General Service Manual - Continental Electric Motors
Contents
1. catastrophic failure being imminent e Does the ambient temperature vary significantly daily or seasonally e Can the driven equipment overload occasionally and cause nuisance tripping e In the event of overloads are the trained operators nearby that can adjust load requirement The following table contains some traditional alarm and tripping point settings It is also based on the condition that the motors are in 600 3600 rpm Anti Friction Alarm 100 deg C Shutdown 110 deg C Sleeve 82 100 If sensor in oil bath 60 65 17 Balance and Vibration This section is not meant to be a scholarly discussion on vibration but a background discussion on motor vibration and some general guidelines from a maintenance standpoint Why is vibration important A reduction in vibration will result in longer bearing life reduced noise and less stress on the motor frame and base Also as energy goes into vibration efficiency is somewhat reduced Vibration in a motor can be the result of many factors It s important to understand these when trying to analyze vibration issues Some of the major items that can contribute to motor vibration are Rotor unbalance Firmness of the mounting foundation Shaft to bearing fits Bearing to frame fits Shaft straightness Bearing Journal Runout Non uniform windings electrical unbalance Uneven Airgap Alignment of the rotor within the frame Alignment of the motor to the driven equipment Thrust on2. OIL SETTING IN INCHES Nro OIL RESERVOIR EDGE OF BOTTL ER CAF N BOTTOM EIGE OF CAF OIL fETTING IN INCHES Oil lubrication of Sleeve Bearings Sleeve bearings are lubricated the same way as ball bearings The motor was shipped from the factory without lubricating oil Oil must be added through oil ring viewing port on the upper side of the bearing housing before the motor can run Do not fill the bearing housing beyond the mid point of the bearing housing oil level sight gauge Use only high quality turbine oil with a viscosity of 150 200 SSU 100F for normal ambient of 20F to 110F The frequency of inspection including addition of oil changing the oil and checking the bearing wear is best determine by a study of the particular operating conditions Continental modern types of sleeve bearing housing are relatively dust and oil tight and require very little attention since the oil does not become contaminated and oil leakage is negligible Maintenance of the correct oil level is frequently the only upkeep required for years of service with this type of bearing If the motor is to be stored long before installation sleeve bearing oil chamber should be filled to the mid point of the bearing housing oil level sight gage and then turn the shaft at least ten or twenty times to insure that the shaft journals are completely covered Every few months the shaft should be rotated a few turns for rust prevention 26 Grease
3. from a power source e Air Filters o When filters are provided standard on WPII enclosures Continental supplies Stainless Steel washable filters We suggest that filters be cleaned whenever the pressure drop across the filter exceeds 15 WG e Motor Grounding Provisions Grounding provisions on a motor will vary according to the owners specification Some of the most common methods of grounding are as follows o A ground connector placed in the main conduit box or on the motor frame is the most common When the servit post is installed in the main conduit box it replaces one of the mounting bolts for the box If mounted outside the box it is mounted into a hole drilled and tapped into the frame A copper or steel ground pad can be brazed or welded to the motor frame The pad is then drilled and tapped to accept a cable terminal to be bolted to the frame 22 Oil Lubrication General It is very hard to set up a re lubrication schedule in the abstract The conditions in which the motors operate such as high and low ambient temperature dust chemical environment ventilation paths around the motors duty cycle moisture etc All play an important role in the lubrication cycle and these are best known to the motor users A re lube should take place when the lube is depleted burned out or contaminated Therefore the following recommendations are offered as a guide The maintenance people must analyze the lube requirements of eac
4. clearance Thrust Bearings Some motors due to the application requirements have Thrust Bearings to handle the axial load imparted from the driven equipment If your motor has been supplied with a thrust bearing it should not be run for more than a few minutes unconnected to the load as the rolling element is likely to skid and slide instead of roll due to less axial loading than it was designed for Damaged caused in this fashion is not considered a warranty failure 11 ae E CONTINENTAL 4 Ns REMOVAL AND REPLACEMENT OF SLEEVE BEARINGS SECTION VIEW TOTALLY ENCLOSED FAN COOLED SQUIRREL CAGE INDUCTION MOTOR WITH OIL LUBRICATION SLEEVE BEARING E AN WEA gt 1N FAN GRID BEARING HOUSNG j BEARING CAP N BEARING BRACKET BOTTOM HALF FAN COVER The sleeve bearing can be replaced without removal of the bottom brackets and without disturbing the motor alignment or removing the coupling SECTION VIEW WEATHER PRTECTED TYPE II SQUIRREL CAGE MOTOR WITH OIL LUBRIC ATED SLEEVE BEARING TOP FILTER BOX A INPUT AIR DUCT An Y MO T TmT Sl i a O 1 Y ian ry E LLU E r insu HOUSING BEARING CAP N BEARING BRACKET BOTTOM HALF The sleeve bearing can be replaced without removal of the filter box or bottom brackets and without disturbing the motor alignment or removing the coupling Remove both input air ducts and their supporting pieces wh
5. shut down temperature at the nominal insulation system limit However this approach does not allow for any brief periods of over loads or abnormal environmental conditions It can also cause a lot of needless nuisance tripping and costly production stoppages that should never be allowed to happen The following table contains some traditional alarm and tripping point settings based on the class of insulation used in the motor It is also based on the condition that the motors are in 600 3600 rpm Class Type Alarm Shutdown Insulation Motor Winding Bearing Winding Bearing B Open 130 deg C 100 deg C 140 deg C 110 deg C B TEFC 130 deg C 100 deg C 135 deg C 110 deg C F Open 165 deg C 100 deg C 175 deg C 110 deg C F TEFC 165 deg C 100 deg C 170 deg C 110 deg C The temperature given for alarm point represents the values specified for Hot spot allowance as defined as being 10 deg C over the temperature rise by resistance The choice for setting of an alarm and set points should be considered to the following A How critical to the operation of the plant or facility is the motor B Will safety be affected if the motor strips because of the setting without a catastrophic failure being imminent C Some times the only thing affected by exceeding the rated insulation temperature is the insulation life Even then it decreases the life based on the time the rated temperature is exceeding D Does the ambient t
