Electric Automation Forum
Forum » Power Supply » What are causes of 2MVA power transformer having low output?
Topics: What are causes of 2MVA power transformer having low output? on Power Supply
#1

# What are causes of 2MVA power transformer having low output?

What are causes of 2MVA power transformer having low output and what kinds of test I can perform on the transformer? Pls very urgent
08-27-2014 03:32 PM
Top #2
Akinwande,

First define "low output"; do you mean it won't carry full load or that the terminal voltage(s) aren't what you expect? A simple ratio test will tell you if the winding(s) are not open or shorted, and insulation resistance tests will tell you if the are any internal faults to ground. Next I would call Schneider's tech support hot-line.

Alan
08-27-2014 06:03 PM
Top #3
Dear Mr. Akinwande Segun Olalekan,
Please clarify what do you mean by saying "2 MVA power transformer transformer having low output". A Transformer, irrespective of its MVA rating doesn't have any OUTPUT. All it has is LOAD CARRYING CAPACITY.
In a way you can look at a Transformer as a MAGICAL TRANSMISSION LINE THAT HAS THE CAPABILITY OF PROVIDING DIFFERENCE BETWEEN SENDING END VOLTAGE AND RECEIVING END VOLTAGE AND THIS DIFFERENCE IS NOT DUE TO VOLTAGE DROP.
HOWEVER, THE MVA/KVA AT RECEIVING END IS THE SAME AS AT RECEIVING END, EXCEPT THAT LOSSES ARE TO BE SUBTRACTED FROM SENDING END MVA/KVA - JUST LIKE IN CASE OF TRANSMISSION LINE.
Please therefore clarify what actual problem you are facing.
The forum members would then be better placed to help you out with their suggestions. I would try too.
Best Regards.
08-27-2014 08:41 PM
Top #4
Go for at Ratioo check first V2/V1= N2/N1=I1/I2
Ok. Low output is tems of voltage or in terms of Load?
08-27-2014 11:37 PM
Top #5
chances are that output, he means load carrying capacity. whilst awaiting to give more details Olalekan. also give the voltage transformation ratio.
08-28-2014 01:55 AM
Top #6
If you are a qualified engineer, first go and ask your money back from the training institution because that should not be a question a electrical engineer should ask
08-28-2014 04:45 AM
Top #7
Thank you all @ Chris P Mr perfect
08-28-2014 07:27 AM
Top #8
It should be fairly simple to perform the more basic tests, such as voltage ratio and short circuit impedance.
08-28-2014 07:35 AM
Top #9
I'll assume low output means lower secondary voltage than expected. Do you know what the actual primary voltage is at the transformer terminals? If it's more than a couple percent off from the nameplate rating you should consider making an adjustment to the no-load tap changer to match the actual voltage at the primary terminals, assuming the transformer has one. Be careful that you don't adjust this so much that you have higher voltage than desirable at low load conditions.
Then, what is the power factor of your load? Transformer series impedance has a high X/R ratio (2MVA X/R should be around 8), and this causes the voltage drop across the winding to be much higher at lower power factor than it would be at unity. So take measures if you can (be wary of harmonic loads) to correct the power factor to a target of 95% and that should improve your voltage.
08-28-2014 09:08 AM
Top #10
Mr. Olalekan, if you have time to respond to the comment regarding knowledge of what might be arguably basic electrical understanding, can you provide more information on the problem based on questions above? What is meant by output (voltage), how long has the transformer been installed (is this a new installation or re-purpose for an existing transformer) and similar information.

I am sure Christo Pieterse does not consider himself perfect (who of us is) but there are often people who ask questions because they do not want to take the time to work out a solution themselves. This forum should not be a source of free engineering or an option to avoid doing the engineering a person needs to do as the responsible person for the company that they work for. There is an expectation that information provided in this forum is being used as general advice and does not constitute conclusions that can be taken without the receiving person doing their own work.