EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: Gurumurthy on June 13, 2017, 04:02:43 pm
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Dear all,
I bought a step down transformer, its rating at primary is 230V and secondary side 6V-0-6V @ 5 Ampere(centre tap transformer).What is VA rating Available at secondary side of the center tap Transformer before Rectification?
what i Suspect is each Line of the secondary winding will give 6V*5A=30Watts. hence i could get totally 60 Watts from both lines with respect to center tapping. but if taken with respect to both lines of the secondary side it would give 12V*5A=60Watts. is This correct????
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Correct.
But remember VA (volt-amps) only equals Watts at unity power factor.
That includes both angle displacement and distortion factors.
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Correct.
But remember VA (volt-amps) only equals Watts at unity power factor.
That includes both angle displacement and distortion factors.
The DC have only one power that is the familiar Watt which is a resistive power, but the alternating current does have two more power types the VA (Volt-amperes) and var (Volt-Ampere reactive ). The VAr (or var) indicates the as said reactive power, which is formed from the relation of the capacitance and inductance (caps and coils) in the "network", the trap is that the coil and caps can cancel each others out (the VAr can be zero, while there is both caps and coils in the circuit/network). The Watts as W is "passive" power, also resistive power term is used, it is the pure resistor load in the circuit. The Volt-Amperes is the compination of these two Watts and VArs.
This is simplified description as these are calculated in complex domain (but most of the time can calculated with simple sin, cos, tan and pythagoran theorem without knowledge of complex calculus).
https://en.wikipedia.org/wiki/Volt-ampere_reactive