6. the bearing in the race In this case measurements in the field under load are more meaningful 19 Other Accessories e Non Reverse Ratchet o For motors equipped with non reverse ratchets Continental uses a pin type designed that prevents the motor from being driven in the opposite direction by the pump when it is shut down Caution should be observed when applying non reverse ratchets due to pump head conditions and the motor should not be subjected to abnormal use including frequent stopping and starting of the motor For rotation check the name plate on the motor e Non Reverse Clutch o Continental will usually utilize an overrunning centrifugal throwout type clutch There is no regular maintenance to perform except for lubrication Clutches can be oil or grease lubed to be consistent with the motor bearing lubrication Information on the maintenance of the clutch will be supplied with the order documentation as it is dependent on manufacturer and model chosen e Space Heaters o Space heaters should be used in any installation where warm humid air can contact a cold motor causing condensation to occur Space heaters are used to elevate the temperature inside the motor by 5 10 degrees F in order to prevent condensation within the motor during storage or shut down situations o Space heaters are usually mounted on the end turns or mounted to the frame inside the motor enclosure They should be interlocked with the motor c
7. the same General The repeated stressing of the balls and races as a bearing rotates ultimately causes fatigue failure of the metal The higher the load the higher stress and the shorter the time until the bearing fails Bearings are rated by their probability of fatigue failure Bearing manufacturers have tested many groups of identical bearings under heavy loads to the point of fatigue failure Bearings in a group have been found to have different lives even though they are under same loads For this reason bearings are rated for either minimum life or average life The life which 90 of a group bearing will exceed is known as the minimum life A commonly used term as L10 The life which 50 of a group bearing will exceed is the median life L50 and is approximately five times the minimum life Minimum bearing life is a period of time base on continuous operation at design load Bearing Internal Clearance General e Bearings are designed with a specific internal clearance that measures the total clearance between the rings and the rolling elements Internal clearance provides o Free rotation of rolling elements o Compensation for thermal expansion o Optimum load distribution e Choosing the correct internal clearance is important because bearings hold shaft armatures gears and other rotating devices in proper alignment The amount of internal clearance influences noise vibration and heat build up and fatig
8. to the bearings Caution In many cases thrust bearings utilize a heavier lubricant than standard anti friction bearings Refer to the motor lubrication nameplate for lubrication requirements The top bearing oil reservoir should be kept filled to the oil level mark on the sightgauge The static oil level should not exceed the center line of the lowermost ball or roller Overfilling can cause churning which results in abnormally high operating temperatures Systems of this type normally employ sight gauges to facilitate inspection of the oil level The oil level may change slightly when motor is running because of the circulation of oil Check the oil periodically for contamination The oil may be drained from the oil pot by removing the bottom pipe plug from the level gauge Evidence of oil leak should be checked to determine the source Horizontal Lubricated Bearings This system is designed to lubricate the motor bearing directly upon start up An oil ring is used to lift the oil from the reservoir in the oil guide The oil is lifted up and is guide directly on the balls of the bearing as they spin Once the oil has passed through the bearing it is drained into the oil reservoir All Continental oil lubricated motors are completely tested and ready for successful operation when they leave the factory Before installing inspect the motor carefully to determine that no damage has occurred during transit Turn the rotor by hand a few times to se
9. turning the air blast on the machine In blowing dust out of machines the adjacent machine should be protected from flying dust by a suitable cover or shield o Suction Cleaning by a vacuum cleaning system is the preferred method as all dirt is carried away from the machines and the danger of blowing dirt into adjacent machines is completely avoided o Wiping All accessible insulated parts subject to copper or carbon dust should be wiped clean with a dry cloth in addition to cleaning by suction or compressed air When wiping do not neglect such parts as inner surface of end windings strip ring insulation etc o Solvent The use of solvents should be avoided in so far as practical and only used whenever it is necessary to remove hard or pasty deposits of grease oil and other foreign matter Before using any solvent use a clean dry rag to wipe off as much dirt as possible as mentioned in paragraph C Then use a rag moistened not dripping with a petroleum solvent of the safety type such as Stoddard Solvent No 1609 2 or equivalent If a petroleum solvent has a little effect on the dirt trichloroethane may be used However precautions must be taken as trichloroethane is an active solvent and somewhat corrosive in its action Do not use on leads or other rubber insulation because it has a deteriorating effect on these items Thorough drying afterwards is essential to avoid damage to the insulation o Steam clean o Dry Ice clea
10. vertical motors is it present during the test All manufactured products have unbalance Balancing compensates for less than perfect manufacturing Most motor manufactures use two plane balancing that is balance weights are added to an element near each end of the rotating assembly API541 asks for 3 plane balancing This requires adding or subtracting weight at the center of the rotor This can be necessary if the motor is of flexible shaft design and the rotor will flex due to imbalance at the center Balancing in this 3rd plane compensates for this If the motor is of stiff shaft design this third plane balance is not necessary There are two components of rotor unbalance that affect the amplitude of vibration The first component is the residual unbalance left in the rotor The second and more critical component is the speed of the machine For a given amount of residual unbalance the vibration amplitude increase with the square of increase speed For example if you have a shaft that vibrates at 03 in s peak at 1800rpm it will vibrate at 12 in s peak at 3600RPM Since you doubled the speed the vibration amplitude increases by the square of the speed increase 18 Prior to assemble ALL Continental rotors are balanced to less than 2 0z in per plane After assembly ALL Continental motors receive a routine test during which vibration measurements are taken The table below show s the NEMA standards and the Continental acceptable limits for
