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gmanoj2020
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Join Date: Dec 2011
Posts: 4

Clarification Regarding Oversizing of Transformer

12/18/2012 11:47 PM

One of our Client Specification specifies the Minimum Rating of the Transformer shall be 1MVA.

But actual requirement of the transformer after Sizing doesn't exceeding 400KVA.

In this regard kindly clarify the Merits and Demerits while Over sizing the Transformer as per Specification need.

Also Clarify any IS or IEC specifications describes regarding Oversizing of Transformer.

kindly share your valuable points on Over sizing.
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Pathfinder Tags: Transformer Oversizing
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Joshi
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Join Date: Oct 2007
Location: India
Posts: 1246
Good Answers: 34
#1

Re: Clarification regarding Oversizing of Transformer

12/19/2012 12:34 AM

Your client is looking at, 'beyond his present requirement'. He may be considering of possible expansions in near future, that you are not privy to. In any case, when he is footing the bill, what is your problem? You may simply put on record, the present load requirement. It will be impolite to argue/force issues IMHO.
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gmanoj2020
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Join Date: Dec 2011
Posts: 4
#2
In reply to #1

Re: Clarification regarding Oversizing of Transformer

12/19/2012 1:46 AM

There is no Possibility of Expansion.

This is needed for standardization of Transformer rating according to specification point.
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Joshi
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Location: India
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#3
In reply to #2

Re: Clarification regarding Oversizing of Transformer

12/19/2012 1:57 AM

Then discuss with your client, over a cup of tea & win him over to your point of view.
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PWSlack
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United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

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#4
In reply to #2

Re: Clarification regarding Oversizing of Transformer

12/19/2012 3:21 AM

Well, that's an end to it, then. Provide the Client with what the organisation is prepared to pay for.

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silverfox
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#5

Re: Clarification regarding Oversizing of Transformer

12/19/2012 3:32 AM

I agree with the masses - the client has spec-ced it you need to provide it.

Agree the client may have a planned expansion you don't know of. Does he have any large DOL drives - fans are other drives that are bad to start. A system with constant brown outs because the transformer is undersized would be bad.
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gmanoj2020
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Join Date: Dec 2011
Posts: 4
#6

Re: Clarification regarding Oversizing of Transformer

12/19/2012 4:00 AM

Guys, it is clear there will not be any Expansion,

Let come out of Specification need and Explain the Merits and Demerits of Transformer Oversizing and any standard related to it
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RAMConsult
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Engineering Fields - Power Engineering - New Member

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Location: NYC metropolitan area.
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#8

Re: Clarification Regarding Oversizing of Transformer

12/19/2012 11:13 AM

The answer lies in your earlier response, "...This is needed for standardization of Transformer rating according to specification point..." Your client has a sparing policy that allows for easy and rapid replacement of a failed transformer because there are identical units in their inventory.

They are not concerned about the apparent oversizing because the continuity of their process is far more important, and downtime is far more costly, than the excess capacity.

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Snave
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Join Date: Oct 2007
Location: S. California, USA
Posts: 279
Good Answers: 12
#9

Re: Clarification Regarding Oversizing of Transformer

12/20/2012 12:00 PM

Advantages of over sizing (or de-rating) a transformer are:

  • Longer life as it operates at lower stress and runs cooler.
  • Improved voltage regulation as the change in voltage drop across the transformer is less as the load is changed.

Reason for this customer is expressed in your post (Post #2) and explained by RAM consultant (post #8), sparing.
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pnaban
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#10

Re: Clarification Regarding Oversizing of Transformer

06/29/2013 12:34 AM

Speak to the consultant and install 2x500kVA similar transformers suitable for paralleling. You can operate one at a time(weekly) and if load increases or if starting load is high put both in parallel.

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Users who posted comments:

gmanoj2020 (2); Joshi (3); pnaban (1); PWSlack (1); RAMConsult (1); silverfox (1); Snave (1)

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