ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
Increasing demand factors in residential
by gfretwell - 03/28/24 12:43 AM
Portable generator question
by Steve Miller - 03/19/24 08:50 PM
Do we need grounding?
by NORCAL - 03/19/24 05:11 PM
240V only in a home and NEC?
by dsk - 03/19/24 06:33 AM
Cordless Tools: The Obvious Question
by renosteinke - 03/14/24 08:05 PM
New in the Gallery:
This is a new one
This is a new one
by timmp, September 24
Few pics I found
Few pics I found
by timmp, August 15
Who's Online Now
0 members (), 255 guests, and 16 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
#129776 08/18/05 06:05 PM
Joined: Dec 2004
Posts: 1,064
D
Member
How does a Delta vs Wye change PF?

Any clues?


Dnk.....

Stay up to Code with the Latest NEC:


>> 2023 NEC & Related Reference & Exam Prep
2023 NEC & Related Reference & Study Guides

Pass Your Exam the FIRST TIME with the Latest NEC & Exam Prep

>> 2020 NEC & Related Reference & Study Guides
 

#129777 08/18/05 10:53 PM
Joined: Feb 2002
Posts: 182
B
Bob Offline
Member
How does a Delta vs Wye change PF?
It doesn't. Load has a specific PF. Voltage has nothing to do with it. A motor generally has a lagging PF and a capacitor has a leading PF. Check Here for more info. http://www.ibiblio.org/obp/electricCircuits/AC/AC_11.html


[This message has been edited by Bob (edited 08-18-2005).]

#129778 08/19/05 06:53 AM
Joined: Dec 2004
Posts: 1,064
D
Member
That's what I thought too.

I am doing PF testing and harmonics testing with a Fluke 434, and downloaded the new firmware to correct some bugs in it.

On a 480X240/120ct transformer I am monitoring, if you switch from delta to wye on the Fluke, the PF changes from .67 to .94.

I am curious why, they should be the same measurements unless somehow they get measured differently in the meter.

But that makes no sense..

Thanks.

Dnk.....

#129779 08/19/05 07:18 AM
Joined: Dec 2004
Posts: 1,064
D
Member
Or is it a Phase-Line PF, and then a Phase-Phase PF?

That would make sense, wouldn't it?


Dnk..

#129780 08/19/05 07:34 AM
Joined: Sep 2003
Posts: 650
W
Member
Only if the 'delta' connection tells the meter that the current sensors are in the phase to phase circuits, but the voltage connections are being made at the terminals.

Once you have the three conductors coming off the transformer, the power factor measurement should be the same.

-Jon

#129781 08/19/05 02:03 PM
Joined: Mar 2002
Posts: 582
R
Ron Offline
Member
A delta to wye transformer doesn't change the PF, but depending on how the meter makes the PF measurement, you may need to know that the delta to wye windings result in a 30 degree phase shift from primary to secondary.
Since PF is essentially measuring phase shift of voltage relative to current, that setting you describe on the meter may effect the reading.


Ron
#129782 08/19/05 03:41 PM
Joined: Dec 2004
Posts: 1,064
D
Member
It must be the phase-line reading, I measured another trans today and switched from delta-wye and the PF readings were about the same.

I will contact Fluke and let you know if your still interested.

Thanks for your help.

Dnk.....


Link Copied to Clipboard
Powered by UBB.threads™ PHP Forum Software 7.7.5