In the electrical machine various types of reasons occurs of power losses and its losses affected on the machines and decrease that efficiency so it causes of loss of electricity..
The following are the power losses (Loss of electricity) given the bellow..
loss of electricity
Copper or Electrical Losses :
- These losses occur in the rotor and stator (armature and field) winding.
- In synchronous and d.c. shunt machines (except where variable speed is obtained by control of shunt field current), the field copper loss is constant because such machines are normally operated with constant field current.
- series and induction machine in the losses in both windings vary as the square of the line current.
Core or Iron Losses :
- These losses consist of eddy-current and hysteresis losses.
- In synchronous and induction machines, these losses are confined essentially to the stator iron and in d.c. machines essentially to the rotor (or armature) iron, although in both cases a small core loss will be present in the other member because of small flux variations caused by the slots.
- The iron in the defacing member is laminated to reduce the eddy- current losses. In all except series machines, variable-speed shunt motors, and to a lesser degree, compound motors, the air-gap flux and hence the core losses are sensibly constant regardless of load.
3. Friction and Windage Losses :
- These losses are constant until the speed varies appreciably. The sum of the friction and windage with core losses in called the rotational losses.This losses will not be occur in the transformer .
4. Stray-Load Losses :
- These are additional hysteresis and eddy-current losses arising from any distortion in flux distribution caused by the load currents.
- These losses are difficult to measure and are usually about 1% of the machine output.
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