11. when high thrust due to pump action or shafting is present As standard Continental sizes thrust bearings for a 7 year average life For normal thrust amp slow speed conditions Continental recommends a Super Conrad type ball bearing grease lubrication for most durability but less maintenance 23 Angular Contact Bearing Lubrication Angular contact thrust bearings with bronze or phenolic cages are mounted according to thrust requirements The lube system is designed to lubricate the entire assembly from top to bottom An impeller is used for lifting the oil into contact with the bearings The impeller pumps the oil up from the oil chamber through the drilled hole in the cartridge housing from which the oil flows downward through the bearings by gravity Attention is called to the drilled holes which prevents possible siphoning out of the oil when the shaft is stationary The oil is immediately available upon once the motor is started Spherical Roller Thrust and Pivot Shoe Bearings For special thrust applications with oil bath motors spherical roller bearings or pivot shoe bearings are used when specified Caution Do not lay the motor on its side as this will damage the spherical roller or pivot shoe bearings Install coupling with motor in a vertical position Do not run the motor for even more than a few minutes without being connected to the load as the lack of axial loading may cause the bearings to slide or skid and thus damage
12. 2 megohms per each 1000 volts of operating voltage plus 1 megohm corrected to 40 degrees C If the meggar reading is not satisfactory the motor windings must be dried out prior to connection Contact Continental for advise on how to proceed Drying out the windings is not considered a warranty item 3 Long term storage long term storage is defined as over 6 months e Store the motor in it s normal operating position in a well ventilated clean dry environment free from vibration and condensing humidity cover machine with a tarp and energize the space heaters to keep the temperature of the winding a few degrees above the surrounding air If machine does not does not have space heaters auxiliary heat should be used to keep the windings warm and free of condensation e Shaft should be rotated by hand every month to keep the bearings lubricated for rust and corrosion prevention and to change the position where the balls rest on the shaft to reduce the chance of brinelling e For a grease lube motors the grease cavity should be completely filled with a moisture resistant grease for storage e Upon removal from storage the bearings should be inspected for corrosion and brinelling prior to installation and should be re lubed with an appropriate amount and quality of grease or oil e The windings should be meggered before connecting on line The reading should be approximately 2 megohms per each 1000 volts of operating voltage plus 1 m
13. General Service Manual Continental Electric Motors Inc Phone 800 335 6718 www cecoinc com sales cecoinc com INDEX Topic Warnings Receiving amp Inspection Storage Installation Maintenance General Anti Friction Bearings Sleeve Bearings Winding Temperature Protection Bearing Temperature Protection Balance and Vibration Other Accessories Oil Lubrication Grease Lubrication Wound Rotor Motor Supplement Services 12 15 17 18 20 23 27 28 29 1 Warnings This equipment should only be worked on by trained qualified electrical personnel familiar with the construction of this equipment and the hazards involved in working on this equipment The manual should be read in it s entirety and understood prior to proceeding Failure to follow these precautions could result in severe bodily injury or loss of life When servicing all power sources to the motor and it s accessories should be disconnected and the motor should not be rotating The frame of the motor must be grounded in accordance with the National Electric Code The shaft key must be removed or be fully captive prior to the motor being started Explosion proof motors should only be installed in accordance with the classification listed on the nameplate Repairs on these motors should only be made by Continental or a UL approved service provider The motor is provided with lifting lugs or eyebolts to
14. Lubrication Grease lubricated motors are sufficiently lubricated to operate under NORMAL CONDITION for approximately one year in a redundant system running continuously A relubrication schedule will vary widely with motor size type of service and environment On horizontal motors the shielded side of the bearing is placed toward the inside of the motor On vertical motors shield is on the bottom side of each bearing in order to keep the grease contact with the bearing On vertical motors with special shaft extension diameters there may be a grease retainer which is a separate component of the bearing It is very hard to set up a relubrication schedule in the abstract The conditions in which the motors operate such as high and low ambient temperature dust chemical environment ventilation paths around the motors duty cycle moisture etc All play an important role in the lubrication cycle and these are best known to the motor users A relube should take place when the lube is depleted burn out or contaminated Therefore the following recommendations are offered as a guide The maintenance people must analyze the lube requirements of each motor and determine its condition if the oil or grease smell burnt if the grease is dry and hard if it feels gritty to the touch then it is time to change the lube Regreasing is ok for the intervals between major overhaul period but Continental would recommend the entire grease cavity be cleaned out a
15. aid in unloading and positioning These are sized for lifting of the motor and standard accessories only Lift the motor using all the lugs and use spreader bars as necessary The lifting straps or cables should never be pressed against the motor as they may cause damage The lifting lugs should never be used to move the motor when connected to pumps gearing or other equipment Receiving and Inspection Caution The motor is provided with lifting lugs or eyebolts to aid in unloading and positioning These are sized for lifting of the motor and standard accessories only Lift the motor using all the lugs and use spreader bars as necessary The lifting straps or cables should never be pressed against the motor as they may cause damage The lifting lugs should never be used to move the motor when connected to pumps gearing or other equipment 2 Receiving e Continental motors are completely inspected tested and ready for successful operation when they leave the plant Upon removal from the delivering vehicle carefully inspect the motor for any damage caused by the carrier during transit and immediately report this to the carrier and Continental Do not accept the motor until the carrier has made an e appropriate note of the damages on the bill of lading e If any concealed damage is discovered later notify the carrier at once and have them make an immediate inspection e Compare Nameplate data with the order acknowledgem
