Previous in Forum: Transformer winding specs for 220/12 V   Next in Forum: vector group
Close
Close
Close
8 comments
Rate Comments: Nested
Associate

Join Date: Aug 2007
Posts: 25

Technical evaluation of transformers

04/05/2008 11:05 PM

I appreciate if somebody can guide the parameters to be looked in while carrying out technical evaluation for selection of a suitable tranformer for specs given in the enquiry.

Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

"Almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, vote them!
Active Contributor

Join Date: Mar 2008
Location: India
Posts: 12
#1

Re: Technical evaluation of transformers

04/07/2008 2:43 AM

You can evalute the transformer from the various manufacturer with following parameters:

1. Transformer Losses

2. Auxiliary Power Consumption

3. Transformer Efficiency at various loads.

4. Transformer Regulation.

5. No. of Cooling units provided.

6. Percentage Impedence (if not specified in the specification)

7. Winding and Top Oil temperature

I thought above perameter are well enough for evalution of transformer.

for forther query please inform.

Register to Reply
Associate

Join Date: Aug 2007
Posts: 25
#5
In reply to #1

Re: Technical evaluation of transformers

04/08/2008 12:25 PM

Thanks for prompt response and shall use the points given.

Register to Reply
Power-User

Join Date: Dec 2007
Location: Chicago, IL, USSA
Posts: 141
Good Answers: 3
#2

Re: Technical evaluation of transformers

04/07/2008 11:57 AM

Hi VASU,

Are you looking to size a transformer for a load, or actually quality test a transformer? If you are sizing to a load here are the basics you need to know.

1) 1PH or 3PH

2) Voltage needed on the Primary side (source voltage available)

3) Voltages needed on the Secondary side (load voltages)

4) Maximum current the load will pull, if it is an inductive(motor load) then what is the Inrush current at start up of the motor - if you don't know take nominal current and double it so the transformer will only be loaded 50%) . A general rule of thumb is 60-70% loading for transformers.

Register to Reply
Associate

Join Date: Aug 2007
Posts: 25
#6
In reply to #2

Re: Technical evaluation of transformers

04/08/2008 12:28 PM

Thanks for your prompt response but we need points for technical evaluation based on the tech.specs in the tender.

Register to Reply
Power-User

Join Date: Oct 2006
Location: Indonesia
Posts: 102
#3

Re: Technical evaluation of transformers

04/07/2008 11:04 PM
TypeOutdoor, mineral oil immersed, hermetically sealed
Rated power

------- kVA.

Overload requirements------- per unit for 1 hour
No load ratio------/------ VAC
Frequency-- Hz
Highest voltage of equipment – primary-- kV
Highest voltage of equipment – secondary--- V
Insulation levels – primary--- kV peak (impulse)

--- kV rms (power frequency)

Insulation levels – secondary--- kV rms (power frequency)
Impedance Voltage at rated power nominal tap--- % (nominal)
System earthing (HV)Solidly Earthed
System earthing (LV neutral)Solidly Earthed
Winding MaterialCopper
Connection vector symbolDyn11
Type of coolingONAN
Temperature rise limitsTop oil 55°C, average winding 60°C
Insulation Temperature ClassF
Winding insulation categoryUniform
Max. mean sound pressure level on 100% load60 dB(A) at 1m
Tappings (off circuit lockable)± 2.5%, ± 5%
Register to Reply Score 1 for Good Answer
Associate

Join Date: Aug 2007
Posts: 25
#7
In reply to #3

Re: Technical evaluation of transformers

04/08/2008 12:31 PM

Thanks for your prompt response but we require points for technical evaluation.

Register to Reply
Power-User

Join Date: Oct 2006
Location: Kolkata, India
Posts: 447
#8
In reply to #3

Re: Technical evaluation of transformers

04/10/2008 6:54 AM

The data sheet is generally ok. But need to include many more. Add Transformer losses as a vital information, this is required to braing costa of different bid at PAR.

__________________
BNDas
Register to Reply
Active Contributor

Join Date: Mar 2008
Location: India
Posts: 12
#4

Re: Technical evaluation of transformers

04/07/2008 11:19 PM

Dear Vasu,

You are asking for Technical Evalution of Transformers. It means you have technical specification of transformer with you. First of all ensure all parameters proposed by the vendors are matching with the technical specification. For further evalution you may considered parameter as mentioned earlier.

If you are still have any query please let us know.

Regards

Manish Ahuja

Register to Reply
Register to Reply 8 comments

"Almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, vote them!
Copy to Clipboard

Users who posted comments:

Abu Khansa (1); ahuja4 (2); Apps Man (1); biswanath.das (1); vasu (3)

Previous in Forum: Transformer winding specs for 220/12 V   Next in Forum: vector group

Advertisement