No load current is energizing current. This is effectively "lost" power, power used in the transformer to energize the core. It, therefore, should be small!
When the secondary of a transformer is opened, there is no longer any load on the transformer. There will be some current flowing in the primary winding, which is needed to induce the voltage in the secondary. This primary current is referred to as the "no load" current, and is indicative of the core losses in the transformer.
No load current depends on the design of the transformer, and what voltage it is energized at. It will typically be below 1% of full load, and can be significantly below 1% for utility sized transformers.
The current flowing in the primary generates a magnetic field which induces a current in the secondary winding.AnswerNo current is induced into the secondary winding of a transformer. What is induced is voltage. Current will only flow in the secondary winding if it is connected to the load, and it is the load that determines the current, not the primary current.
The no-load current of a transformer is the current which is drawn from the source at rated voltage and frequency even when no actual load current is being supplied.The no-load current is what must be drawn to overcome the inherent and unavoidable losses of the transformer's components. Those losses comprise the primary circuit's resistance (known either as the "copper losses" or as the "resistance losses") and the transformer's magnetic reluctance (known either as the "iron losses" or as the "magnetic losses").Reluctance is the techical description given to the energy necessary to excite the magnetic circuit and overcome its hysteresis, the effects of eddy currents, etc.For more information see the Related link shown below.
The secondary current is determined by the load, not by the transformer. But the load current mustn't continuously exceed the rated current of the secondary winding. To determine the secondary rated current, you need to know the rated secondary voltage of the transformer, and divide 315 kV.A by this figure.Incidentally, the correct symbol for 'kilovolt ampere' is 'kV.A', not 'kva'.
load
It is a transformer with No load attach to it.
2 to 5% of full load current
I am assuming the question is about the power / distribution transformer and not the current transformer. The primary current is a function of load connected on secondary. With the open secondary, there is no load, no current, it is open circuit. Hence no primary current. However there is always some small amount of no load current in the primary winding.
is it primary current ?
To calculate the no load current from transformer & core loss is also calculated.
No load current, in a transformer for example, is the current necessary for exciting the transformer. If you wish to keep it energized, and you need to keep it energized at full voltage, there is nothing you can do to reduce this other than replace the transformer with one that has lower no load current. If you are referring to a different piece of equipment, you may need to specify what you are meaning by "no load current".
When the secondary of a transformer is opened, there is no longer any load on the transformer. There will be some current flowing in the primary winding, which is needed to induce the voltage in the secondary. This primary current is referred to as the "no load" current, and is indicative of the core losses in the transformer.
major component of power loss in a transformer is secondary resistance.when transformer is operated under no load,no current flows through the secondary.so under no load conditions transformer has just very small megnetic losses.
When the value of the load resistance in a transformer is changed, it will affect the current flowing through the circuit. Increasing the load resistance will decrease the current, while decreasing the load resistance will increase the current. This change in current will in turn affect the voltage across the load and the efficiency of the transformer.
No load current depends on the design of the transformer, and what voltage it is energized at. It will typically be below 1% of full load, and can be significantly below 1% for utility sized transformers.
The secondary current is determined by the load, not by the transformer. For example, if the secondary voltage is 50 V and the load is 100 ohms, then the secondary current will be 0.5 A. If the load is 25 ohms, then the secondary current will be 2 A. It is important that a continuous secondary current doesn't exceed the rated secondary current of the transformer.