Transformer tapping

What are the tap numbers? 
asked 11/23/2012
0

1 Answer

The nominal voltage of a transformer is related to the turns ration between the primary and secondary. In use the primary voltage can vary and the secondary current can vary. Both these will affect the output voltage of the transformer.

To cater for varying primary and secondary conditions, transformers are often fitted with taps on one of the windings; so that the turns ratio can be adjusted somewhat. These are often expressed as numbers.

For example, a low voltage transformer may have -5%, -2.5%, 0%, +2.5% and +5% taps. At 0% tap the transformer will be operating at its designed turns. At +2.5% the transformer secondary voltage will be 2.5% larger than what it would be if set at 0% (for the same primary voltage and secondary current).

An example of use would be setting a +2.5% or +5% tap on a transformer which is heavily loaded to help compensate for the voltage drop in the cables.
answered 11/26/2012 Steven McFadyen 246
Steven McFadyen

Your Answer

In order to provide an answer to this question, you must Login

I am flagging this question because...




10 inform moderator flags remaining

I am deleting this question because...




I am flagging this answer because...




10 inform moderator flags remaining

Flagging a Post

You have already flagged this post. Clicking "Remove Flag" below will remove your flag, thus reducing the count by one as well.

I am deleting this answer because...





DC Component of Asymmetrical Faults

The image (reproduced from IEC 60909) shows a typical fault in an ac system.  From the illustration it can seen that there is an initial dc component ...

Differential protection, the good old days

This morning I was explaining how differential protection works to a junior engineer. To give him something to read I opened up the NPAG (Network Protection...

Fault Calculations - Typical Equipment Parameters

A frequent problem in fault calculations is the obtaining of equipment parameters.  While it is always preferable to use the actual parameters of the equipment...

Generator Sizing & Operation Limits

When selecting a generator, there are inherent limits on the active and reactive power which can be delivered. Generators are normally sized for a certain...

Periodic Electrical Installation Inspection – How Often?

How often installations are inspected is up to the owner of the installation, provided such durations do not exceed any regulatory maximums in force. ...

IEEE Winds of Change

IEEE TV has a part series of videos on wind power and it's implication. For a really good overview to the technologies and issues around wind power, these...

Microsoft OneNote

A couple of months ago I came Microsoft's OneNote and downloaded the 60 day free trail. Since then I have been using it regularly and now have a full license...

Paths of Flight

GE have put together a time-lapse video shown flight take-off and landings at some airports. An interesting view:

Robots - Interesting Videos

The robot folding towels post below was interesting enough at the time to post a link.  Recently I’ve come across a couple of other interesting videos...

110 or 230 Volts

I've been considering a blog on the 110 or 230 Volt issue for a while.  While browsing the Internet I came across a great summary by Borat over at  engineering...

Our website uses cookies so that we can provide a better experience.
To learn more about what cookies are and how to manage them visit AboutCookies.org