What is core loss test?
Core loss testing provides a quick and efficient method for determining core losses found in the core steel of stators, rotors, and armatures. Core Loss testing is one of the most important quality assurance tools in the motor repair industry and is virtually a requirement when rewinding a motor.
What is stator core buckling?
Buckling Phenomenon – “buckling phenomenon”, which is a circumferential “wave” shape of the core laminations that can occur when the stator frame constrains thermal expansion of the stator core. Building Bolts – Part of the core clamping system.
Which material is used for stator core?
silicon steel plate
The stator core uses an isolated thin silicon steel plate that consists of oxide and varnish. Therefore, the hysteresis loss and eddy current loss in the inner magnetic material can be minimized.
What is core loss in motor?
Core loss in magnetic material is a measure of the heat generated within the material as a result of the alternating current. High core losses result in poor electric motor thermal efficiency. An inefficient magnetic part can drag down an entire AC electric motor design.
What is used lamination for the stator?
D. Explanation: the stator is made up of a block of laminations. the block of laminations are made up of cast iron or die cast aluminium alloy frame.
Why do we perform no load test?
This test gives the information regarding no-load losses such as core loss, friction loss and windage loss. Rotor copper loss at no load is very less that its value is negligible. Small current is required to produce adequate torque. This test is also well-known as running light test.
What is the function of stator core?
The primary functions of a stator core are: (1) to hold the stator windings in place, and (2) to transmit flux. A stator core in a large AC machine is constructed from thin laminated sheets of electrical grade steel such as ASTM A 345.
What happens if motor runs without load?
In case of electric motors, running on no load does not have any effect on the motor, other than a little bit of wear. It is no problem at all for the motor. For a combustion engine, no load might be a bigger problem.
Why blocked rotor test is done?
The blocked rotor test enables us to determine the efficiency and the circuit parameters of the equivalent circuit of a 3-phase induction motor. In the blocked rotor test, the shaft of the motor is locked so that it cannot rotate and the rotor winding is short circuited.
What causes core losses?
There are two main causes for the core losses: ohmic or Joule heating generated by the eddy currents, induced in the conductive media by the alternating magnetic field, and the losses caused in the ferromagnetic materials by the cyclic reversal of the magnetization and proportional to the area of the hysteresis loop.
What is stator loss?
These losses occur due to current flowing in stator and rotor windings. As the load changes, the current flowing in rotor and stator winding also changes and hence these losses also changes. Therefore these losses are called variable losses.
What is the stator core induction test?
STATOR CORE INDUCTION TEST General: The core induction test is a test technique in order to find hot spots in/at the stator cores of rotating machines; reasons for such hot-spots are local damages of the lamination. Introduction During the service-time of rotating machines it may become necessary to check…
What is core flux loop test?
Core flux “Loop” test is the standard test utilized for evaluating the insulation integrity of laminated stator cores. The test establishes a specific magnetizing level for the core by energizing the loop coil with single phase power.
What is the best way to test stators?
Two extremely useful testing technologies used for quality control of stator repairs are Loop tests (Ring Flux tests) with Thermography and Electromagnetic Core Imperfection Detector or ELCID. Both have their advantages and also their limitations and thus compliment each other perfectly.
What is a stator made of?
The stator is made up essentially of windings and an iron core. An iron core can develop core losses because of winding failure, aging and deterioration due to heat. Iron cores are made of thin laminated steel sheets.