25 kV.A for a permanent load; more if the load is variable.
with some of the very best transformers about 7kva with the ones made recently and costing 1/2 or 1/3 as much perhaps 25Kva
75 kV.A is the rated apparent power of the transformer which it can supply, continuously, to a load without overheating. When the transformer is not supplying a load, the primary current is (a) very small and, (b) lagging the supply voltage by practically 90 electrical degrees. Bear in mind that energy losses only occur for the component of current that is actually in phase with the supply voltage. So the energy consumed to the transformer is very small and is due to the resistance of the primary winding (copper loss) and a relatively small loss in the core (iron loss). Just how much energy this accounts for and, therefore, how much it costs to run the off-load transformer, is not possible to tell without knowing the full specification of the transformer.
It tells us how much is the transformer utilised in a given process. For a rectifier,TUF =(D.c.power delivered to the load)/(power rating of transformer secondary)
No because the load is 638 VA which is too much for the transformer.
If the load current is too high, the power lost in the transformer windings will be too high and it will overheat. If the voltage is excessive, the power lost in eddy currents in the magnetic core will be too high and it will overheat.
with some of the very best transformers about 7kva with the ones made recently and costing 1/2 or 1/3 as much perhaps 25Kva
You can bear a load.
75 kV.A is the rated apparent power of the transformer which it can supply, continuously, to a load without overheating. When the transformer is not supplying a load, the primary current is (a) very small and, (b) lagging the supply voltage by practically 90 electrical degrees. Bear in mind that energy losses only occur for the component of current that is actually in phase with the supply voltage. So the energy consumed to the transformer is very small and is due to the resistance of the primary winding (copper loss) and a relatively small loss in the core (iron loss). Just how much energy this accounts for and, therefore, how much it costs to run the off-load transformer, is not possible to tell without knowing the full specification of the transformer.
It depends on the load
It tells us how much is the transformer utilised in a given process. For a rectifier,TUF =(D.c.power delivered to the load)/(power rating of transformer secondary)
No because the load is 638 VA which is too much for the transformer.
The inductance of the transformer is much higher than the resistance of the transformer, resulting in very low real power losses (in watts), but some reactive power (vars).
Christ can bear any heavy load. Nothing is too much for Him.
If the load current is too high, the power lost in the transformer windings will be too high and it will overheat. If the voltage is excessive, the power lost in eddy currents in the magnetic core will be too high and it will overheat.
..the questions does not say wether the 30kVA transformer is 3 phase transformer or single phase transformer..but it is implying that a single phase welding load at 16A per phase is to be connect to it, it is assumed then that the transformer is 3 phase transformer..we assume load is rated 240V.. ..though not much details is given about the transformer voltage specs. but if is rated 3 phase 415/240V, the approx full load current per phase is given by 30KVAx1.3912=41.736A.. ..but if the transformer was rated single phase 240V say, the approx full load current FLC=30000/240V gives 125ampers.. ..if you further devide the FLC by the intended load current.. ..Recommended no of welders per for a 3 phase 415V transformer and assuming single welding sets =41.736/16=2.6..so you can connect max two welding sets to this transformer per phase,..max 6 weld sets can connect at an approx load factor of 76%.. ..for the single phase transformer, FLC/16=125/16, gives 7.8 but is also recommended not to connect more than 6 welding sets to such transformer for the same reasons..
A transformer has two coils coupled via the magnetic field, and when it has no load all you see is the inductance of the primary coil, which has to be fairly high to create the necessary amount of magnetic flux. When the transformer supplies a resistive load, the input looks much more resistive.
Fully loaded - 2.62 amps at 11kV. The no load depends on the transformer design, but it will usually be significantly less than the full load amps (not sure on this size, but on larger transformers it is typically ~.05 - .1% full load, so you'd be looking at ~2.5 mA RMS). The connection type is not important. Transformers are very efficient, thus there is not a whole lot of loss in the "average" transformer. The actual loss will depend on the design criteria of the transformer.