16. brushes are replaced before they reach their limit of travel and break contact with the slip ring E Remove any free copper picked up by the face of the brush F When a new brush is installed be sure it is free in the brushholder 28 Services Continental Electric Motors is committed to providing an extensive range of services to maximize your operation While this manual is designed to cover the customary procedures and most common problems which arise in the maintenance of motors operating conditions vary widely and many questions may arise which could not be answered within the confines of these few pages In such cases it is suggested that you contact Continental for the proper procedures for your specific type of motor Please have the motor serial number available We would be happy to assist you Spare Parts Wear and replacement parts are always available All components are manufactured either in our own facility or acquired from vendors pre qualified to our quality standards For fast and accurate replacement parts all you need is to obtain a motor serial number Refurbishment of Continental Motors Continental can refurbish any of the motors that it has manufactured We completely evaluate the motor upon receipt with inspections and testing and then recommend a path forward based on this documented information When we are finished you we return a motor in like new condition with a 1 year I service warrant
17. e that it turns freely in its bearings without undue noise or friction 24 ONTINENTA INSTALLATION The motor must operate on a level base and oil pipes must be level Make sure all pipe connections and pipe plugs are tight Check oil level settings as shown lubricating instruction plate on motor Measure setting from edge of frame to bottom edge of oil cup cap If necessary to adjust oil level setting loosen set screws in cap Set screws must be tight after oil settings have checked Caution To fill oil reservoir unscrew bottle from cap and fill bottle through the stem with a light turbine oil having a viscosity of 40 45 SSU at 210 F Screw bottle back into cap Repeat procedure when bottle empties until oil level remains stationary This will indicate that the correct amount of oil is in the bearing reservoir Allow at least 20 minutes for oil to enter reservoir before starting the motor MAINTENANCE Always keep a visible supply of oil in the bottle Do not refill the bottle if more than 1 4 of oil is visible in the bottle Too frequent filling of the bottle will flood the oil reservoir Unusual loss of oil indicates a leak investigate Check oil pipe connections If motor is kept idle run motor a few seconds every two months to distribute oil in the bearings Horizontal Motor BOTTLES E BOTTOM EDGE OF CAP L 4 a p TO BEARING QIL SETTING RESERVOIR IN INSHES 25 Vertical Motor
18. eak value of incoming voltage surges The arrestors are mounted in the main conduit box and are connected from the main leads to ground as near to the motor as possible 21 e Surge Capacitors o Surge capacitors are designed to lengthen the rise time of a surge The capacitors are mounted in the main conduit box and are connected from the main leads to ground as near to the motor as possible Insulated Bearings o Insulated bearings are used to prevent shaft currents from causing pitting on the bearings resulting in premature bearing failure A motor may have one or both bearings insulated as requested by the customer If Continental has been advised that the motor is to driven by a VFD we will supply an insulated bearing on the Opposite Drive End If insulated bearings are provided then oil piping vibration and temperature probe connections if provided should also be insulated Tachometers Encoders o A variety of tachometers and encoders can be provided based on spec requirements These are devices providing instrument level signals and are fragile in relationship to the robustness of the motor Never force the coupling on the shaft of the device If the coupling will not slide on easily use an emery cloth on the shaft until the coupling can be slipped on e Removable Link o This is a short segment of buss bar mounted between two insulating studs The links can be removed to totally insure that the motor is disconnected
19. egohm corrected to 40 degrees C If the meggar reading is not satisfactory the motor windings must be dried out prior to connection Contact Continental for advise on how to proceed Drying out the windings is not considered a warranty item e Any reconditioning required as noted by the inspections after removal from storage should be performed prior to putting the motor into service These reconditioning are not considered a warranty item Failure to follow these procedures may void the warranty 4 Installation Install motor on a solid level flat base and securely bolt in position before starting Shims may be required to assure that the motor is installed in a level position Never torque down the motor to meet the shim Shim properly so that the motor frame does not flex as it is tightened to the mounting base No foot should move more than 002 when it s mounting bolt is loosened Use a dial indicator to check during installation Motor must be accurately aligned with driven unit Misalignment between direct connect shafts will cause increase bearing loads and vibration even when using a flexible coupling Alignment checks should be made prior to running It may be necessary to recheck these values when the motor is hot in order to compensate for thermal expansion Shaft angular misalignment must not exceed 0003 per inch of coupling hub radius Shaft parallel misalignment must not exceed 003 The coupling shou
20. emperature vary significantly daily or seasonally E Can the driven equipment overload occasionally and cause nuisance tripping F In the event of overloads are the trained operators nearby that can adjust load requirement Remember A winding is too hot only when actual temperature exceeds the insulation thermal limit not just when the rise above ambient exceeds the nameplate figure 16 Bearing Temperature Protection There are a number of devices that can be used to monitor the temperature of the bearings and provide a signal to an alarming device A listing of commonly used devices is as follows Bearing Thermostat or Bearing Temperature Relay Resistance Temperature Detectors RTD Thermocouple TC The Setting of Temperature Protection Devices Many times the manufacturer of motors is asked by users of motors and engineers writing specifications to recommend settings of alarms and shutdown devices However the motor manufacturer is not in the best position to know the correct answer for all situations The most that can be expected of the motor manufacturer is for him to give general guides lines for the appropriate settings The alarm and tripping point setting should be based on operation conditions Generally the users or the driven equipment manufacturers are in a better position to know the details required to make the proper selections Generally a conservative practice is to set a shut down temperature at the no
