Film-Tech Forum ARCHIVE: Calculating 3-phase current

This is topic Calculating 3-phase current in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=002695

Posted by Rick Long (Member # 213) on 10-04-2001, 09:53 AM:

Does anyone remember the formula for calculating the current-per-leg in a 3-phase line? (Seem to remember a root 2 in there somewhere, but forget the rest of it).

For example, if I am running a 4 KW load from a 208-volt, 3-phase line, what current should I expect to see on each leg?

Posted by John Pytlak (Member # 331) on 10-04-2001, 11:58 AM:

Here's a link to the information:

http://www.chromaloxheating.com/technical/pdf/electrical.pdf

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

Posted by Evans A Criswell (Member # 381) on 10-04-2001, 01:37 PM:

quote:
Does anyone remember the formula for calculating the current-per-leg in a 3-phase line? (Seem to remember a root 2 in there somewhere, but forget the rest of it).

Actually, it's a square root of 3. In the document John linked to, everywhere you see a "1.73", that's the square root of 3, and if you want more accuracy than 3 significant digits (barely), use your calculator's square root feature.

------------------
Evans A Criswell
Huntsville-Decatur Movie Theatre Information Site

Posted by Rick Long (Member # 213) on 10-04-2001, 05:41 PM:

Exactly what I was looking for. Thank you John and Evans.