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  • Users: petronila
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  1. petronila

    How many hp or kW

    Dear All Please see attached picture. No data for hp or amps only volts, frequency and LRA any idea of the power rating? Thanks Petronila https://files.engineering.com/getfile.aspx?folder=0c8c55a3-c8a2-4f90-97d2-52a1d5af9f9c&file=York.jpg
  2. petronila

    Flexible damper winding jumpers

    Dear All, I have seen some OEM use flexible jumpers for connecting the damper winding of the synchronous motors/generators (see attached pictures). I would like to know your inputs of what should be the justification for such design. Thanks in advance Petronila...
  3. petronila

    DC Motor leads Chart

    Dear All, Looking for a lead chart for DC motors based on Amp and temperature rating. Thanks in advance Petronila
  4. petronila

    Thermal protection devices fror stator windings

    Dear All, I would like to receive your inputs about how calculate/select this types of devices (thermistors, RTDs,thermocouples, etc.) based on insulation class of the stator windings. Thanks and Regards Petronila
  5. petronila

    P.A.M Winding Diagram 6 & 10 pole 90 Slots

    Dear All, I am looking for a 6 & 10 pole P.A.M Internal Connection Diagram. 90 Slots Thanks Petronila
  6. petronila

    Lead Chart for DC Machines

    Dear all, Some lead manufacturers provide tables with the ampacity chart for electric motors that have been used mainly for AC machines but what about DC Machines? Does someone can share an ampacity chart showing the led size for DC Machines? Thanks Petronila
  7. petronila

    Formula for determining the output power in a electric motor shaf

    Dear all, Does anybody have the formula to correlate the shaft dimensions (diameter and length) with the rated output (kW/hp) in one electric motor? Thanks in advance Petronila
  8. petronila

    Gearbox in EX Proof Area

    Dear All, If you have an ATEX (EX Proof)motor attached to a gear box does the gear box should be ATEX (EX)certified too? The gearbox is a non-electrical equipment thus how should be chossen? Thanks and Regards Petronila
  9. petronila

    Lubrication Intervals for Bearings

    Dear All, The attached file is a graph used for lubrication intervals for bearings of electric motors, did someone recognize the source of the graph? If so can share the original document, if possible. Thanks in advance...
  10. petronila

    VFD starting several motors

    Dear All, I would like to know your pros and cons for using only one VFD for starting several motors. The application had four 350 hp 8 pole 3-phase motors involved and once the VFD starts the first motor then the second one is started using the VFD and so on. The problem here is some of these...
  11. petronila

    skewed slots in AC generator´s stator

    Dear all, It is well known the skewed rotor bars in induction motors are used for avoiding CUSP, cogging and noise in three-phase induction motors. However, there is also the possibility of skewed slots in the stator. One of my collegues came to me looking for explantions of skewd slots in a...
  12. petronila

    Efficiency loss associated with a HIGH or DRASTIC reduction in CM/A.

    Happy Holidays, There are some cases when the redesign of a winding from concentric to lap, specially in 2 pole machines, results in a HIGH or DRASTIC reduction in the wire area per turn and sometimes the reduction may range from 5 % to 7 % or above. My question is if there is a formula or...
  13. petronila

    460/575 connection

    Dear All, Sometimes we find some motors rated 460/575 v connected in Delta for 460 V and connected with a combined wye-delta connection for 575 V rated for the same hp at the same speed at both voltages(i.e. 100 hp 4 poles 460/575 v 60 Hz). See attached. Thoughts why the manufacturer rated...
  14. petronila

    Testing damper winding in a salient pole rotor

    Dear All, I am looking for a reliable test method/procedure for testing the damper windings in a salient pole rotor. See attached sketch. The idea is to test the condition of the bars (detecting cracked or damaged bars or any abnormal condition of the whole damper winding) without dismantling...
  15. petronila

    2 pole winding with "12 groups"

    Dear All, There are some OEM that designs 2 pole motor using 12 groups rather than 6 groups and connecting in series one group with the inmediatelly adjacent group forming a group with the double of coils, (i.e. 2 pole-36 slots with 12 groups of 3 coils pitch 1-14,16,18). Can somebody share a...
  16. petronila

    Oil for submersible pumps

    Dear All As you know, there are submersible pumps with the winding cavity filled with oil. This oil should be obviously dielectric oil. However, the main concern here is the oil should be compatible with the insulation system of the winding. Usually the oil is refined paraffinic type. Does...
  17. petronila

    Star Ring Sizing

    Dear All Usually, in large motors that are internally connected in parallel stars (3Y-4Y-5Y-6Y, etc.) we found all stars connected with a star ring. When repairing, make sense to use the same wire/conductor size that we found in the original winding, but there are some cases where repair shops...
  18. petronila

    Rectangular Magnet Wire For 4.16 kV Motors VFD Driven

    Dear all SCIM is powered with VFD and but Inverter Duty rectangular wire is not available for rewinding. Winding was not stripped yet so I can´t calculate the volts/turn but due to the stator winding will be subjected to very high temperatures and dv/dt´s I doubt mica over film will works...
  19. petronila

    EBKL and EBRL meaning in bearing designations

    Dear All First of all I want to wish you a Happy Holidays I found a name plate with bearing information in a nameplate Motor manufacturer is using the terminology DE Bearing: EBKL 6304 C3/---- and NDE Bearing: EBRL NU ... Did you know the meaning of EBKL and EBRL? Thanks Petronila
  20. petronila

    Converting random winding to form winding

    Does anyone have technical information for converting a random winding to form winding? Thanks Petronila

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