21. ent so that the motor is properly identified upon receipt e Motors are typically shipped FOB our plant The responsibility for receiving inspection notification to the carrier and collection for damages if any lies with the purchaser Storage If the motor is not to be immediately installed it will need to be stored in an appropriate manner to avoid damage Short term storage 6 months or less e Store the motor in it s normal operating position in a well ventilated clean dry environment free from vibration and condensing humidity cover machine with a tarp and energize the space heaters to keep the temperature of the windings a few degrees above the surrounding air If machine does not does not have space heaters auxiliary heat should be used to keep the windings warm and free of condensation e If the motor is oil lubed it has been shipped without oil As soon as the motor is received the oil reservoir should be filled to the proper level with an appropriate lubricating oil If the motor is equipped with oil sump heaters they should be energized e The motor shaft should be rotated by hand every month to keep the bearings lubricated for rust and corrosion prevention and to change the position where the balls rest on the shaft to reduce the chance of brinelling e Grease lube motors are shipped with their grease cavities filled e The windings should be meggered before connecting on line The reading should be approximately
22. f after removing the two socket head screws 6 Remove the bearing temperature detector and save Pull the detector body away from the flat surface of the bearing joint DO NOT PULL ON THE DETECTOR LEADS 7 Measure and record the insulated positioning stud projection from the bearing body Note the stud must be assembled with the same projection 8 To remove the lower bearing half relieve the weight of the rotor by the use of a wooden lever approx x 2 x 24 placed against the shaft bottom and using the bearing cap rabbit fit as a fulcrum or by the use of a sling hoist 9 Raise the shaft only several mils to free the bearing bottom half which can be rotated 180 The 10 Oil ring is now pushed toward the inside of the motor and off the bearing Lift out the bearing half Note Before lifting the rotor be sure to loosen the bearing housing bolts on the opposite bearing to prevent damaging the other sleeve bearing 14 Part 3 Inspecting the Bearings 1 Make sure the shaft has no nicks or burs The shaft should be perfectly smooth and have a surface finish of 32 microinches or smaller 2 Check the Babbit of the bearing to confirm that no Wipes exist A wipe is characteristic of a rub 3 The babbit should have a dull smooth finish If the babbit has a mirror finish this is indicative of the shaft to bearing tolerance being to small Consult the factory for the recommend tolerance for your partic
23. h motor and determine its condition if the oil is burnt or if it feels gritty to the touch then it is time to change the lube Adding oil is ok for the intervals between major overhaul period but Continental would recommend the entire oil reservoir be cleaned out and filled with fresh oil during the major overhaul ideally within one or two year periods Oil change schedule Because of the various unknowns Continental would recommend that the oil be checked at six months or 1500 2000 hours of operation whichever comes first If the oil is not burn or not contaminated continue to use it checking again at approximately 300 hours intervals until a definite time can be set for each motor s oil change If you want to be on the conservative side change the oil every six months or 2000 hours intervals but this can be a wasteful effort Recommended Oil Exxon Teresstic 32 Gulf Harmony 32 Citgo Pacermaker 32 Texaco Regal R amp O 32 Mobil DTE Light Any turbine oil with a viscosity of 44 SSU 210F 155 SSU 100F this viscosity corresponds to an SAE 10 non detergent weight Vertical amp Horizontal oil lubrication systems When motors are equipped with an oil lubrication systems we run the motor to test for proper oil circulation prior to the standard routine test After completion of the routine test the oil is drained for shipment as it is considered a hazardous material Vertical motors are frequently used with oil lubrication
24. ich are bolted to the frame so that the bearing housing and bracket are exposed 12 c HS CONTINENTAL a _BRACKET TO FRAME SCREWS FRAC KET TOP HALF TO BCOITOM BRACKET SCRE WE Part 1 Accessing the Bearing Housing 1 For the Non Drive End of a Totally Enclosed Fan Cooled Machine you will have to remove the fan cover from the motor in order to access the bearing bracket and sleeve bearing assembly 2 Remove the four bolts holding the bearing bracket top half to bearing bracket bottom half 3 Remove the four bolts holding the bearing bracket top half to the stator frame 13 ONTINENTAL _ SOCKET HEAD SCREW LOCATED ON TOP TOP HALF DN mo e Te TWO BEARING TEMP DETECTOR LEADS INSIDE OF MOTOR CS OUTSIDE OF MOTOR _BRG POSITION STUD WITH INSULATED CAPS serna 7 fl 4 BOTTOM HALF U OIL RING SLEEVE BEARING Part 2 Removing the Bearing 1 Remove the four bolts holding the bearing housing to the bottom bearing bracket 2 Remove the bearing cap on the opposite drive end Back off the drive end bearing cap 3 Cut the bearing temperature detector leads approximately in the middle Note these leads exit the top of the bearing housing 4 Break the seal of silicon between the bearing housing and bottom half of the bearing bracket and remove the upper bearing housing 5 Lift off the upper bearing hal
25. ings at machine terminals be sure other cables switches etc are isolated e Whenever motor driven or electronic instruments are used to take readings over a period of time longer than one minute as in the case of dielectric absorption curves it is essential that before a repeat reading of the same part is taking that the winding be discharged to ground for a time at least equal to the total time of voltage application when readings were first taken Cleaning General e Oil or grease covered machines should be cleaned thoroughly and a fresh coating of insulating varnish applied Usually most of the oil or grease can be removed with a cloth moistened with a solvent such as VM amp P Naptha A brush should be used for surfaces difficult to reach by hand Use a spray gun to clean inaccessible slots and passages After using the solvent be sure to dry the windings with compressed air or can be cleaned with steam cleaner and detergent e No amount of cleaning will repair insulation which has been badly oil soaked Warning Do not use a solvent which has toxic effects or which has a deteriorating effect on varnish 7 Cleaning Methods o Compress air This is the most important convenient method if there is an excessive amount of dirt or oil present Air pressure should be less than 50 psi excessive pressure is capable of injuring the insulation o Use dry air and allow any accumulation of water in the pipes to be blown out before
