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Earth Leakage On Star-delta Close Transition, What causes the Earth Leakage on S/D close transition |
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 Jan 9 2008, 01:23 AM
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#1
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Junior Member  Group: Members Posts: 2 Joined: 9-January 08 Member No.: 4,175  |
I have a system using a star-delta close transition with resistor and capactior starter.
During the starting stage the earth leakage is about 9.6Amp! Is pretty high isn't it? The earth leakage relay is using a differential CT to measure my 3Ph 4 Wire, that is why it can detect the earth leakage during starting. After running it is back to normal zero leakage. Wire is fine and motor is fine. What could have causes the leakage current? |
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Jan 26 2008, 12:51 AM
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#2
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Intermediate Member Group: Full Member Posts: 31 Joined: 6-September 06 Member No.: 1,906 |
QUOTE (Gavin @ Jan 9 2008, 01:23 AM)  I have a system using a star-delta close transition with resistor and capactior starter. Can you explain the sistem? I dont know it! Saludos! Chris. |
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Jan 26 2008, 08:47 PM
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#3
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Posting Freak Group: Moderator Posts: 2,383 Joined: 24-April 02 From: Christchurch, New Zealand Member No.: 1 |
Hello Gavin
There should not be any earth leakage with a closed transition star delta starter. Earth leakage current would suggest that either the CT is in the wrong place, or there is a fault in the starter. Chris, for information on the closed transitions star delta starter, look here http://www.lmphotonics.com/star_delta.htm Best regards, -------------------- Mark Empson administrator
Skype Contact = markempson | phone +64 274 363 067 LMPForum | LMP Tech Warehouse | L M Photonics Ltd | Empson family | Advanced Motor Control Ltd | LMP Software | Mark Empson Website |
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Feb 5 2010, 06:31 PM
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#4
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Group: Members Posts: 1 Joined: 5-February 10 Member No.: 7,713 |
QUOTE (marke @ Jan 27 2008, 04:47 AM) Hello Gavin There should not be any earth leakage with a closed transition star delta starter. Earth leakage current would suggest that either the CT is in the wrong place, or there is a fault in the starter. Chris, for information on the closed transitions star delta starter, look here http://www.lmphotonics.com/star_delta.htm Best regards, Hello Marke, I am having the same problem as Gavin. However, I am using a auto-trans (closed transition) starter and there is nothing wrong with the starter. Any idea why there is an Earth Leakage only during the starting procedure before change over? Why is there such a high earth leakage during starting? The earth leakage was measured using a clamp meter at the earth wire. Could you kindly advise me on how I can resolve this problem? |
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Feb 7 2010, 09:14 AM
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#5
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Posting Freak Group: Moderator Posts: 2,383 Joined: 24-April 02 From: Christchurch, New Zealand Member No.: 1 |
Hello bringit
Switching will cause transient and step voltages which can be capacitively coupled to the frame of the motor. If there is a single impulse at the time of the switching, it is due to the capacitance between cables and earth and the motor windings and the motor frame. This is normal and not a problem. Best regards, Mark. -------------------- Mark Empson administrator
Skype Contact = markempson | phone +64 274 363 067 LMPForum | LMP Tech Warehouse | L M Photonics Ltd | Empson family | Advanced Motor Control Ltd | LMP Software | Mark Empson Website |
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Lo-Fi Version | Time is now: 3rd September 2010 - 05:13 PM |
