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  1. Leendabests

    Overheated sign on stator coil

    The motor is failed due to damage bearing. Thus, it has melted the rotor around bearing and broke it down. Then we check the insulation resistance and we got 2-3 GigaOhm for all 3 phases. Hipot test has been done using Baker Winding tester. Result as attached. We found out there is overheated...
  2. Leendabests

    Overheated sign on stator coil

    Hi, I would like to get an advise and opinion regarding to the overheated coil in the induction motor. Recently I have dissemble 1 unit 315 KW Induction motor . We found out that the rotor has marked such as the color of metal at the rotor turned to rainbow color. It is sign of the motor is...
  3. Leendabests

    Switched Reluctance Motor Inductance Test

    According to R.Krishnan,‘‘Switched Reluctance Motor Drives, Modeling, Simulation, Analysis, Design, and Applications’’. The range of the ratio between unaligned and aligned inductance should be 0.07 < Lmin/Lmax < 0.18 which Lmin is unaligned and Lmax is aligned rotor. Can it be used as...
  4. Leendabests

    Switched Reluctance Motor Inductance Test

    The test has been made on assembled motor. We just rotate the rotor and take the inductance reading without knowing the rotor position.
  5. Leendabests

    Switched Reluctance Motor Inductance Test

    Dear All, I have done an inductance and winding resistance test for 75 KW SRM Motor. How could I determine whether the motor is in good condition or not based on the Inductance test result. The test has been done offline. 1) Inductance test at 100 HZ using LCR Meter : A1-A2 @ 100Hz Lmin = 0.93...
  6. Leendabests

    Electric motor insulation drop after cleaning

    Hi guys, I would like to share one of the insulation drop cases. For this case we have done hipot test using Baker Digital Winding Tester. The result as attached. The insulation has increased but there is EAR(error area ratio)which is impulse test has reached more than 100%...
  7. Leendabests

    Electric motor insulation drop after cleaning

    Dear Team, I have experienced several problem regarding to the compressor motor. Our client have sent the compressor motors range between 250 HP to 450 HP. We are following standard service step by step. After dissemble the motor, we have done IR test at each phase of coil to check the healthy...
  8. Leendabests

    DC Motor heavy sparking

    Brush position checked and adjusted. No sparking free load. When motor getting full load, the commutator sparking and motor tripped. It is related to drive problem?
  9. Leendabests

    DC Motor heavy sparking

    Dear friends, Currently i am facing a problem With DC Motor.problem is mentioned below: 1. DC motor was overhauled.Rewound Field Interpole and armature windings.all windings are in good condition with 2000 Mohms value. 2.Polished and skimmed the commutator,,drop tested. found ok. 3.Brush and...
  10. Leendabests

    DC Motor cant turn

    We have checked all the current and voltage free load, made measurement on winding resistance and insulation resistance. No abnormal value detected. The motor is 125 KW using as DC motor controller for the printing machine. The motor got excessive vibrate and high amp on load. Other motor has...
  11. Leendabests

    DC Motor cant turn

    Hi friends, Im facing problem with DC motor at our factory which is cant turn on load or rotate very slow. We have checked all the insulation at Field coil and armature coil and they are all having good IR which is Field coil(2000 Megaohm), Armature coil(2000 MegaOhm). Carbon brush just changed...
  12. Leendabests

    Electric Motor using at escalator overspeed

    The motor is directly powered from supply. No vdf connected to the motor.
  13. Leendabests

    Electric Motor using at escalator overspeed

    What cause to the motor slip more than 10%? Is it related to the electromagnetic, impedance, resistance, torque? The slipped happen once in awhile not everytime its running.
  14. Leendabests

    Electric Motor using at escalator overspeed

    The escalator will trip if it is overload. The overspeed.. is it related to slip frequency? what causes the slip frequency can occur?
  15. Leendabests

    Squirrel Cage Rotor Testing

    Hi... We having same issues as your. But the test we have made it induced the current into the rotor to heat and then scan using infrared to detect hot spot more than other part of rotor. It is not really practical because surface of the rotor also can produce hot spot. Rotor is one of the...
  16. Leendabests

    Electric Motor using at escalator overspeed

    Yes... when there are load of people at the slipped escalator but not overloaded... there are 2 escalators side by side.. the other one working in good condition with the same capacity as the slipped one. They are using Ac motor coupled with gearbox. It happen once in a while but still danger to...
  17. Leendabests

    Electric Motor using at escalator overspeed

    Dear All, I have one case where there is an escalator speed up while going down when loads of people on the escalator. The electric motor that has been used is 4 pole. My question, how the motor can ran overrated rpm? The motor still in the good condition. Thank you. Hope to hear from you...
  18. Leendabests

    DC Motor Failed to run on load

    The problem solved! The armature has been rewound and it successfully run. Thank you for all supported.[thumbsup2]
  19. Leendabests

    DC Motor Failed to run on load

    SOrry for the mistake.. The old tach is 20V/ 1000 RPM and the new tach is 20V/7200 RPM (max)... The rated voltage is 453 V 3000 RPM.. We have made some test to the tach, we have made free load test for old tach.... It is ran 57 V for 3000 RPM and for new tach 61 V for 3000 RPM....
  20. Leendabests

    DC Motor Failed to run on load

    We have made surge test and winding test to the field coil. Phase to phase coil showed balance. We got the rated voltage and ampere. Still facing the same problem.. I have doubt here.. Will it possibly cause from tachometer? We have change the new tachometer from 20 A 1000 RPM to 20A 7200...

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