Register to reply

Trigonometry on a transformer

by johann1301
Tags: transformer, trigonometry
Share this thread:
Apr22-14, 05:48 AM
P: 175
On a trafo i just bought, it says COS = 0,99. What does this mean?
Is there some angle involved in changing the voltage?
Phys.Org News Partner Engineering news on
DIY glove-based tutor indicates muscle-memory potential
Tricorder XPRIZE: 10 teams advance in global competition to develop consumer-focused diagnostic device
Study shows local seismic isolation and damping methods provide optimal protection for essential computing equipment
Apr22-14, 06:00 AM
PF Gold
PhysicoRaj's Avatar
P: 437
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:
Apr22-14, 06:02 AM
PF Gold
PhysicoRaj's Avatar
P: 437
Here's a simpler version:

jim hardy
Apr22-14, 09:49 AM
Sci Advisor
PF Gold
jim hardy's Avatar
P: 3,679
Trigonometry on a transformer

trafo ?

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.

Register to reply

Related Discussions
Trigonometry problem help Precalculus Mathematics Homework 0
Solving trigonometric equation Precalculus Mathematics Homework 2
Is Aluminum-Aluminum wound transformer better than Copper-Copper Transformer? Electrical Engineering 13
Prove cosign problem Precalculus Mathematics Homework 5
C3 Trigonometry help Calculus & Beyond Homework 1