26. ld never be pressed or driven onto the shaft It should be heated for proper mounting There should be sufficient area around the motor so that air flow to the motor for cooling is not restricted in any way Before connecting power check nameplate date for motor power requirements and be sure that the supplied utility power is appropriate Do not try to run the motor on any other current voltage or frequency than that for which it was designed Before connecting motor to the load check the nameplate data for motor speed and be sure that it matches the speed requirements of the driven equipment Check for motor rotation consistent with the direction required by the driven equipment prior to connecting motor to the load Also check to be sure that the shaft will rotate freely by hand Failure to follow this step may result in damage to the driven equipment and or bodily injury or loss of life If it should become necessary to reverse the direction of rotation simply interchange the connections of any pair of leads Caution Do not connect energize the motors until bearing lubrication has been checked Oil lube motors must have their oil reservoirs filled to the proper level with an appropriate lubricant Grease lube motors must be greased properly Oil mist motors must have the oil mist system connected and operational prior to running the motor Refer to the Lubrication section of this manual for further information Installation sho
27. minal bearing temperature limit However this approach does not allow for any brief periods of over loads or abnormal environmental conditions It can also cause a lot of needless nuisance tripping and costly production stoppages that should never be allowed to happen Once an operating temperature has been established it is reasonable to expect this temperature to remain at a fairly constant value above ambient temperature Instead of arbitrarily setting relays and alarms it is recommended that the operator set the alarm temperature at some reasonable value around 10 deg F above maximum expected temperature Allowance should be made for normal changes in ambient and other fluctuating conditions to prevent unnecessary tripping of relays With the alarm set as suggested an early warning would be given if any unusual condition occurred and there would still be Temperature to spare to allow time for quick investigation or shut down This margin may be the difference between saving or loosing the bearing On the other hand if the relay trips on its factory setting and the reason for the higher operating temperature is known it is permissible to rise the setting to some other value above operating temperature The choice for setting of an alarm and set points should be considered to the following e How critical to the operation of the plant or facility is the motor e Will safety be affected if the motor stops because of the setting without a
28. n o Note after using any cleaning method the windings should be meggared to check for damage caused by the cleaning Windings may need additional drying or other rework prior to being re insulated 8 Anti Friction Bearing Replacement Bearing Replacement Guidelines General Bearings should be replaced only with bearings of the same size rating and construction If you have questions about replacement bearings contact Continental before proceeding e When removing or replacing a ball bearing there are rules which always should be observed Following these rules closely will prevent damage to the bearing or motor and will result in longer bearing life e When removing a bearing always use an approved bearing puller e Never open the protective cover on new bearings in any location where the bearings will be exposed to dust or dirt Always open the package in a clean place and do not remove bearing from package until ready to install e Never try to clean a new ball bearing The slushing oil on new bearings should not be removed e Do not force a bearing onto a shaft by means of the outer race Do not attempt to force the bearing on a badly worn shaft or a shaft that is too large for the bearing Methods of Replacement Caution Bearing replacement should only be performed by individuals trained for these procedures e Pressing procedure Clean shafts and bearing housing thoroughly Clean dirt out of threads and g
29. nd repack with fresh grease during the major overhaul ideally within one or two year periods When regreasing horizontal motors clean the area around the inlet and grease drain and remove plugs If grease has hardened in the area around the drain plug use a wooden stick to remove the hardened grease Removal of the drain plug serves as a pressure relief when regreasing It is preferable to stop the motor and add grease slowly with a hand operated grease gun Run the motor for about ten minutes with the drain plug removed to allow excess grease to drain out When regreasing vertical motors follow same procedures for regreasing horizontal motors The following chart is a guide to the amount of grease to be added using a low pressure hand held grease gun Shaft Extension Diameter Weight of grease to be added oz Y to 1 1 4 3 1 1 4 to 1 7 8 1 1 7 8 to 2 3 8 2 2 3 8 to 3 3 3 to 4 6 4 to 5 8 Never fill the bearing housing with more than 1 3 to 1 2 full of grease as over greasing will cause excessive heat in the bearing Recommended Grease Exxon Non Fluid Oil S 58 or equivalent for normal condition Shell Cyprina NLGI 3 premium motor grease Exxon Andok C For vertical motors use stiffer grease 27 Wound Rotor Motor Supplement Slip Rings Slip rings must be kept clean and free from grease oil and dust If necessary to clean the rings use a fine grade of sandpaper to polish rings and wipe clean wi
30. ontrol so that they are energized when the motor is off and never energized when the motor is running Occasionally space heaters are mounted within the main conduit box These may be energized during motor operation o During regular maintenance the space heaters should be checked to be sure that their connections are tight and to be sure that they are free from dirt and dust accumulations Be sure that power to the motor and the space heater is turned off and locked out before making these checks There is no other maintenance to perform on a space heater e Oil Circulation System o Continental can supply provisions for connecting an oil circulation system to the motor for bearing lubrication but does not supply the oil circulation system itself These systems are used when the application requires more oil circulating than the oil rings can move Please refer to the manual supplied by the system provider for maintenance instructions 20 e Differential Air Pressure Switch o The switch is connected to probes mounted on the upstream and downstream sides of the filters in WPII applications and provides an indication of filters becoming clogged by closing a contact when the pressure drop between the two probes increases to a preset level Differential Air Pressure Indicator o The indicator is connected to probes mounted on the upstream and downstream sides of the filters in WPII applications and provides an indication of the filter
