Find the wire from the secondary of the transformer. If it's a step-down transformer the thicker wire is the secondary.
Measure its diameter in inches and calculate its cross-section area in square inches. The current rating for transformer wire is 1000 amps per square inch, or 1.55 amps per square mm.
Any continuous load shouldn't exceed the rated capacity of the transformer, expressed in volt amperes.
For a single-phase transformer, divide the ratedapparent power (expressed in volt amperes) by the voltage rating (expressed in volts) of the primary winding; this will give you the rated primary current (expressed in amperes) of the primary winding.
The correct symbol for kilovolt amperes is 'kV.A, not kva. A volt ampere is the product of the transformer's secondary rated voltage and its rated current. It is not rated in watts, because the transformer designer has no idea what sort of load is to be applied to the transformer, and it is the load that determines the amount of watts, not the transformer.
What limits the use of a transformer is its operating temperature, as excessively-high temperature will act to break down its insulation. The temperature reached by a transformer is a function of its rating (expressed in volt amperes), so operating a transformer below its rating is perfectly okay.
the capacity of a transformer is defined as a product of voltage and current flowing through it.AS THE CURRENT IS MEASURED IN AMPERES AND VOLTAGE IN VOLTS, Hence transformers are measured/rated in KVA
It enables an existing transformer to be upgraded to meet an increase in load, without having to remove that transformer and replace it with a 'larger' (expressed in volt amperes) one. It provides an useful way of using up a stock of smaller transformers.
You need to use a 2:1 ratio transformer, with a capacity (in volt amperes) to match the load you have in mind.
To calculate the no load current from transformer & core loss is also calculated.
ka of mccb=transformer(KVA)x100/1.732xsecondary voltagex%impedence of transformer
Transformers are rated in KVA. (this is because the transformer is Unity power factor device i.e.. PF = 1)AnswerThe selection of a transformer is determined by the apparent power of the load, expressed in volt amperes(V.A), the load current, and the line voltage of the supply. The transformer must be able to satisfy these requirements.Transformers are not 'unity power factor' devices, which is precisely why their capacity is expressed in volt amperes, rather than in watts.
Apparent power is the product of voltage and current in an a.c. system, and is expressed in volt amperes. The rated apparent power of a transformer is the product of its rated secondary current and rated secondary voltage.
First of all, transformers are rated in volt amperes, not watts. Secondly, in order to determine a transformer's turns-ration, you need to know its primary and secondary voltage ratings.