Service Information WEG Motor Bearing Inspection Procedure File In/With: – Equipment Affected: YK and YD New SI0417 Product Technical Support GENERAL The purpose of this Service Information Letter is to identify potential motor bearing accelerated wear and to contain or reduce the risk of premature bearing failure. This inspection procedure was developed to acquire adequate and consistent information on motors currently in operation. Bearing symptoms include - darkened grease (Mobil Polyrex EM is normally Blue in color), elevated vibration, temperature or unusual sounds. SITE INSPECTION 1. Upon arrival to the site the Micro panel history should be reviewed, and any histories that are related to bearing temperature or vibration should be downloaded for factory review. 2. Vibration testing should be recorded when possible and micro panel trending or preferably Data Logging of the system operation at the same time as the vibration information is collected. Data sampling should be at 5 seconds during the vibration testing. 3. Determine if re-grease maintenance was performed as specified in the micro panel re-grease schedule. 4. If the chiller is operating check for elevated bearing temperatures (150°F or 65°C is high end of normal), vibra- tion or unusual sounds. 5. If the chiller is not operating the NDE (non-drive end) bearing cover should be removed to inspect the grease color and bearing cage integrity. 6. The grease in the bearing or cap should be removed for a sample, the lab will require a teaspoon of grease per test. If looking at wear, you would want to make sure the sample collected is relative to the contact areas and sent for testing to the lab of your choice. NOTE: If under factory warranty contact PTS for WEG preferred lab address. 7. The motor to the compressor alignment should be verified. Work on this equipment should only be done by properly trained personnel who are qualified to work on this type of equipment. Failure to comply with this requirement could expose the worker, the equipment and the building and its inhabitants to the risk of injury or property damage. The instructions on this service information letter are written assuming the individual who will perform this work is a fully trained HVAC & R journeyman or equivalent, certified in refrigerant handling and recovery techniques, and knowledgeable with regard to electrical lock out/tag out procedures. The individual performing this work should be aware of and comply with all Johnson Controls, national, state and local safety and environmental regulations while carrying out this work. Before attempting to work on any equipment, the individual should be thoroughly familiar with the equipment by reading and understanding the associated service literature applicable to the equipment. If you do not have this literature, you may obtain it by contacting a Johnson Controls Service Office. Should there be any question concerning any aspect of the tasks outlined in this bulletin, please consult a Johnson Controls Service Office prior to attempting the work. Please be aware that this information may be time sensitive and that Johnson Controls reserves the right to revise this information at any time. Be certain you are working with the latest information. 1019
Transcript
ServiceInformation WEG Motor Bearing Inspection Procedure
File In/With: –
Equipment Affected:
YK and YD
NewSI0417
Product Technical Support
GENERALThe purpose of this Service Information Letter is to identify potential motor bearing accelerated wear and to contain or reduce the risk of premature bearing failure. This inspection procedure was developed to acquire adequate and consistent information on motors currently in operation.
Bearing symptoms include - darkened grease (Mobil Polyrex EM is normally Blue in color), elevated vibration, temperature or unusual sounds.
SITE INSPECTION1. Upon arrival to the site the Micro panel history should be reviewed, and any histories that are related to bearing
temperature or vibration should be downloaded for factory review.
2. Vibration testing should be recorded when possible and micro panel trending or preferably Data Logging of the system operation at the same time as the vibration information is collected. Data sampling should be at 5 seconds during the vibration testing.
3. Determine if re-grease maintenance was performed as specified in the micro panel re-grease schedule.
4. If the chiller is operating check for elevated bearing temperatures (150°F or 65°C is high end of normal), vibra-tion or unusual sounds.
5. If the chiller is not operating the NDE (non-drive end) bearing cover should be removed to inspect the grease color and bearing cage integrity.
6. The grease in the bearing or cap should be removed for a sample, the lab will require a teaspoon of grease per test. If looking at wear, you would want to make sure the sample collected is relative to the contact areas and sent for testing to the lab of your choice. NOTE: If under factory warranty contact PTS for WEG preferred lab address.
7. The motor to the compressor alignment should be verified.
Work on this equipment should only be done by properly trained personnel who are qualified to work on this type of equipment. Failure to comply with this requirement could expose the worker, the equipment and the building and its inhabitants to the risk of injury or property damage. The instructions on this service information letter are written assuming the individual who will perform this work is a fully trained HVAC & R journeyman or equivalent, certified in refrigerant handling and recovery techniques, and knowledgeable with regard to electrical lock out/tag out procedures. The individual performing this work should be aware of and comply with all Johnson Controls, national, state and local safety and environmental regulations while carrying out this work. Before attempting to work on any equipment, the individual should be thoroughly familiar with the equipment by reading and understanding the associated service literature applicable to the equipment. If you do not have this literature, you may obtain it by contacting a Johnson Controls Service Office. Should there be any question concerning any aspect of the tasks outlined in this bulletin, please consult a Johnson Controls Service Office prior to attempting the work. Please be aware that this information may be time sensitive and that Johnson Controls reserves the right to revise this information at any time. Be certain you are working with the latest information.
