Transformer impedance
Transformer impedance
(OP)
We received information about newly planned transformer parameters. It states: "Transformer... with a nominal 5.75% impedance. The impedance per ANSI C57.12.51 is to be within 7.5% of nominal". I haven't seen this standard, but I assume that 7.5% is not another value of impedance but rather manufacturing tolerance on the value of nominal (or design) impedance. So, I might have a transformer with real impedance of (5.75 +/-0.075)%. Is that true?






RE: Transformer impedance
RE: Transformer impedance
RE: Transformer impedance
Short circuit calc. is commonly do before the transformer is build. Therefore, it is good practice to reduce the specify impedance in 7.5% to obtain the worse case with the larger SC current.
RE: Transformer impedance
Most transformers are specified with options to increase the capacity by as much as 40% above the nominal capacity.
RE: Transformer impedance
Spec are done at a "nominal temperature,and connection
resistance, as well as load current, input volts, ect".
All must be understood, to make a good evaluation.
RE: Transformer impedance
Could you please elaborate more about the meaning of "nominal temperature,and connection resistance, as well as load current, input volts, ect".
RE: Transformer impedance
To me nominal means "the expected limited conditions
for operation, as well as the expected results from
other conditions".
In this case the spec is 7.5% and was recived a 5.75%
item.
The point I was trying to make, Is if the operating
conditions are the same then a better unit was supplied.
If the operating conditions are not (anything is different),
than all conditions should be evaluated to ensure that the
"entire required specs are met".
I have under mil specs, been sent laminatins that
did not meet the specs. Mil spec requires a cert with
every shipment. It took 6 mo to resolve.
Well the material was not realy M6 is not an answer.
Get the point.