MotorThe locked-rotor test is a key item for the inspection test and type test of the motor. What performance analysis indicators can be used to determine the motor's performance through the locked-rotor test research?Which manufacturing or design defects of the motor can be found in time?Let's take a look at the development together with the motor management staff:
Common methods of locked-rotor test:
The voltage value of the locked-rotor test can be selected according to the rated voltage of the motor. The locked-rotor current Ik and the locked-rotor loss TK are measured by the constant voltage method, and then the impedance Zd of the motor is calculated; the constant current method can also be used (according to the rated current equal to the locked-rotor Current) do an experiment, measure the locked-rotor voltage Uk, measure the locked-rotor current Ik and the locked-rotor loss Pk, and then calculate the motor impedance Zd.The motor is an electromagnetic device that realizes the conversion or transmission of electric energy according to the law of electromagnetic induction.Frequency conversion speed motorA general term for motors driven by frequency converters.In fact, the motor designed for the frequency converter is a special frequency conversion motor. The motor can achieve different speeds and torques under the drive of the frequency converter to adapt to the changes in the demand of the load.Explosion-proof motorsA type of motor that can be used in flammable and explosive plants, and it does not generate sparks during operation.Explosion-proof motors are mainly used in coal mines, oil and gas, petrochemical and chemical industries.In addition, it is also widely used in sectors such as textiles, metallurgy, city gas, transportation, grain and oil processing, papermaking, and medicine.
When the constant current method is used to block the rotor, the rotor should be blocked and cannot rotate (for wound rotor motors, the rotor should also be short-circuited), the stator winding is energized, and the voltage is adjusted by the voltage regulator to gradually increase the voltage from zero. When the current of the energy-saving motor reaches the rated current ik, stop boosting and measure the values of voltage uk and ik.
At the time, you can use the method of no three-phase power supply, single-phase power supply, this time there is no brake rotor, which simplifies the operation test procedure (not recommended).When the three-phase power method is used to block the motor shaft, the rotor does not move.It should be reminded that, for testing, the power meter uses a low power factor meter.
During the inspection, the locked-rotor test research can evaluate the welding quality of the motor windings, check whether the stator and rotor reactance is normal, check whether the cage rotor is broken, and increase the number of rotor poles used by the students. (This is a problem that is very easy to analyze and find in the locked-rotor test).
