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

Minimum Arc Distance - ChemE needs some help from some EEs!

Minimum Arc Distance - ChemE needs some help from some EEs!

Minimum Arc Distance - ChemE needs some help from some EEs!

Hi - I apologize in advance in that I wasn't exactly sure in which forum to place this question.

Here is my scenario:

A 15 micron diameter tungsten wire will have 4700 Volts (DC) on it. The space between the wire and its surroundings is filled with clean plant air which is relatively humid – 60% rel humidity.

I have an ultrafine laser micrometer which I want to fixture around the wire as it passes from spool to spool (the wire conveys very smoothly so it doesn't bounce around at all) According to the drawing for the laser mic, I would have about 0.63 inches of clearance on each side of the wire.

Would this be enough gap to prevent an arcing event?

Your help will be greatly appreciated.

RE: Minimum Arc Distance - ChemE needs some help from some EEs!

I believe you'll be OK for the voltage and dimensions involved.  Check out Peek's equation which is an experimentally derived equation.

The main components are:

Ec - m E0 d K

Ec - corona onset gradient
m - shape factor = 1 for smooth cylindrical conductor
E0 - 21.1 kV / cm
d - relative air density
K - for small conductors, K = 1

Compare the result of this to the actual voltage a gap spacing that you have.

This is a pretty conservative approach.  If corona isn't likely from the values involved, you won't get a flashover either.

Probably should have posted this under electrical/electronic engineering other topics.


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


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