×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

*
*
*
*

Thanks. We have received your request and will respond promptly.

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

Non synchronous power sources

thread240-374918

Non synchronous power sources

Non synchronous power sources

(OP)
I am testing a transfer switch that is supposed to be able to handle two single phase sources that are asynchronous, and switch seamlessly from the first source to the second when the first one fails.

In our office we have a three phase supply. So if I took one single phase supply off red to use as the first source, and one single phase supply from the white phase as the second source, would these two count as asynchronous sources? Would their sine waves be in phase or not necessarily so?

RE: Non synchronous power sources

They will be precisely synchronized but always 120º out of phase. This will only show that your transfer switch can handle exactly one specific case. Using yet another phase will show that your switch can precisely handle exactly two cases. Not a very thorough test.

I hope your three phase is not delta...

Much better testing would be to use one of your building phases and then use a generator that is not synched to provide all other phase angle possibilities.

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

RE: Non synchronous power sources

A lot of equipment doesn't like an abrupt phase shift. Depending on the point on the wave that the phase shift occurs, you may trigger excessive transformer inrush and mechanical stress on motors, including broken shafts and high transient currents. Testing may not be trivial.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Non synchronous power sources

Sounds like a fairly stock standard static switch. It will have programmable parameters that let you adjust the amount of phase shift allowed for a seamless transfer, normally about 15 degrees is the maximum. Outside of that range, if there is a failure of the primary source the load will transfer, but with a break, again set by programmable parameters.

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

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