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BEARING INSPECTION1. To remove NDE bearing cover, first remove the top and bottom grease tubes from the cover.
2. Next remove the top left bolt and the bottom right bolt and insert a metric threaded rod or stud bolt. This is a very important step as the inboard bearing cover can be dislodged and the preload springs could fall out of the cover or the cover could rotate preventing the re-insertion of the cover bolts. Use caution not to push the studs inward to dislodge the inner bearing cover.
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Stud InsertedNote the Darkened Grease
3. The grease color should be Blue or possibly a Green color depending on how long the motor has been in op-eration. Green is an acceptable color for grease age, dark gray or black indicates the presence of iron oxides, possibly from bearing cage wear.
4. Clean the grease from the cage and ball assembly to allow for a visual inspection of the cage condition. It is important to look for the equal spacing of the cage assembly between the races. Look to see if the cage has fallen down and is contacting the inner or outer race. Be sure to look at the bearing all the way around as the contact may be only on the top with the cage contacting the inner race, or only on the bottom with the cage contacting the outer race.
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Correct spacing of the cage
Incorrect spacing, cage touching inner race
Cage wear from cage rubbing the inner race
Checking for cage movement
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5. The cage wear is a result of the ball to the race clearance increasing from contacting the ball and wearing or an enlargement of the cage to ball diameter.
6. An additional check to be made is to see if there is any vertical movement of the cage. This can be accom-plished by using your fingers to lift the cage up and down or by using a pocket screwdriver to GENTLY lift the cage to see if it will move. DO NOT APPLY A LARGE FORCE WITH THE SCREWDRIVER AS CAGE DAMAGE COULD OCCUR. The cage clearance is approximately .010” so the cage movement should be very small about .005”in the vertical direction. Any movement greater than .005” could be an indication of cage wear, if the cage is worn then you should see unequal spacing of the cage. If there is no vertical movement of the cage and the cage is centered with no race contact marks the bearing is suitable for service.
CORRECTIVE MEASURES1. If the motor was stopped due to an unusual noise, vibration or elevated temperature and the grease is not
dark gray or black, the cage does not show any signs of wear or damage, then the bearing can be cleaned and re-greased correctly (see proper greasing in this document). After proper cleaning and re-greasing the motor should be able to be placed back into service.
2. If the bearing shows any signs of the wear conditions as described above (dark grease, cage movement or cage contacting the race) the bearing will have to be replaced.
3. Prior to removing the bearing the bearing has to be marked as shown in the diagram below. These markings will assist in the forensic analysis of the bearing for root cause analysis.
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NDE or DE TOP
OUT
OUT
1
2
3
4
56
7
8
9
10
LABEL THE BEARING AS SHOWN BE SURE TO INDICATE DRIVE END (DE) OR NON DRIVE END (NDE)
WHEN A BEARING IS REMOVED FROM A MOTOR, PLEASE MARK THE BEARING WITH A PERMANENT MARKER AS SHOWN BELOW.
WIPE OFF GREASE FROM AREA TO BE MARKED SO THAT THE MARKINGS ARE NOT EASILY WIPED OFF
Place Site name on both races
Mark direc�on of rota�on
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BEARING REMOVAL1. Clean any excess grease from the bearing, any paint or debris on the shaft so that the slinger ring can be re-
moved.
2. Set up proper rigging devices and remove the motor cooling hood on the top of the motor.
3. Remove the slinger ring by removing the four screws that retain the locking collar. Remove the locking col-lar and circlip from the shaft, with the locking collar removed the slinger ring can be pulled off the shaft. The slinger ring is a very tight fit so care must be used to not cock the collar as the collar will then get stuck on the shaft. Steady constant straight force should be used to remove the collar.
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Remove the four metric thread Allen screws
4. Both the drive end and the non-drive end have RTD’s that are wired back to a junction box on the non-drive end of the motor. These RTD’s must be disconnected at the junction box in order to remove the end bells. A wire or a string must be firmly connected and taped to the RTD terminal ends before pulling the wires out of the junction box. This wire or string will be used to pull the RTD wires back to the junction box when the end bells are installed. The drive end wires are very long as they travel the full length of the motor, allow for this distance when attaching the wire or string.
