An Electromagnetic Log, sometimes called an "EM Log", measures the speed of a vessel through water.
Contents
It operates on the principle that: 1 when a conductor (such as water) passes through an electromagnetic field, a voltage is created and 2 the amount of voltage created increases as the speed of the conductor increases.
The process is
- the EM Log creates an electromagnetic field.
- a voltage is induced in the water; the magnitude of the voltage varies depending upon the speed of the water flow past the sensor.
- the EM Log measures the voltage created and translates this into the vessel's speed through water.
Advantages
Disadvantages
References
Electromagnetic log Wikipedia(Text) CC BY-SA