Sunday, 12 January 2020

Core Loss Test




Core Loss Test





The main source of  energy loss in motor is due to the losses produce in motor during running condition. These losses includes stator copper loss (I²R), Stray load loss, windage loss, friction loss and loss in rotor, stator or armature core. The core loss test is performed to determine the loss in stator core or armature core. These core losses are divided into hysteresis loss & eddy current loss. To increase of theses loss result is physically damage or over heating the core .Due to overheating winding in the stator core is burnt out or winding insulation failure. Core loss is dissipated in the form of heat & it further degraded the core ,causing greater core loss and more heat. This will increase the machine temperature & it will affect the motor efficiency. Core loop (Flux) test is standard test utilized for evaluating insulation integrity for lamination of stator core. The test is establishes a specific magnetizing level for core by energizing the loop coil with single phase power. Any defective areas of core or core slot or core tooth insulation shows up Hot Spot in that they will become significantly hotter than surrounding other normal areas. Give the single phase supply to core as per shown in figure & measure the temperature of core at particular time interval (up to 30 minute). The final hot spot temperature difference is not more than 15C acceptable. If the difference of hot spot is more than 15C [ Note : Some standards ( IEEE 1068 ) require to be within 10C like fan standard efficiency motors.]  then rework of stator core is needed & after rework repeat the test until acceptance criteria met. If same observation is repeated then new stator core lamination is required.


 


3 comments:

  1. Really help u r blog for industrial used.....Thank for writing & sharing such information .....keep writing bro.....best of luck for your next blog��

    ReplyDelete
  2. Can it is useful for small motor?

    ReplyDelete

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