31. overheating Insulation Resistance e Insulation resistance is useful in determining the presence of moisture in the winding It is suggested that insulation resistance readings be taken every three months e Any sudden downward trend of the insulation resistance values will indicate that special maintenance steps need be taken See segment on Cleaning and Insulation Renewal 6 Measurement of Insulation Resistance e The method of taking insulation resistance should be definitely controlled and following routine is suggested e Adopt a definite time of application for taking readings preferably after one minute of voltage application Make tests immediately after a shutdown When machine is relatively free from moisture e Always use the same voltage instrument e Keep a complete record of date temperature of winding and ambient temperature relative humidity and condition of winding Insulation resistance will vary inversely with the temperature That is the insulation will decrease with increase in temperature Roughly the resistance will be double for each 15 degrees drop in temperature For example if a certain insulation has a known resistance 75 degrees C then 60C the resistance should be approximately doubled and 25 degrees C it should be in the neighborhood of 10 times as great It must be emphasized that these figures are only approximations and that the rate for individual machine will usually vary eTake read
32. rooves Remove burrs and slivers Clean and oil bearing seats Press bearings on straight and square Press only on the ring which takes the tight fit Press bearings until they are seated against the shaft or housing shoulder if the bearing stops against these shoulders before the Shaft reaches its operating temperature the thermal growth of the shaft will pre load both bearings In this case the pre load force tends to pull the bearings away from the shaft shoulder This reduces design stiffness and also result in a cocked bearing Use an arbor press if available and press the shaft into the bearing supporting the inner ring on blocks Be sure the blocks do not scrape the shaft or threads 9 e Heating Procedure Another method of installing ball bearings is to heat the bearing in an oven or oil bath so that it will slide onto the shaft DO NOT USE A TORCH TO HEAT THE BEARING Use a temperature of approximately 225 degrees F Too high a temperature will damage the bearing and too low a temperature will cause the bearing to seize the shaft All parts are interchangeable with any rating having the same size bearings Jack screws and tapped holes allow for removal of the entire cartridge and bearings simultaneously There are no contact seals to leak or wear out General Bearing Information Anti Friction Bearings If possible check motor nameplate to identify the original bearings installed and replace with
33. s becoming clogged by visually showing the actual pressure drop across the filters It is important that maintenance monitor and record the reading on a regular basis in order to know when filter replacement is required e Pressure Switch o A pressure switch can be supplied to monitor air pressure oil pressure on force lube systems or water pressure on TEWAC cooling systems The device consists of an adjustable sensor and contacts When the pressure drops below the setpoint a contact closes to provide indication to the user of low pressure e Constant Level Oilers o Continental provides constant level oilers as standard on all oil lube applications They provide additional oil to replace that lost through normal long term leakage Their use does not change the oil level in the sump o They are preset at the factory and do not require any adjustments They provide an indication of the rate of oil leakage by monitoring the level in the oiler e Current Transformers for Differential Protection or Metering o Current transformers are used to determine current flow through the motors power leads Current transformers consist of a laminated iron core with windings of a predetermined ratio to be used with a specific metering device Typically three current transformers are mounted in the main conduit box one transformer per phase Ratio supplied is based on user spec e Lightning Arrestors o Lightning arrestors are designed to limit the p
34. shipment Vibration in in sec peak Speed 60hz operation NEMA std Continental 3600 15 10 1800 15 08 1200 15 08 900 12 08 720 09 07 600 08 06 For the Continental Routine Test the motor is mounted on a test plate constructed to meet the NEMA definition of a massive foundation A massive foundation is define by NEMA as one that has a vibration in any direction or plane limited during testing to 02 in s peak above any background vibrations The natural frequencies of the foundation should not coincide within 10 of the rotational frequency of the machine within 5 of two times the rotational frequency or within 5 of the one and two times electrical frequency The motor is run at no load for test measurements and is usually not at rated temperature Generally the mounting and running conditions in the field are not the same as the above definition and the resultant vibration measurement will be different usually higher that that measured on the test floor It is important that the user of the motor have a regular program of vibration measurement Beginning with a measurement of the vibration at installation and regular follow up measurements The measurement at installation will point out if there are problems with the installation and establish a baseline for monitoring changes in vibration level Note that motors with thrust bearings may measure higher on the test floor as a thrust is required to stabilize
35. th a lint free dry cloth Never use emery cloth to clean the rings A brown oxide color indicates good brush and slip life If sparking has occurred the surface of the slip ring will appear dull and black In this case it should be cleaned with a fine sandpaper do not use emery cloth If excessive or prolonged sparking has caused the slip ring to become rough or pitted the rotor should be removed and the slip ring turns down on a lathe An investigation of overloads or improper brush seating which can cause sparking should be made to eliminate the trouble wherever possible Brushes Brushholders should be kept clean and dust free to prevent brushes from sticking in their holders The spring tension on the brush should be kept as light as possible commensurate with good ring contact to prevent excessive wear of brush As brushes become worn they should be replaced by purchasing the proper size and from the motor manufacture Sparking at the brushes is a sign of improper ring contact and can be corrected by cleaning the rings readjusting the brush or replacing with a new brush This should be done as quickly as possible in order to avoid pitting the parts or causing more serious electrical damage to the motor Frequent inspection of the brushes should be made to see that A Brushes are not sticking in the holders B Pig tail shunts are properly attached to brushes and holders C Correct tension is maintained as the brushes wear D Worn out
