ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
Violation?
by renosteinke - 01/27/23 09:52 PM
Does NEC 551.71 (F) apply to dwellings?
by BigB - 01/20/23 10:46 AM
Power submeter connections
by HotLine1 - 01/19/23 09:09 AM
AFDD's coming to the UK
by Texas_Ranger - 01/17/23 07:22 PM
New in the Gallery:
Burger King crown sillyness
Burger King crown sillyness
by wa2ise, December 11
240/208 to a house
240/208 to a house
by wa2ise, October 9
Who's Online Now
0 members (), 115 guests, and 12 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
#214524 12/18/14 08:35 AM
Joined: Oct 2014
Posts: 5
P
PN1 Offline OP
New Member
Greetings fellow electricians and engineers. I have a question regarding EMS System filters( Adresses linear Vs Non linear loads). I have a project that requires an EMI fiter. The Characteristics are.

Max Applied Volts 230VAC
Operating frequency 50Hz
Maximum current Amperes 125Amps
Number of Phases 3

? How do I calculate the maximum value of the currents leakage ?
Regarding attenuation, How does one calculate the required attenuation ?.
Your opinions are much appreciated, Thank you.

PN1 #214543 12/20/14 12:34 AM
Joined: Jul 2004
Posts: 787
L
Member
Regarding attenuation, How does one calculate the required attenuation ?.

What frequency range are you trying to attenuate?

Is the product a variable frequency drive? They make line side inductors to smooth out the current spikes and reduce the noise getting into the power system from the VFD.

PN1 #214572 12/22/14 09:30 AM
Joined: Oct 2014
Posts: 5
P
PN1 Offline OP
New Member
The frequency is 50Hz. This is not a VFD, There are no potentiometers analog or PLC driven functions. Its a filter for RF emmanations. Its function adresses linear Vs. Non linear loads. Its basically a noise filter and transformer built into one unit.

PN1 #214577 12/22/14 09:09 PM
Joined: Jul 2004
Posts: 787
L
Member
A line filter and a transformer are two different things. I suspect you are looking for a three phase common mode choke.

CorCom is a common manufacturer here in North America.

Go to corcom.com and look thru their catalog. They have three phase line filters that may be just what you are looking for.

Joined: Jul 2004
Posts: 787
L
Member
More thoughts.

When filtering for RF emissions, make sure the noisy side of the power mains are separated from the shielded side of the power mains. Shielding may include a separate shielded compartment around the line filter and no mixing of the shielded side wires with the noisy side wires to prevent the RF interference from coupling onto the clean side.

To reduce radiated emissions from the system, tie all shielded cable shields to a 360 degree shielding bar before entering the noisy enclosure. Make sure that the longest dimension of the openings in the enclosure are less than 1/10(?) of a wavelength of the highest frequency of concern. Usually that means shielded fan grills and overhanging sheet metal so there is not a line of sight opening between the interior and the exterior of the noisy box.

Here is a good primer on shielding: EMI shielding primer

Good Luck

Larry

PN1 #214581 12/23/14 02:43 AM
Joined: Oct 2014
Posts: 5
P
PN1 Offline OP
New Member
Thanks Larry, Insight is much appreciated.

PN1 #214592 12/23/14 10:17 PM
Joined: Jul 2004
Posts: 787
L
Member
Your welcome.

Good luck with the project.


Link Copied to Clipboard
Featured:

Tools for Electricians
Tools for Electricians
 

* * * * * * *
2023 National Electrical Code (NEC)
2023 NEC Now Available!
 
* * * * * * *

2020 Master Electrician Exam Preparation Combos
2020 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
Alan Belson
Alan Belson
Mayenne N. France
Posts: 1,803
Joined: March 2005
Top Posters(30 Days)
BigB 9
Popular Topics(Views)
302,488 Are you busy
231,878 Re: Forum
216,501 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.5