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Wire installed to pull back the RTD wires to the junction box DE
RTD Wire
Position L5010, L5809 e L5810/11End Shield M16x2.0Bearing Cap M10x1.5Grease pipe support M6x1.0
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5. Remove any bolts or studs retaining the inner bearing cover as the end shield will not come off if there are bolts inserted in the inner bearing cover.
6. Place eye bolts of the correct thread size (Metric) in the end shield lifting locations. Use the correct load rated shackles and slings for the end shield removal. Set up a gantry or chain falls as necessary for the safe removal of the end shield.
7. Remove the top two bolts that retain the end shield to the motor, insert a threaded rod of the correct metric thread size (see chart above) to help align the end shield during the removal process.
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Guide Rod Holes
8. Evenly and slowly pry the end shield loose from the motor, taking caution to be certain that the gap is equal all the way around the end shield.
9. After the end shield is removed the bearing can be removed from the shaft by use of a three prong bearing puller. Apply constant, even, force during the removal process to prevent the bearing from getting cocked or stuck on the shaft. (NOTE: Add a plate between the rotor shaft and puller rod to protect the rotor inner threads from damage by the puller when screwing in the puller bolt)
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INSTALLING THE NEW BEARING1. An induction bearing heater or cone heater will be required to install the new bearing on the motor shaft. The
bearing must be filled with PolyRex EM grease (Blue in color) as shown below prior to heating. The white grease shown is for illustration only.
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2. Before installing the new bearing the inner bearing cover must be cleaned and free of dirt and debris. The pre-load springs must be installed in the bearing cover, the cover should be filled evenly as shown to 75% full with new clean Polyrex EM grade 2 grease.
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3. Install the clean properly greased inner bearing cover on the motor shaft.
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4. Inspect the bearing mounting surface to be sure there is no paint, scratches or burrs that would impede the bear-ing from sliding onto the shaft. Burrs and paint should be removed using very fine sand cloth (200 grit) using care to not dimensionally change the shaft dimension.
MOUNTING BEARINGS USING HEAT1. The force required to mount a bearing increases with the bearing size. Because of the force required larger
bearings cannot easily be pressed onto a shaft or into a housing. Therefore the bearing or housing will require heating prior to installation.
2. The temperature difference between the bearing, shaft or housing depends on the interference fit required for the application. Normally a bearing must be heated to at least 80°C to 95°C (144°F to 203°F) above the ambient shaft temperature. Never heat a bearing to a temperature above 125°C (257°F) unless specified by the bearing or motor manufacturer. Extreme heat can cause the bearing metallurgy to change and may affect the hardness or alter the diameter. Never use an open flame or locally heat the bearing creating hot spots.
3. Wear clean protective gloves rated for at least 300°F when mounting the hot bearing. Lifting gear can help in installing a bearing. Push the heated bearing onto the shaft immediately after removing the bearing from the heater to prevent the bearing from cooling. Slide the bearing on in a one swift movement being sure to press the bearing up to the shaft collar.
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4. Bearings, SKF (2003) Mounting bearings using heat. Retrieved from www.lubsys.com/knowledge/knw_heat-mnt.htm
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5. Insert guide pins into the inner bearing cover bolt holes for alignment to the end shield.
6. Before installing the end shield it may be required to insert a lifting eye into the threaded hole in the shaft end to help lift the shaft to the proper height to be certain that the end shield will slide on correctly.
7. Install the NDE end shield using guide pins in the upper bolt holes or guide pins in the lower bolt holes on the DE, and align the inner bearing cover guide pins to the end shield.
8. Pull the RTD wires back to the junction box using the wire or string inserted upon disassembly.
9. Insert the fasteners in the bottom (NDE) or top (DE) bolt holes when the end shield is correctly in place. Re-move the upper guide pins and insert the fasteners and tighten all the bolts. (Torque?)
10. Install the slinger ring and locking collar taking care to slide it on carefully. Insert the four retaining screws on the locking collar.
11. Next pull on the inner bearing cover guide pins to be sure the cover is inserted into the rabbit on the internal side of the end shield. Install the properly cleaned outer bearing cover and install two bolts tighten to (See Ap-pendix for torque values). Remove the guide pins and insert the last two bolts and tighten.
12. If the motor has an Aegis grounding collar install as shown below.
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13. Install the grease fill and drain line.
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PROPER GREASING (MOTOR LUBRICATION SI0415)A properly greased bearing should appear as shown below.
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Excess grease may elevate the bearing temperature. After starting the motor be sure to monitor the bearing tem-perature. The bearing temperature may elevate but should return to normal after 1 hour of operation. The drain plug should be left open during this time to allow any excess grease to drain out. For more information on motor lubrica-tion see: Motor lubrication (SI0415).
