How to calculate transformer losses

Written by richard asmus
  • Share
  • Tweet
  • Share
  • Pin
  • Email
How to calculate transformer losses
Every transformer has loss. (transformer image by palms from Fotolia.com)

The loss in a transformer compares the input, or primary power, to the output, or secondary power. Most transformer data show their input and output voltages and the current ratings of both sides. A step-up transformer increases voltage, but decreases current. A step-down transformer decreases voltage but increases current. Power in watts (P) equals voltage (E) multiplied by current in amperes (I) or (P=IE). A transformer cannot increase power. To calculate the loss of a transformer you need to know the actual voltage and current in both the primary and secondary.

Skill level:
Moderately Easy

Other People Are Reading

Things you need

  • Pen or pencil and paper

Show MoreHide

Instructions

  1. 1

    Multiply the voltage in volts by the current in amps of the primary of the transformer. Record the figure.

    How to calculate transformer losses
    Transformer heat is power lost. (netzteil zerlegt image by pmphoto from Fotolia.com)
  2. 2

    Multiply the voltage in volts by the current in amps of the secondary of the transformer. Record the figure.

  3. 3

    Subtract the secondary power from the primary power. The answer equals your power loss. Example: the primary voltage of 440 volts with a current of 3 amps equals a power of 1320 watts. A secondary voltage of 220 volts with current at 5.7 amps equals a power of 1210 watts. Subtracting 1254 from 1320 equals 66 watts, which indicates that your transformer loses 66 watts, mostly in the heat it dissipates.

Tips and warnings

  • To calculate the transformer efficiency, divide the output power by the input power. Example: with an output power of 1254 watts for an input power of 1320 watts, divide 1254 by 1320, which equals .95, or an efficiency of 95 per cent.

Don't Miss

Filter:
  • All types
  • Articles
  • Slideshows
  • Videos
Sort:
  • Most relevant
  • Most popular
  • Most recent

No articles available

No slideshows available

No videos available

By using the eHow.co.uk site, you consent to the use of cookies. For more information, please see our Cookie policy.