36. ue life Impact loads severe vibration and ring fit also effect internal clearance To obtain the optimal internal clearance for a specific application these parameters must bebalanced 10 Radial And Axial Internal Clearance e Internal clearance can be separated into two categories radial and axial The total internal clearance is the amount that one ring can be displaced relative to the other ring either radially or axially e In rolling element bearings the difference between the diameter of the ball roller and the space between the inner and outer rings is radial clearance The internal space is measured at a 90 degrees angle to the shaft The clearance changes with the expansion or contraction of the bearing rings e The axial clearance is the total amount that one ring can be displaced relative to the other in an axial direction As the radial clearance increases the axial clearance increases as well The more room between the balls and the rings radial clearance the more the elements can shift in relation to each other The Best Specification for the Job e Internal clearances are designed from C1 tightest through C5 loosest or larger The higher the number the greater the radial clearance With higher clearance there is more tolerance for externally induced heat When noise and vibration must be restricted lower clearances are necessary The specific application and operating conditions determine the optimal internal
37. ular motor Part 4 Assembling the Bearings 1 Remove all the old sealing compound from the machined joint of the bearing housing parts 2 Place bottom bearing half on shaft journal assemble oil ring in place and roll in the bottom half Note Assemble lower bearing half with the temperature detector hole on the inside of the motor Reassemble the insulated position stud adjusting nut must face outside of motor with same projection as on replaced bearing This will insure the bearings will be magnetically centered on the shaft journals while operating 3 Install the bearing temperature detector in same position as before while threading the leads through the upper bearing half DO NOT PULL ON THE LEADS 4 Join the upper half of the bearing to the bottom of the bearing half fitting the temperature detector in the hole in the bottom half Bolt the two halves together The socket head screw projecting above the bearing O D must be at 12 o clock 5 Apply a thin coat of sealing compound permatex 2 to the mating surfaces of the bearing bracket and housing 6 Lower the top bearing housing threading the temperature detector leads through the top lead hole Make sure not to pinch the wire between the bearing and the housing Secure top with four bolts Seal lead hole with permatex 2 compound 7 Reconnect the bearing temperature detector leads by soldering and taping them When all the above steps are done the shaft will operate
38. uld be in accordance with the National Electric Code as well as state and local codes and consistent with local practices prior to operation 5 Maintenance General Predictive Maintenance e Electric motors are among the most efficient machines known today and will operate with a minimum of attention To keep the equipment operating at a high level of efficiency however a proactive maintenance program must be set up Regular inspections of equipment should be scheduled and records should be kept of the findings of these inspections These scheduled inspections should record the following data e Ambient temperature e Motor vibration level at the same point each time Radially DE Radially ODE Axially e Winding temperature if temperature device exists e Bearing temperature if temperature device exists e Winding meggar readings e Rotor meggar readings if a wound rotor motor e Lubrication check Level if oil lube e Examination of these records could provide an early warning of potential problems A change in value from previously taken data may be an indicator of motor or machine problems General Maintenance Issues e Motors should be kept clean and free of dirt and oil buildup If oil or grease is observed in significant quantities near shaft or seals an immediate determination should be made to determine the cause of the leak Dirt and dust on a motor can also act as an insulator and can cause motor
39. with approximately Y end play on each side of magnetic center Note The shaft location at magnetic center is scribed on the shaft extension To readjust the end play or float the insulated bearing positioning studs can be used Take off the insulating cap while adjusting with a wrench and be sure to replace it when done Replace gaskets and bearing caps Winding Temperature Protection There are a number of devices that can be used to monitor the temperature of the windings and provide a signal to an alarming device A listing of commonly used devices is as follows Klixon type thermostat with a normally closed contact Resistance Temperature Detectors RTD Thermocouple TC Thermistor 15 The Setting Temperature Protection Devices Many times the manufacturer of motors is asked by users of motors and engineers writing specifications to recommend settings of alarms and shutdown devices that use winding detectors in the windings However the motor manufacturer is not in the best position to know the correct answer for all situations The most that can be expected of the motor manufacturer is for him to give general guides lines for the appropriate settings The alarm and tripping point setting should be based on operation conditions Generally the users or the driven equipment manufacturers are in a better position to know the details required to make the proper selections Generally a conservative practice is to set a
40. y on the complete motor Our Refurbishment procedure is outlined below Receive motor inspect and test the following Routine test if motor is able to run if motor is not able to run we will complete all non running checks noted in routine test below Plus additional check as follows Check stator core loss Mechanical checks Dimensional check of all fits machined surfaces and shaft Inspect rotor for cracked or loose bars Advise customer of results of inspections and tests if no issues are identified proceed as described below If issues identified provide pictures and supporting documentation to the customer along with additional cost information Achieve agreement on path forward prior to proceeding 29 Stator Refurbishment Steam clean and bake stator VPI stator with H rated polyester VPI second VPI application optional Meggar and hi pot after VPI Rotor Refurbishment Balance rotor to better than NEMA precision balance limits Clean and prime all castings with 240hr salt spray rated primer prior to re assembly Re assemble motor utilizing new bearings Final check is CEM Routine test Apply finish coat of paint to completely assembled and tested motor Provide all documentation on inspections and tests to customer Motor is returned to customer with 1 year from ship warranty 30
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