could potentially damage your gear. It would have to be analyzed first whether or not it is safe to the gear.

RE: testing motor direction

The tester appears to be good up to 600V. The original post does not indicate the motor terminal voltage.

RE: testing motor direction

The tester will not be connected to the energized motor, so the voltage is irrelevant.  Test is done with the motor stationary - two tests at two different rotor angles, with the rotor shifted in the direction of correct rotation.  This particular tester is also used to determine system phase rotation and will have a limit of 600 V for this application.  I believe that this type of device will do the job for you, Brant.

Quoting from the website data :
"....Phase Rotation Tester permits the electrical contractor or industrial maintenance electrician to permanently connect and tape the terminals of the motor being installed, without having to first energize the motor by a temporary hookup from a power source, if available, to determine motor rotation. Therefore, the test set eliminates the need for temporary connections that can be time consuming, costly and quite hazardous, particularly where many large, high-voltage motors are involved.

"Also, certain types of drives should never be rotated in the wrong direction. In such cases, the temporary hookup or trial method, having a fifty-fifty chance of being wrong, can do serious harm."

RE: testing motor direction

It appears that the input supply phase sequence at the motor terminals is needed to determine the motor rotation with respect to the motor supply phase sequence. What if is the supply phase sequence changed? Then motor will turn in the other direction. This would imply that the input supply phase sequence correlation the the motor direction of rotation is needed. This is why there is a concern regarding the complete determination of the motor run in the specified direction and associated motor rated/terminal voltage with respect to the mentioned meter 600V rating. There is to be noticed that the motor leads are not marked.

RE: testing motor direction

Original post states that the 3 phase supply rotation is known.  The test set identifies the correct motor lead connections to be matched to the known supply phase sequence to obtain the desired physical rotation.  
If the supply phase sequence is required, it is determined by using the meter up to 600V.  If the circuit voltage exceeds this value, then voltage transformers are needed to utilise the meter - note that this is a standard practical test used for determining phase sequence at any voltage.  If the circuit does not include VTs, then a temporary installation is needed.

RE: testing motor direction

who makes these testers and at what price are they ?
And are they available for d.c motors.

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 - Understanding Critical Specifications for Dynamic Metrology Applications
Different types of metrology have different critical specifications to consider when determining which actuator technology to use. This white paper goes into detail on the demands of dynamic metrology applications as they apply to the selection of precision linear motion control components and systems. In addition, the relevance of Moore's Law is examined in the context of the industry. Download Now
White Paper - Permanent Non-Welded and Cold Bent Piping Solutions
Commonly used welded piping connections come with skilled labor, validation, inspection, and long commissioning times, as well as the workplace hazards associated with welding. Non-welded permanent mechanically attached fittings offer a viable alternative to welded piping systems that greatly reduces the time to commission piping systems through reductions in many of the time-consuming steps required in welding. Download Now
White Paper - Take Mobile Hydraulic Systems to a New Level
The introduction of digital ecosystems connecting electronic control hardware and software to the Cloud is catalyzing a new era of mobile machine and equipment design innovation. This is enabling OEMs across industries to develop customized solutions that digitally integrate hydraulic and machine controls with the Internet of Things (IoT). Download Now
White Paper - The Evolving Landscape of Commercial Battery-Powered Trucks
What’s driving the evolving landscape of truck electrification? What are the barriers, motivators and strategies for accelerating the electric transition? What insights and resources are available for today’s design engineers working to achieve industry disruption and evolution? For answers to these and other pertinent questions, read this white paper. 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