Trigonometry on a transformer

[johann1301]

On a trafo i just bought, it says COS Ø = 0,99. What does this mean?
Is there some angle involved in changing the voltage?

 

[PhysicoRaj]

That is the 'Power factor'. To be simple, the ratio of actual power consumed to the product of voltage and current through the trafo is 0.99, it means.
See this:
http://en.wikipedia.org/wiki/Power_factor

 

[PhysicoRaj]

Here's a simpler version:http://www.tvss.net/pq/pf.htm

 

[jim hardy]

trafo ?

http://www.trafo.co.in/To your trig question:

cos^-1(0.99) = 8.1 degrees
and that's the angle between primary side volts and amps at rated resistive load.


draw a right triangle with a hypotenuse of 1, base of 0.99 and an opposite side of 0.1424
this represents primary current at rated conditions with resistive load
small angle is 8.1 degrees
base is 0.99 units and is load current corrected for turns ratio
opposite side is 0.1424 units and is magnetizing current
hypotenuse is total current flowing into primary

so this transformer draws 14.24% magnetizing current.

 

[alphy]

Trigonometry is a branch of mathematics that deals with the relationships between the sides and angles of triangles. In the context of a transformer, the term "COS Ø = 0,99" likely refers to the power factor, which is the cosine of the phase angle between the voltage and current in the transformer. A power factor of 0,99 indicates that the voltage and current are almost perfectly aligned, which means that there is minimal loss of energy in the transformer. This is important because transformers are used to change the voltage of an electrical current, and any loss of energy can result in inefficiency and potential damage to the transformer. Therefore, a high power factor is desirable in a transformer. In short, the angle involved in changing the voltage is the phase angle, and a power factor of 0,99 indicates a near-perfect alignment between voltage and current.